Monitoring the concentration of antibiotics in body fluids is essential to optimizing the therapy and minimizing the risk of bacteria resistance,which can be made with electrochemical sensors tailored with appropriate...Monitoring the concentration of antibiotics in body fluids is essential to optimizing the therapy and minimizing the risk of bacteria resistance,which can be made with electrochemical sensors tailored with appropriate materials.In this paper,we report on sensors made with screen-printed electrodes(SPE)coated with fullerene(C60),reduced graphene oxide(rGO)and Nafion(NF)(C60-rGO-NF/SPE)to determine the antibiotic metronidazole(MTZ).Under optimized conditions,the C60-rGO-NF/SPE sensor exhibited a linear response in square wave voltammetry for MTZ concentrations from 2.5×10^(-7) to 34×10^(-6) mol/L,with a detection limit of 2.1×10^(-7) mol/L.This sensor was also capable of detecting MTZ in serum and urine,with recovery between 94%and 100%,which are similar to those of the standard chromatographic method(HPLC-UV).Because the C60-rGO-NF/SPE sensor is amenable to mass production and allows for MTZ determination with simple principles of detection,it fulfills the requirements of therapeutic drug monitoring programs.展开更多
A novel electrochemical method for the rapid detection of organophosphorus pesticide residues was realized on a dual-channel screen-printed electrode （DSPE） that was integrated with a portable smartphone-controlled ...A novel electrochemical method for the rapid detection of organophosphorus pesticide residues was realized on a dual-channel screen-printed electrode （DSPE） that was integrated with a portable smartphone-controlled potentiostat. The two carbon working channels of DSPE were first modified by electrodepositing of Prussian blue. The channels were then modified with acetylcholinesterase （ACHE） via Nation. The inhibition ratio of AChE was detected by comparing the electrical current of acetylthiocholine （ATCh） that was catalyzed by the enzyme electrodes with （channel 1） and without （channel 2） organophosphorus pesticide. Inhibition ratios were related with the negative logarithm of the organophosphorus pesticide （trichlorfon, oxamyl, and isocarbophos） concentrations at optimum experimental conditions （pH 6.9 of electrolyte, 0.2V working potential, 2.5μL AChE modification amount, and 15 min inhibition time）. The linear equations were 1%=32.301gC＋ 253.3 （R=0.9750） for isocarbophos, I% = 35.991gC＋ 270.1 （R = 0.9668） for chlorpyrifos, and 1% = 33.701gC＋ 250.5 （R = 0.9606） for trichlorfon. The detection limits were calculated as 10-7 g/mL. Given that the inhibition ratios were only related with pesticide concentration and not with pesticide species, the proposed electrodes and electrometer can rapidly detect universal organophosphorus pesticides and assess pesticide pollution.展开更多
In this study, gold nanoparticles and thermochromic composite films modified screen-printed carbon electrodes (TM-AuNPsSPCEs) were developed as a platform for the simultaneous detection of protein and temperature. The...In this study, gold nanoparticles and thermochromic composite films modified screen-printed carbon electrodes (TM-AuNPsSPCEs) were developed as a platform for the simultaneous detection of protein and temperature. The TM-AuNPs composited film had better sensitivity resulting from the gold nanoparticles amplification effect. A phase transition model analysis of TM-AuNPs films found that the TM-AuNPs films had three-phase transition intervals (<45℃, 45℃ to 80℃ and >80℃) which accommodated the temperature requirements for protein denaturation. When used to detect different concentrations of haemoglobin (Hb) solution, the TM-AuNPs modified SPCEs had a better sensitivity in detecting the different concentrations in comparison to TM and AuNP modified SPCEs which showed no clear sensitivity towards the different Hb concentrations. The dual detection and excellent sensitivity show a good application prospect for the study of the TM-AuNPs composite film.展开更多
CuO nanoparticles were successfully synthesized via a two-jet electrospun method,and then screen-printed on silver-carbon electrodes,forming CuO-modified Ag-C(CuO/Ag-C)disposable strip electrodes.In natural environmen...CuO nanoparticles were successfully synthesized via a two-jet electrospun method,and then screen-printed on silver-carbon electrodes,forming CuO-modified Ag-C(CuO/Ag-C)disposable strip electrodes.In natural environment condition for glucose detection,the obtained CuO/Ag-C electrodes show a high sensitivity of 540 nA·mM^(-1)·cm^(-2),and a low limit of detection(0.68 mM)in a wide linear response range of 0.68 mM and 3 mM(signal/noise=3),respectively.In addition,the CuO/Ag-C electrodes also exhibit excellent anti-interference,air stability and repeatability.As a result,the fabrication of CuO nanoparticles via an electrospun process and the technique of screen-printed electrodes are of great significance for glucose detection.展开更多
Vanadium redox flow batteries(VRFBs)are a means of large-scale energy storage due to their excellent scalability,safety,long cycling life,and decoupled power and energy capacities.However,the slow redox kinetics of va...Vanadium redox flow batteries(VRFBs)are a means of large-scale energy storage due to their excellent scalability,safety,long cycling life,and decoupled power and energy capacities.However,the slow redox kinetics of vanadium species on conventional carbon electrodes remains a major limitation to their performance.We investigated the deposition of carbon black,carbon nanotubes,and electrochemically exfoliated graphene(Exf-Gr)onto thermally-activated carbon paper(ACP)by spray coating to increase the electrode electrocatalytic activity.The modified electrodes were characterized using scanning electron microscopy,X-ray diffraction,Raman spectroscopy,X-ray photoelectron microscopy,and surface area analysis,while their electrochemical properties were evaluated by cyclic voltammetry,electrochemical impedance spectroscopy,and singlecell VRFB testing.Among the modified electrodes,Exf-Gr/ACP had the best performance,achieving a 2.9-fold reduction in charge transfer resistance compared to pristine ACP and delivering 2.5 times the discharge capacity in single-cell tests.This improvement is attributed to Exf-Gr’s high surface area,favorable catalytic activity,and excellent dispersion on the ACP substrate.Surface modification with electrochemically exfoliated graphene is a highly effective strategy for improving the electrode performance in VRFB systems,with significant implications for large-scale energy storage.展开更多
Metals,indispensable since the Bronze Age,remain pivotal in modern technologies due to their exceptional properties and versatility.Beyond traditional machining,advanced nano/micro-machining techniques enable the fabr...Metals,indispensable since the Bronze Age,remain pivotal in modern technologies due to their exceptional properties and versatility.Beyond traditional machining,advanced nano/micro-machining techniques enable the fabrication of metallic nano/micro structures with high precision in shape,size,and pattern.These structures endow flexible electrodes with outstanding electrical,mechanical,optical,and electrochemical performance,enabling growing applications in flexible optoelectronics,epidermal electronics,energy harvesting,and biochemical sensing.This review provides a comprehensive overview of the fabrication strategies for flexible electrodes made from metal meshes,metal nanowires,and liquid metals.The current advancements,existing challenges,and emerging technologies are systematically discussed.Furthermore,the progression toward ultra-thin,soft epidermal electrodes is explored,with an emphasis on novel in situ and transfer fabrication methods.We examine the underlying mechanisms,performance indicators,and their integration for on-skin applications,including bioelectric sensing,electrical stimulation,and energy harvesting.Finally,we highlight the remaining challenges in performance improvement and industrialization of flexible and epidermal electrodes,along with future opportunities for integrating multimodal systems and leveraging artificial intelligence to enhance their functionalities.展开更多
Driven by the trend of device miniaturization and high-density integration,the interaction between adjacent electrodes has become a critical factor affecting the interfacial reliability of thermoelectric(TE)structures...Driven by the trend of device miniaturization and high-density integration,the interaction between adjacent electrodes has become a critical factor affecting the interfacial reliability of thermoelectric(TE)structures.This study investigates the influence of adjoining electrode interactions on the interfacial response of a multi-electrode/TE substrate structure,including interfacial stresses and stress intensity factors at the electrode ends.To solve the corresponding boundary-value problem,the Fourier transforms are adopted to derive a governing integro-differential equation for the interfacial shear stress in multi-electrode systems,incorporating the TE effects as generalized forces on the right-hand side.The results show that both the interfacial tension and transverse stress in the electrodes are significantly affected by the presence of adjacent electrodes.The interaction between neighboring electrodes diminishes as their spacing increases or when an adhesive interlayer is introduced.Furthermore,the softer and thinner electrodes,the softer and thicker adhesive interlayer,and the smaller TE loads are found to be beneficial for improving the interfacial performance.These findings may contribute to the accurate measurement in surface sensors and layout design of multi-point health monitoring systems for TE structures.展开更多
Even in small concentrations,toxic metals like lead,cadmium,and mercury are dangerous to the environment and human health.Environmental monitoring depends on precisely identifying these heavy metals,particularly cadmi...Even in small concentrations,toxic metals like lead,cadmium,and mercury are dangerous to the environment and human health.Environmental monitoring depends on precisely identifying these heavy metals,particularly cadmium ions(Cd(Ⅱ)).In this study,we present a novel screen-printed carbon electrode(SPCE)modified with single crystallineα-Fe_(2)O_(3)nano-hexagons that functions as a sensor for detecting Cd(Ⅱ).The performance of the fabricated sensor was thoroughly assessed and compared with unmodified SPCE using the voltammetric method.The crystalline structure of the synthesizedα-Fe_(2)O_(3)nano-hexagons was confirmed through XRD,and surface analysis revealed an average diameter and thickness of 86 nm and 9 nm,respectively.Theα-Fe_(2)O_(3)modified SPCE yields a 7-fold enhanced response(at pH 5.0 vs.Ag/AgCl)to Cd(Ⅱ)than bare SPCE.The modified electrode effectively detects Cd(Ⅱ)with a linear response range of up to 333.0μmol/L and a detection limit of 0.65 nmol/L under ideal circumstances.This newly fabricated sensor offers significant potential for environmental monitoring applications by providing outstanding practicality,anti-interference ability,and repeatability for detecting Cd(Ⅱ)in water samples.展开更多
α-MnO_(2) is a promising,inexpensive,and readily producible catalyst for the oxygen reduction reaction(ORR)in alkaline media,but its application is limited by low electronic conductivity.In this study,we enhance the ...α-MnO_(2) is a promising,inexpensive,and readily producible catalyst for the oxygen reduction reaction(ORR)in alkaline media,but its application is limited by low electronic conductivity.In this study,we enhance the performance ofα-MnO_(2) electrodes by systematically varying theα-MnO_(2)-to-Vulcan ratio within the catalyst layer.Electrodes are evaluated in a gas diffusion electrode(GDE)half-cell,where an optimized catalyst layer composition leads to significantly improved ORR performance.By finetuning both theα-MnO_(2)-to-Vulcan ratio and theα-MnO_(2) loading,the electrode outperforms a commercial MnO_(2)-based electrode and approaches the performance of the Pt/C benchmark.The improvement is attributed to the presence of a three-dimensional(3D)Vulcan network electronically connecting catalytically activeα-MnO_(2) sites with the substrate.Additionally,the optimized electrodes are employed in a prototype Al-O_(2) flow cell.Under constant oxygen flow,power densities exceed 250 mW cm^(-2),which is significantly higher than that of conventional Al-air batteries.Electrochemical impedance spectroscopy combined with distribution of relaxation times(DRT)analysis enables the separation of anode and cathode charge transfer impedances without the need for an additional reference electrode.The analysis reveals that the anode contributes more than twice as much impedance as the cathode,highlighting the need for further anode optimization.This work demonstrates a transferable approach for catalyst layer screening under technically relevant conditions in the GDE half-cell.Subsequent measurements in an Al-O_(2) flow cell validate the approach.The methodology is widely applicable to the development of advanced electrodes for a variety of metal-air battery technologies.展开更多
A sensitive and specific immunosensor for the detection of the hormones cortisol and lactate in human or animal biological fluids, such as sweat and saliva, was devised using the label-free electrochemical chronoamper...A sensitive and specific immunosensor for the detection of the hormones cortisol and lactate in human or animal biological fluids, such as sweat and saliva, was devised using the label-free electrochemical chronoamperometric technique. By using these fluids instead of blood,the biosensor becomes noninvasive and is less stressful to the end user, who may be a small child or a farm animal.Electroreduced graphene oxide(e-RGO) was used as a synergistic platform for signal amplification and template for bioconjugation for the sensing mechanism on a screenprinted electrode. The cortisol and lactate antibodies were bioconjugated to the e-RGO using covalent carbodiimide chemistry. Label-free electrochemical chronoamperometric detection was used to analyze the response to the desired biomolecules over the wide detection range. A detection limit of 0.1 ng mL^(-1) for cortisol and 0.1 mM for lactate was established and a correlation between concentration and current was observed. A portable, handheld potentiostat assembled with Bluetooth communication and battery operation enables the developed system for point-of-care applications. A sandwich-like structure containing the sensing mechanisms as a prototype was designed to secure the biosensor to skin and use capillary action to draw sweat or other fluids toward the sensing mechanism. Overall, the immunosensor shows remarkable specificity, sensitivity as well as the noninvasive and point-of-care capabilities and allows the biosensor to be used as a versatile sensing platform in both developed and developing countries.展开更多
are time-consuming and not sensitive enough.However,bacteria typically connect to electrodes through biofilm formation,leading to problems due to lack of uniformity or long device production times.A suitable immobilis...are time-consuming and not sensitive enough.However,bacteria typically connect to electrodes through biofilm formation,leading to problems due to lack of uniformity or long device production times.A suitable immobilisation technique can overcome these challenges.Still,they may respond more slowly than biofilm-based electrodes because bacteria gradually adapt to electron transfer during biofilm formation.In this study,we propose a controlled and reproducible way to fabricate bacteria-modified electrodes.The method consists of an immobilisation step using a cellulose matrix,followed by an electrode polarization in the presence of ferricyanide and glucose.Our process is short,reproducible and led us to obtain ready-to-use electrodes featuring a high-current response.An excellent shelf-life of the immobilised electrochemically active bacteria was demonstrated for up to one year.After an initial 50% activity loss in the first month,no further declines have been observed over the following 11 months.We implemented our bacteria-modified electrodes to fabricate a lateral flow platform for toxicity monitoring using formaldehyde(3%).Its addition led to a 59% current decrease approximately 20 min after the toxic input.The methods presented here offer the ability to develop a high sensitivity,easy to produce,and long shelf life bacteria-based toxicity detectors.展开更多
The electrochemical oxidation behavior and voltammetric assay of gemifloxacin were investigated using differential-pulse and cyclic voltammetry on a screen-printed carbon electrode.The effects of pH,scan rates,and con...The electrochemical oxidation behavior and voltammetric assay of gemifloxacin were investigated using differential-pulse and cyclic voltammetry on a screen-printed carbon electrode.The effects of pH,scan rates,and concentration of the drug on the anodic peak current were studied.Voltammograms of gemifloxacin in Tris-HCl buffer（pH 7.0） exhibited a well-defined single oxidation peak.A differential-pulse voltammetric procedure for the quantitation of gemifloxacin has been developed and suitably validated with respect to linearity,limits of detection and quantification,accuracy,precision,specificity,and robustness.The calibration was linear from 0.5 to 10.0 μM,and the limits of detection and quantification were 0.15 and 5.0 μM.Recoveries ranging from 96.26% to 103.64% were obtained.The method was successfully applied to the determination of gemifloxacin in pharmaceutical tablets without any pre-treatment.Excipients present in the tablets did not interfere in the assay.展开更多
In a pulsed plasma thruster,the voltage distribution between the electrodes is a key factor that influences the ionization process.However,few researchers have conducted in-depth studies of this phenomenon in the past...In a pulsed plasma thruster,the voltage distribution between the electrodes is a key factor that influences the ionization process.However,few researchers have conducted in-depth studies of this phenomenon in the past.Reported here are measurements of the voltage distribution between the plates of a parallel-plate pulsed plasma thruster under different discharge voltages,based on which the variations in the total circuit inductance and resistance as well as those between the plates are calculated.The results show that the time-averaged voltage across the plates accounts for 28.7%-50.4%of the capacitor voltage.As the capacitor initial voltage increases from 1250 V to 2000 V,the voltage across the plates rises,but its proportion relative to the capacitor voltage decreases.For every 250 V increase in the capacitor initial voltage,the average voltage proportion across the plates decreases by approximately 2%-3%.Additionally,the voltage proportion decreases gradually from the end near the propellant outward.The voltage distribution ratio between the plates is correlated with the proportions of the resistance and inductance between the plates relative to the total circuit.展开更多
Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)is a highly successful conductive polymer utilized as an electrode material in energy storage units for portable and wearable electronic de-vices.Neve...Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)is a highly successful conductive polymer utilized as an electrode material in energy storage units for portable and wearable electronic de-vices.Nevertheless,employing PEDOT:PSS in supercapacitors(SC)in its pristine state presents challenges due to its suboptimal electrochemical performance and operational instability.To surmount these limita-tions,PEDOT:PSS has been integrated with carbon-based materials to form flexible electrodes,which ex-hibit physical and chemical stability during SC operation.We developed a streamlined fabrication process for high-performance SC electrodes composed of PEDOT:PSS and carbon quantum dots(CQDs).The CQDs were synthesized under microwave irradiation,yielding green-and red-light emissions.Through optimiz-ing the ratios of CQDs to PEDOT:PSS,the SC electrodes were prepared using a spray-coating technique,marking a significant improvement in device performance with a high volumetric capacitance(104.10 F cm-3),impressive energy density(19.68 Wh cm^(-3)),and excellent cyclic stability,retaining~85% of its original volumetric capacitance after 15,000 repeated GCD cycles.Moreover,the SCs,when utilized as a flexible substrate,demonstrated the ability to maintain up to~85% of their electrochemical performance even after 3,000 bending cycles(at a bending angle of 60°).These attributes render this hybrid composite an ideal candidate for a lightweight smart energy storage component in portable and wearable electronic technologies.展开更多
This study explores the potential of Michelia champaca wood as a sustainable and locally available precursor for the fabrication of high-performance supercapacitor electrodes.Activated carbons were synthesized through...This study explores the potential of Michelia champaca wood as a sustainable and locally available precursor for the fabrication of high-performance supercapacitor electrodes.Activated carbons were synthesized through single-step carbonization at 400℃ and 500℃(SSC-400℃ and SSC-500℃) and double-step carbonization at 400℃(DSC-400℃),with all samples activated using H_(3)PO_(4).The effects of carbonization stratergy on the structural,morphological,and electrochemical characteristics of the resulting carbon materials were systematically evaluated,using techniques such as BET,SEM,TEM,XRD,Raman scattering,FTIR,CV,GCD and EIS.Among the samples,SSC-400℃ exhibited the best electrochemical performance,achieving a specific capacitance of 292.2 Fg^(-1),an energy density of 6.4 Wh kg^(-1),and a power density of 198.4 W kg^(-1).This superior performance is attributed to its optimized pore structure,improved sur-face functionality and enhanced conductivity.SSC-500℃showed marginally lower performance,whereas,DSC-400℃ displayed the least favorable results,indicating that double-step carbonization process may negatively affect material quality by disrupting the pore network.This work highlights a strong correlation between synthesis methodology and electrochemical efficiency,directly reinforcing the importance of process optimization in electrode material develop-ment.The findings contribute to the broader goal of developing cost-effective,renewable and environmentally friendly energy storage systems.By valorizing biomass waste,the study supports global movements toward green energy technologies and circular carbon economies,offering a viable pathway for sustainable supercapacitor development and practical applications in energy storage devices.展开更多
Multicomponent Gd_(1−x)Sm_(x)Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)double perovskites are optimized for application in terms of chemical composi-tion and morphology for the use as oxygen electrodes in solid oxide cells.Structur...Multicomponent Gd_(1−x)Sm_(x)Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)double perovskites are optimized for application in terms of chemical composi-tion and morphology for the use as oxygen electrodes in solid oxide cells.Structural studies of other physicochemical properties are con-ducted on a series of materials obtained by the sol-gel method with different ratios of Gd and Sm cations.It is documented that changing the x value,and the resulting adjustment of the average ionic radius,have a significant impact on the crystal structure,stability,as well as on the total conductivity and thermomechanical properties of the materials,with the best results obtained for the Gd_(0.75)Sm_(0.2)5Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)composition.Oxygen electrodes are prepared using the selected compound,allowing to obtain low polarization resistance values,such as 0.086Ω·cm^(2)at 800℃.Systematic studies of electrocatalytic activity are conducted using La_(0.8)Sr_(0.2)Ga_(0.8)Mg_(_(0.2))O_(3−δ)as the electrolyte for all electrodes,and Ce_(0.8)Gd_(0.2)O_(2−δ)electrolyte for the best performing Gd_(0.75)Sm_(0.2)5Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)electrodes.The electrochemical data are analyzed using the distribution of relaxation times method.Also,the influence of the preparation method of the electrode material is in-ve`stigated using the electrospinning technique.Finally,the performance of the Gd_(0.75)Sm_(0.2)5Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)electrodes is tested in a Ni-YSZ(yttria-stabilized zirconia)anode-supported cell with a Ce_(0.8)Gd_(0.2)O_(2−δ)buffer layer,in the fuel cell and electrolyzer operating modes.With the electrospun electrode,a power density of 462 mW·cm^(−2)is obtained at 700℃,with a current density of ca.0.2 A·cm^(−2)at 1.3 V for the electrolysis at the same temperature,indicating better performance compared to the sol-gel-based electrode.展开更多
Fully implanted brain-computer interfaces(BCIs)are preferred as they eliminate signal degradation caused by interference and absorption in external tissues,a common issue in non-fully implanted systems.To optimize the...Fully implanted brain-computer interfaces(BCIs)are preferred as they eliminate signal degradation caused by interference and absorption in external tissues,a common issue in non-fully implanted systems.To optimize the design of electroencephalography electrodes in fully implanted BCI systems,this study investigates the penetration and absorption characteristics of microwave signals in human brain tissue at different frequencies.Electromagnetic simulations are used to analyze the power density distribution and specific absorption rate(SAR)of signals at various frequen-cies.The results indicate that lower-frequency signals offer advantages in terms of power density and attenuation coeffi-cients.However,SAR-normalized analysis,which considers both power density and electromagnetic radiation hazards,shows that higher-frequency signals perform better at superficial to intermediate depths.Specifically,at a depth of 2 mm beneath the cortex,the power density of a 6.5 GHz signal is 247.83%higher than that of a 0.4 GHz signal.At a depth of 5 mm,the power density of a 3.5 GHz signal exceeds that of a 0.4 GHz signal by 224.16%.The findings suggest that 6.5 GHz is optimal for electrodes at a depth of 2 mm,3.5 GHz for 5 mm,2.45 GHz for depths of 15-20 mm,and 1.8 GHz for 25 mm.展开更多
Introduction The generation of biological wastes such as cow dung and aloe vera waste(AVW)causes a serious ecological pollution.The microbial electrolytic cell coupled with anaerobic digestion(MEC-AD)system can make a...Introduction The generation of biological wastes such as cow dung and aloe vera waste(AVW)causes a serious ecological pollution.The microbial electrolytic cell coupled with anaerobic digestion(MEC-AD)system can make a rational utilization of these biodegradable organic wastes,which is of vital importance for alleviating environmental deterioration and reducing resource waste.Electrode materials and accelerants are the two major factors that affect methane production in the MEC-AD system.They affect microbial attachment and electron transfer in the MEC-AD system.Bio-based carbon materials are carbon materials prepared from biomass as raw materials.They have characteristics such as a rich pore structure,good chemical stability,biocompatibility,and controllable surface properties,which can be used as accelerants and electrodes in the MEC-AD system to optimize its performance.This study was to investigate the influence of biomass-derived carbon as an electrode and accelerant on the performance of the MEC-AD system,and the mechanism for increasing the production of biogas and methane was also analyzed,thus providing a basis for the multifunctional application of biomass-derived carbon in the MEC-AD system.Methods A series of experimental methods were adopted to study the MEC-AD system.Two types of bio-based carbon,i.e.,aloe vera waste derived spherical carbon(AVW-SC)and porous carbon(AVW-PC),were synthesized via hydrothermal carbonization.The raw AVW material was washed with water,dried,ground,and subjected to hydrothermal treatment to obtain AVW-SC.After activating AVW-SC with KOH,it was carbonized in a tube furnace to obtain AVW-PC.In the preparation of the electrodes,bio-based carbon(AVW-SC and AVW-PC)was mixed with 5%polytetrafluoroethylene powder in ethanol and deionized water,and then ground in a ball mill for 4 h to form a slurry.The slurry was evenly sprayed on the Ti mesh,dried and sintered in N2 atmosphere at 360℃to obtain Ti-SC and Ti-PC electrodes.Four groups of experiments were conducted to determine the optimal voltage,compare different carbon electrodes,and explore the optimal coating amount.The MEC-AD reactor adopted 500 mL wide-mouthed glass bottles with a working volume of 400 mL.Each MEC-AD system received a co-substrate mixture of cattle dung and aloe vera waste and inoculum of sewage sludge in a mass ratio of 3:7.Afterward,they were placed at(36±1)℃for 35 d.The biogas was collected by a water displacement method.The materials were analyzed by characterization techniques such as X-ray diffraction(XRD)and scanning electron microscopy(SEM),and electrochemical tests were conducted on different electrodes.The composition,pH,TS,VS,TCOD and nutrient content of biogas were analyzed by standard chemical methods.Microbial community analysis was conducted using high-throughput sequencing technology.The modified Gompertz model was adopted to predict the kinetic parameters,and the coulombic efficiency and methane recovery rate were calculated according to a specific formula.Results and discussion The result shows that AVW-SC is spherical and closely aggregated,while AVW-PC has a three-dimensional network structure,with average pore diameter of 9.77 nm.The electron exchange capacity(EEC)of AVW-PC(i.e.,0.75μmol·e-/g)is higher than that of AVW-SC(i.e.,0.15μmol·e-/g),indicating a better electron exchange capacity.These results indicate that AVW-PC provides more substrate and bacteria accumulation sites,and has better electron-donating and electron-accepting ability,thus improving the digestion efficiency.In the MEC-AD system,using Ti mesh as an electrode,the effect of different voltages(i.e.,0,0.4,0.6,0.8 V and 1.2 V)on the system performance is investigated,obtaining the optimum biogas production and organic matter degradation rate at 0.8 V.AVW-SC and AVW-PC are respectively coated on Ti mesh as electrodes.The results show that the MEC-AD system with AVW-PC coated Ti mesh as the electrode has a better performance.The electrochemical analysis shows that the electrode coated with AVW-PC has a larger specific capacitance and a smaller charge transfer resistance,indicating that AVW-PC can improve the electrochemical properties and electron transfer ability of MEC-AD system.The influence of coating amount(i.e.,0.025,0.05,0.10,0.15,and 0.20 g)of AVW-PC on the MEC-AD system is investigated.At a coating amount of AVW-PC of 0.1 g,the cumulative biogas production and methane content of the Ti_(0.8)-PC_90.1) group both reach the maximum values.Different doses of AVW-PC(i.e.,0.10%,0.15%,0.20%,and 0.25%)are added as accelerants in Ti_(0.8)-PC_90.1).At the addition amount of AVW-PC of 0.20%,the Ti_(0.8)-PC_90.1)/PC0.2 group performs the optimum biogas production(i.e.,633.63 mL/g VS),methane content(i.e.,65.85%),and total nutrient content of biogas residue(i.e.,42.30 g/kg).In Ti_(0.8)-PC_90.1)/PC0.2,Bacteroidales,Pseudomonadales,Oscillospirales,Methanobacteraceae,Methanospirillaceae,Methanosarcinacea and Methanosaetaceae significantly increase.The increase in microbial diversity promotes interspecific hydrogen transfer(IHT),interspecific acetic transfer(IAT),and direct interspecific electron transfer(DIET),thereby enhancing methanogenic efficiency.Conclusions AVW-SC and AVW-PC were utilized as electrodes and accelerants to enhance methane yield in MEC-AD system.The Ti mesh electrode coated with different concentrations of AVW-PC achieved the optimal biogas production at 0.8 V.Specifically,the Ti_(0.8)-PC_90.1) combination could generate the maximum total amount of biogas and methane proportion.The Ti_(0.8)-PC_90.1)/PC0.2 combination exhibited the optimum performance(i.e.,biogas yield of 633.63 mL/g VS,methane content of 65.85%and total nutritional content of 42.30 g/kg).High abundances of Bacteroidales,Pseudomonadales,Oscillospirales,Methanobacteraceae,Methanospirillaceae,Methanosarcinaceae,and Methanosaetaceae appeared in the Ti_(0.8)-PC_90.1)/PC0.2 group,compared to other groups.In addition,an increased microbial diversity led to an enhanced methane production through processes like DIET.This research could highlight the potential significance of AVW-PC as both electrode and accelerator for increasing methane production and provide a perspective for improving MEC-AD performance through multiple applications of biomass-derived carbon.展开更多
Surgical electrodes are frequently associated with disadvantages such as high surface adhesion and severe thermal damage to adjacent normal tissues,which threaten operation quality and patient safety.In this study,by ...Surgical electrodes are frequently associated with disadvantages such as high surface adhesion and severe thermal damage to adjacent normal tissues,which threaten operation quality and patient safety.In this study,by mimicking the micromorphology and bio-anti-adhesion of shark skin,we proposed a strategy that utilized nanoscale aluminium oxide(Al_(2)O_(3))films deposited on bioinspired shark skin(BSS)microstructures to design a composite surface(Al_(2)O_(3)@BSS)and integrated it into both flat sides of the surgical electrodes.Micro/nano-manufacturing of the Al_(2)O_(3)@BSS surface was sequentially accomplished using nanosecond laser texturing,atomic layer deposition,and low-temperature annealing,endowing it with excellent blood-repellent properties.Visualisation experiments revealed that the tensile stress gradient of the blood coagulum with increasing thickness under a thermal field prompted it to separate from the Al_(2)O_(3)@BSS surface,resulting in anti-adhesion.Furthermore,it was observed for the first time that Al_(2)O_(3) films could transiently excite discharge along a dielectric surface(DADS)to ablate tissues while suppressing Joule heat,thereby minimising thermal damage.A combination of ex vivo tissue and living mouse experiments demonstrated that the Al_(2)O_(3)@BSS electrodes exhibited optimal comprehensive performance in terms of anti-adhesion,damage minimisation,and drag reduction.In addition,the Al_(2)O_(3)@BSS electrodes possessed remarkable antibacterial efficacy against E.coli and S.aureus.The proposed strategy can meet the extreme application requirements of surgical electrodes to improve operation quality and offer valuable insights for future studies.展开更多
In order to address the current inability of screen printing to monitor printing pressure online,an online printing pressure monitoring system applied to screen printing machines was designed in this study.In this stu...In order to address the current inability of screen printing to monitor printing pressure online,an online printing pressure monitoring system applied to screen printing machines was designed in this study.In this study,the consistency of printed electrodes was measured by using a confocal microscope and the pressure distribution detected by online pressure monitoring system was compared to investigate the relationship.The results demonstrated the relationship between printing pressure and the consistency of printed electrodes.As printing pressure increases,the ink layer at the corresponding position becomes thicker and that higher printing pressure enhances the consistency of the printed electrodes.The experiment confirms the feasibility of the online pressure monitoring system,which aids in predicting and controlling the consistency of printed electrodes,thereby improving their performance.展开更多
基金The authors gratefully acknowledge the financial support granted by CNPq,INEO,CAPES and FAPESP(Grant Nos.:2018/22214-6,2017/24053-7 and 2016/0991-5).
文摘Monitoring the concentration of antibiotics in body fluids is essential to optimizing the therapy and minimizing the risk of bacteria resistance,which can be made with electrochemical sensors tailored with appropriate materials.In this paper,we report on sensors made with screen-printed electrodes(SPE)coated with fullerene(C60),reduced graphene oxide(rGO)and Nafion(NF)(C60-rGO-NF/SPE)to determine the antibiotic metronidazole(MTZ).Under optimized conditions,the C60-rGO-NF/SPE sensor exhibited a linear response in square wave voltammetry for MTZ concentrations from 2.5×10^(-7) to 34×10^(-6) mol/L,with a detection limit of 2.1×10^(-7) mol/L.This sensor was also capable of detecting MTZ in serum and urine,with recovery between 94%and 100%,which are similar to those of the standard chromatographic method(HPLC-UV).Because the C60-rGO-NF/SPE sensor is amenable to mass production and allows for MTZ determination with simple principles of detection,it fulfills the requirements of therapeutic drug monitoring programs.
基金financially supported by the Natural Science Foundation of Zhejiang Province(No.LQ17B050002)Analysis and Measurement Foundation of Zhejiang Province(No.2015C37068)
文摘A novel electrochemical method for the rapid detection of organophosphorus pesticide residues was realized on a dual-channel screen-printed electrode （DSPE） that was integrated with a portable smartphone-controlled potentiostat. The two carbon working channels of DSPE were first modified by electrodepositing of Prussian blue. The channels were then modified with acetylcholinesterase （ACHE） via Nation. The inhibition ratio of AChE was detected by comparing the electrical current of acetylthiocholine （ATCh） that was catalyzed by the enzyme electrodes with （channel 1） and without （channel 2） organophosphorus pesticide. Inhibition ratios were related with the negative logarithm of the organophosphorus pesticide （trichlorfon, oxamyl, and isocarbophos） concentrations at optimum experimental conditions （pH 6.9 of electrolyte, 0.2V working potential, 2.5μL AChE modification amount, and 15 min inhibition time）. The linear equations were 1%=32.301gC＋ 253.3 （R=0.9750） for isocarbophos, I% = 35.991gC＋ 270.1 （R = 0.9668） for chlorpyrifos, and 1% = 33.701gC＋ 250.5 （R = 0.9606） for trichlorfon. The detection limits were calculated as 10-7 g/mL. Given that the inhibition ratios were only related with pesticide concentration and not with pesticide species, the proposed electrodes and electrometer can rapidly detect universal organophosphorus pesticides and assess pesticide pollution.
文摘In this study, gold nanoparticles and thermochromic composite films modified screen-printed carbon electrodes (TM-AuNPsSPCEs) were developed as a platform for the simultaneous detection of protein and temperature. The TM-AuNPs composited film had better sensitivity resulting from the gold nanoparticles amplification effect. A phase transition model analysis of TM-AuNPs films found that the TM-AuNPs films had three-phase transition intervals (<45℃, 45℃ to 80℃ and >80℃) which accommodated the temperature requirements for protein denaturation. When used to detect different concentrations of haemoglobin (Hb) solution, the TM-AuNPs modified SPCEs had a better sensitivity in detecting the different concentrations in comparison to TM and AuNP modified SPCEs which showed no clear sensitivity towards the different Hb concentrations. The dual detection and excellent sensitivity show a good application prospect for the study of the TM-AuNPs composite film.
基金Funded by Cofoe Medical Technology Co.,Ltd and the Scientific Research Start-up Funds of Hexi University(No.KYQD2022006)。
文摘CuO nanoparticles were successfully synthesized via a two-jet electrospun method,and then screen-printed on silver-carbon electrodes,forming CuO-modified Ag-C(CuO/Ag-C)disposable strip electrodes.In natural environment condition for glucose detection,the obtained CuO/Ag-C electrodes show a high sensitivity of 540 nA·mM^(-1)·cm^(-2),and a low limit of detection(0.68 mM)in a wide linear response range of 0.68 mM and 3 mM(signal/noise=3),respectively.In addition,the CuO/Ag-C electrodes also exhibit excellent anti-interference,air stability and repeatability.As a result,the fabrication of CuO nanoparticles via an electrospun process and the technique of screen-printed electrodes are of great significance for glucose detection.
基金supported by the University of Seoul’s 2025 Research Fund.
文摘Vanadium redox flow batteries(VRFBs)are a means of large-scale energy storage due to their excellent scalability,safety,long cycling life,and decoupled power and energy capacities.However,the slow redox kinetics of vanadium species on conventional carbon electrodes remains a major limitation to their performance.We investigated the deposition of carbon black,carbon nanotubes,and electrochemically exfoliated graphene(Exf-Gr)onto thermally-activated carbon paper(ACP)by spray coating to increase the electrode electrocatalytic activity.The modified electrodes were characterized using scanning electron microscopy,X-ray diffraction,Raman spectroscopy,X-ray photoelectron microscopy,and surface area analysis,while their electrochemical properties were evaluated by cyclic voltammetry,electrochemical impedance spectroscopy,and singlecell VRFB testing.Among the modified electrodes,Exf-Gr/ACP had the best performance,achieving a 2.9-fold reduction in charge transfer resistance compared to pristine ACP and delivering 2.5 times the discharge capacity in single-cell tests.This improvement is attributed to Exf-Gr’s high surface area,favorable catalytic activity,and excellent dispersion on the ACP substrate.Surface modification with electrochemically exfoliated graphene is a highly effective strategy for improving the electrode performance in VRFB systems,with significant implications for large-scale energy storage.
基金supported by the Basic and Applied Basic Research Foundation of Guangdong province(2024A1515030155 and 2022A1515010272)Natural Science Foundation of China(61904067)+2 种基金Basic and Applied Basic Research Foundation of Guangzhou city(202102020758)Open funding from State Key Laboratory of Optoelectronic Materials and Technologies(Sun Yat-Sen University,OEMT2022-KF-08)Fundamental Research Funds for the Central Universities(11625109,11621405)。
文摘Metals,indispensable since the Bronze Age,remain pivotal in modern technologies due to their exceptional properties and versatility.Beyond traditional machining,advanced nano/micro-machining techniques enable the fabrication of metallic nano/micro structures with high precision in shape,size,and pattern.These structures endow flexible electrodes with outstanding electrical,mechanical,optical,and electrochemical performance,enabling growing applications in flexible optoelectronics,epidermal electronics,energy harvesting,and biochemical sensing.This review provides a comprehensive overview of the fabrication strategies for flexible electrodes made from metal meshes,metal nanowires,and liquid metals.The current advancements,existing challenges,and emerging technologies are systematically discussed.Furthermore,the progression toward ultra-thin,soft epidermal electrodes is explored,with an emphasis on novel in situ and transfer fabrication methods.We examine the underlying mechanisms,performance indicators,and their integration for on-skin applications,including bioelectric sensing,electrical stimulation,and energy harvesting.Finally,we highlight the remaining challenges in performance improvement and industrialization of flexible and epidermal electrodes,along with future opportunities for integrating multimodal systems and leveraging artificial intelligence to enhance their functionalities.
基金Project supported by the National Natural Science Foundation of China(Nos.12502117,12272269,11972257)the Natural Science Foundation of Ningxia of China(No.2024AAC03018)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Shanghai Gaofeng Project for University Academic Program Development。
文摘Driven by the trend of device miniaturization and high-density integration,the interaction between adjacent electrodes has become a critical factor affecting the interfacial reliability of thermoelectric(TE)structures.This study investigates the influence of adjoining electrode interactions on the interfacial response of a multi-electrode/TE substrate structure,including interfacial stresses and stress intensity factors at the electrode ends.To solve the corresponding boundary-value problem,the Fourier transforms are adopted to derive a governing integro-differential equation for the interfacial shear stress in multi-electrode systems,incorporating the TE effects as generalized forces on the right-hand side.The results show that both the interfacial tension and transverse stress in the electrodes are significantly affected by the presence of adjacent electrodes.The interaction between neighboring electrodes diminishes as their spacing increases or when an adhesive interlayer is introduced.Furthermore,the softer and thinner electrodes,the softer and thicker adhesive interlayer,and the smaller TE loads are found to be beneficial for improving the interfacial performance.These findings may contribute to the accurate measurement in surface sensors and layout design of multi-point health monitoring systems for TE structures.
文摘Even in small concentrations,toxic metals like lead,cadmium,and mercury are dangerous to the environment and human health.Environmental monitoring depends on precisely identifying these heavy metals,particularly cadmium ions(Cd(Ⅱ)).In this study,we present a novel screen-printed carbon electrode(SPCE)modified with single crystallineα-Fe_(2)O_(3)nano-hexagons that functions as a sensor for detecting Cd(Ⅱ).The performance of the fabricated sensor was thoroughly assessed and compared with unmodified SPCE using the voltammetric method.The crystalline structure of the synthesizedα-Fe_(2)O_(3)nano-hexagons was confirmed through XRD,and surface analysis revealed an average diameter and thickness of 86 nm and 9 nm,respectively.Theα-Fe_(2)O_(3)modified SPCE yields a 7-fold enhanced response(at pH 5.0 vs.Ag/AgCl)to Cd(Ⅱ)than bare SPCE.The modified electrode effectively detects Cd(Ⅱ)with a linear response range of up to 333.0μmol/L and a detection limit of 0.65 nmol/L under ideal circumstances.This newly fabricated sensor offers significant potential for environmental monitoring applications by providing outstanding practicality,anti-interference ability,and repeatability for detecting Cd(Ⅱ)in water samples.
基金part of the ALU-STORE project(Aluminum Metal as Energy Carrier for Seasonal Energy Storage)funded by the KIT Future Fieldsthe research performed at CELEST(Center for Electrochemical Energy Storage Ulm-Karlsruhe)+1 种基金funding from the German Federal Ministry of Research,Technology and Space(BMFTR)in the Nano Mat Futur program(03XP0423)basic funding from the Helmholtz Association。
文摘α-MnO_(2) is a promising,inexpensive,and readily producible catalyst for the oxygen reduction reaction(ORR)in alkaline media,but its application is limited by low electronic conductivity.In this study,we enhance the performance ofα-MnO_(2) electrodes by systematically varying theα-MnO_(2)-to-Vulcan ratio within the catalyst layer.Electrodes are evaluated in a gas diffusion electrode(GDE)half-cell,where an optimized catalyst layer composition leads to significantly improved ORR performance.By finetuning both theα-MnO_(2)-to-Vulcan ratio and theα-MnO_(2) loading,the electrode outperforms a commercial MnO_(2)-based electrode and approaches the performance of the Pt/C benchmark.The improvement is attributed to the presence of a three-dimensional(3D)Vulcan network electronically connecting catalytically activeα-MnO_(2) sites with the substrate.Additionally,the optimized electrodes are employed in a prototype Al-O_(2) flow cell.Under constant oxygen flow,power densities exceed 250 mW cm^(-2),which is significantly higher than that of conventional Al-air batteries.Electrochemical impedance spectroscopy combined with distribution of relaxation times(DRT)analysis enables the separation of anode and cathode charge transfer impedances without the need for an additional reference electrode.The analysis reveals that the anode contributes more than twice as much impedance as the cathode,highlighting the need for further anode optimization.This work demonstrates a transferable approach for catalyst layer screening under technically relevant conditions in the GDE half-cell.Subsequent measurements in an Al-O_(2) flow cell validate the approach.The methodology is widely applicable to the development of advanced electrodes for a variety of metal-air battery technologies.
基金the Natural Sciences and Engineering Research Council of Canada (400705) for funding this study
文摘A sensitive and specific immunosensor for the detection of the hormones cortisol and lactate in human or animal biological fluids, such as sweat and saliva, was devised using the label-free electrochemical chronoamperometric technique. By using these fluids instead of blood,the biosensor becomes noninvasive and is less stressful to the end user, who may be a small child or a farm animal.Electroreduced graphene oxide(e-RGO) was used as a synergistic platform for signal amplification and template for bioconjugation for the sensing mechanism on a screenprinted electrode. The cortisol and lactate antibodies were bioconjugated to the e-RGO using covalent carbodiimide chemistry. Label-free electrochemical chronoamperometric detection was used to analyze the response to the desired biomolecules over the wide detection range. A detection limit of 0.1 ng mL^(-1) for cortisol and 0.1 mM for lactate was established and a correlation between concentration and current was observed. A portable, handheld potentiostat assembled with Bluetooth communication and battery operation enables the developed system for point-of-care applications. A sandwich-like structure containing the sensing mechanisms as a prototype was designed to secure the biosensor to skin and use capillary action to draw sweat or other fluids toward the sensing mechanism. Overall, the immunosensor shows remarkable specificity, sensitivity as well as the noninvasive and point-of-care capabilities and allows the biosensor to be used as a versatile sensing platform in both developed and developing countries.
基金supported by the People Programme(Marie Curie Actions)of the 7th Framework Programme of the European Union(FP7/2007-2013)under the REA grant agreement no.600388(TECNIOspring programme)the Agency for Business Competitiveness of the Government of Catalonia(ACCIO)+1 种基金financial support from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 767678supported by the Fonds voor Wetenschappelijk Onderzoek FWO via project MiCrO2(Grant number G020616N).
文摘are time-consuming and not sensitive enough.However,bacteria typically connect to electrodes through biofilm formation,leading to problems due to lack of uniformity or long device production times.A suitable immobilisation technique can overcome these challenges.Still,they may respond more slowly than biofilm-based electrodes because bacteria gradually adapt to electron transfer during biofilm formation.In this study,we propose a controlled and reproducible way to fabricate bacteria-modified electrodes.The method consists of an immobilisation step using a cellulose matrix,followed by an electrode polarization in the presence of ferricyanide and glucose.Our process is short,reproducible and led us to obtain ready-to-use electrodes featuring a high-current response.An excellent shelf-life of the immobilised electrochemically active bacteria was demonstrated for up to one year.After an initial 50% activity loss in the first month,no further declines have been observed over the following 11 months.We implemented our bacteria-modified electrodes to fabricate a lateral flow platform for toxicity monitoring using formaldehyde(3%).Its addition led to a 59% current decrease approximately 20 min after the toxic input.The methods presented here offer the ability to develop a high sensitivity,easy to produce,and long shelf life bacteria-based toxicity detectors.
文摘The electrochemical oxidation behavior and voltammetric assay of gemifloxacin were investigated using differential-pulse and cyclic voltammetry on a screen-printed carbon electrode.The effects of pH,scan rates,and concentration of the drug on the anodic peak current were studied.Voltammograms of gemifloxacin in Tris-HCl buffer（pH 7.0） exhibited a well-defined single oxidation peak.A differential-pulse voltammetric procedure for the quantitation of gemifloxacin has been developed and suitably validated with respect to linearity,limits of detection and quantification,accuracy,precision,specificity,and robustness.The calibration was linear from 0.5 to 10.0 μM,and the limits of detection and quantification were 0.15 and 5.0 μM.Recoveries ranging from 96.26% to 103.64% were obtained.The method was successfully applied to the determination of gemifloxacin in pharmaceutical tablets without any pre-treatment.Excipients present in the tablets did not interfere in the assay.
基金supported by the Beijing Natural Science Foundation(No.QY24166).
文摘In a pulsed plasma thruster,the voltage distribution between the electrodes is a key factor that influences the ionization process.However,few researchers have conducted in-depth studies of this phenomenon in the past.Reported here are measurements of the voltage distribution between the plates of a parallel-plate pulsed plasma thruster under different discharge voltages,based on which the variations in the total circuit inductance and resistance as well as those between the plates are calculated.The results show that the time-averaged voltage across the plates accounts for 28.7%-50.4%of the capacitor voltage.As the capacitor initial voltage increases from 1250 V to 2000 V,the voltage across the plates rises,but its proportion relative to the capacitor voltage decreases.For every 250 V increase in the capacitor initial voltage,the average voltage proportion across the plates decreases by approximately 2%-3%.Additionally,the voltage proportion decreases gradually from the end near the propellant outward.The voltage distribution ratio between the plates is correlated with the proportions of the resistance and inductance between the plates relative to the total circuit.
基金supported by the National Research Foundation of Korea(NRF)through a grant provided by the Korean government(No.NRF-2021R1F1A1063451).
文摘Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)is a highly successful conductive polymer utilized as an electrode material in energy storage units for portable and wearable electronic de-vices.Nevertheless,employing PEDOT:PSS in supercapacitors(SC)in its pristine state presents challenges due to its suboptimal electrochemical performance and operational instability.To surmount these limita-tions,PEDOT:PSS has been integrated with carbon-based materials to form flexible electrodes,which ex-hibit physical and chemical stability during SC operation.We developed a streamlined fabrication process for high-performance SC electrodes composed of PEDOT:PSS and carbon quantum dots(CQDs).The CQDs were synthesized under microwave irradiation,yielding green-and red-light emissions.Through optimiz-ing the ratios of CQDs to PEDOT:PSS,the SC electrodes were prepared using a spray-coating technique,marking a significant improvement in device performance with a high volumetric capacitance(104.10 F cm-3),impressive energy density(19.68 Wh cm^(-3)),and excellent cyclic stability,retaining~85% of its original volumetric capacitance after 15,000 repeated GCD cycles.Moreover,the SCs,when utilized as a flexible substrate,demonstrated the ability to maintain up to~85% of their electrochemical performance even after 3,000 bending cycles(at a bending angle of 60°).These attributes render this hybrid composite an ideal candidate for a lightweight smart energy storage component in portable and wearable electronic technologies.
文摘This study explores the potential of Michelia champaca wood as a sustainable and locally available precursor for the fabrication of high-performance supercapacitor electrodes.Activated carbons were synthesized through single-step carbonization at 400℃ and 500℃(SSC-400℃ and SSC-500℃) and double-step carbonization at 400℃(DSC-400℃),with all samples activated using H_(3)PO_(4).The effects of carbonization stratergy on the structural,morphological,and electrochemical characteristics of the resulting carbon materials were systematically evaluated,using techniques such as BET,SEM,TEM,XRD,Raman scattering,FTIR,CV,GCD and EIS.Among the samples,SSC-400℃ exhibited the best electrochemical performance,achieving a specific capacitance of 292.2 Fg^(-1),an energy density of 6.4 Wh kg^(-1),and a power density of 198.4 W kg^(-1).This superior performance is attributed to its optimized pore structure,improved sur-face functionality and enhanced conductivity.SSC-500℃showed marginally lower performance,whereas,DSC-400℃ displayed the least favorable results,indicating that double-step carbonization process may negatively affect material quality by disrupting the pore network.This work highlights a strong correlation between synthesis methodology and electrochemical efficiency,directly reinforcing the importance of process optimization in electrode material develop-ment.The findings contribute to the broader goal of developing cost-effective,renewable and environmentally friendly energy storage systems.By valorizing biomass waste,the study supports global movements toward green energy technologies and circular carbon economies,offering a viable pathway for sustainable supercapacitor development and practical applications in energy storage devices.
基金funded by the National Science Centre,Poland,on the basis of the decision number UMO-2020/37/B/ST8/02097supported by the program“Excellence Initiative-Research University”for the AGH University of Krakow(IDUB AGH,No.501.696.7996,Action 4,ID 9880).
文摘Multicomponent Gd_(1−x)Sm_(x)Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)double perovskites are optimized for application in terms of chemical composi-tion and morphology for the use as oxygen electrodes in solid oxide cells.Structural studies of other physicochemical properties are con-ducted on a series of materials obtained by the sol-gel method with different ratios of Gd and Sm cations.It is documented that changing the x value,and the resulting adjustment of the average ionic radius,have a significant impact on the crystal structure,stability,as well as on the total conductivity and thermomechanical properties of the materials,with the best results obtained for the Gd_(0.75)Sm_(0.2)5Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)composition.Oxygen electrodes are prepared using the selected compound,allowing to obtain low polarization resistance values,such as 0.086Ω·cm^(2)at 800℃.Systematic studies of electrocatalytic activity are conducted using La_(0.8)Sr_(0.2)Ga_(0.8)Mg_(_(0.2))O_(3−δ)as the electrolyte for all electrodes,and Ce_(0.8)Gd_(0.2)O_(2−δ)electrolyte for the best performing Gd_(0.75)Sm_(0.2)5Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)electrodes.The electrochemical data are analyzed using the distribution of relaxation times method.Also,the influence of the preparation method of the electrode material is in-ve`stigated using the electrospinning technique.Finally,the performance of the Gd_(0.75)Sm_(0.2)5Ba_(0.5)Sr_(0.5)CoCuO_(5+δ)electrodes is tested in a Ni-YSZ(yttria-stabilized zirconia)anode-supported cell with a Ce_(0.8)Gd_(0.2)O_(2−δ)buffer layer,in the fuel cell and electrolyzer operating modes.With the electrospun electrode,a power density of 462 mW·cm^(−2)is obtained at 700℃,with a current density of ca.0.2 A·cm^(−2)at 1.3 V for the electrolysis at the same temperature,indicating better performance compared to the sol-gel-based electrode.
基金The Open Project of State Key Laboratory of Smart Grid Protection and Operation Control in 2022(No.SGNR0000KJJS2302150).
文摘Fully implanted brain-computer interfaces(BCIs)are preferred as they eliminate signal degradation caused by interference and absorption in external tissues,a common issue in non-fully implanted systems.To optimize the design of electroencephalography electrodes in fully implanted BCI systems,this study investigates the penetration and absorption characteristics of microwave signals in human brain tissue at different frequencies.Electromagnetic simulations are used to analyze the power density distribution and specific absorption rate(SAR)of signals at various frequen-cies.The results indicate that lower-frequency signals offer advantages in terms of power density and attenuation coeffi-cients.However,SAR-normalized analysis,which considers both power density and electromagnetic radiation hazards,shows that higher-frequency signals perform better at superficial to intermediate depths.Specifically,at a depth of 2 mm beneath the cortex,the power density of a 6.5 GHz signal is 247.83%higher than that of a 0.4 GHz signal.At a depth of 5 mm,the power density of a 3.5 GHz signal exceeds that of a 0.4 GHz signal by 224.16%.The findings suggest that 6.5 GHz is optimal for electrodes at a depth of 2 mm,3.5 GHz for 5 mm,2.45 GHz for depths of 15-20 mm,and 1.8 GHz for 25 mm.
文摘Introduction The generation of biological wastes such as cow dung and aloe vera waste(AVW)causes a serious ecological pollution.The microbial electrolytic cell coupled with anaerobic digestion(MEC-AD)system can make a rational utilization of these biodegradable organic wastes,which is of vital importance for alleviating environmental deterioration and reducing resource waste.Electrode materials and accelerants are the two major factors that affect methane production in the MEC-AD system.They affect microbial attachment and electron transfer in the MEC-AD system.Bio-based carbon materials are carbon materials prepared from biomass as raw materials.They have characteristics such as a rich pore structure,good chemical stability,biocompatibility,and controllable surface properties,which can be used as accelerants and electrodes in the MEC-AD system to optimize its performance.This study was to investigate the influence of biomass-derived carbon as an electrode and accelerant on the performance of the MEC-AD system,and the mechanism for increasing the production of biogas and methane was also analyzed,thus providing a basis for the multifunctional application of biomass-derived carbon in the MEC-AD system.Methods A series of experimental methods were adopted to study the MEC-AD system.Two types of bio-based carbon,i.e.,aloe vera waste derived spherical carbon(AVW-SC)and porous carbon(AVW-PC),were synthesized via hydrothermal carbonization.The raw AVW material was washed with water,dried,ground,and subjected to hydrothermal treatment to obtain AVW-SC.After activating AVW-SC with KOH,it was carbonized in a tube furnace to obtain AVW-PC.In the preparation of the electrodes,bio-based carbon(AVW-SC and AVW-PC)was mixed with 5%polytetrafluoroethylene powder in ethanol and deionized water,and then ground in a ball mill for 4 h to form a slurry.The slurry was evenly sprayed on the Ti mesh,dried and sintered in N2 atmosphere at 360℃to obtain Ti-SC and Ti-PC electrodes.Four groups of experiments were conducted to determine the optimal voltage,compare different carbon electrodes,and explore the optimal coating amount.The MEC-AD reactor adopted 500 mL wide-mouthed glass bottles with a working volume of 400 mL.Each MEC-AD system received a co-substrate mixture of cattle dung and aloe vera waste and inoculum of sewage sludge in a mass ratio of 3:7.Afterward,they were placed at(36±1)℃for 35 d.The biogas was collected by a water displacement method.The materials were analyzed by characterization techniques such as X-ray diffraction(XRD)and scanning electron microscopy(SEM),and electrochemical tests were conducted on different electrodes.The composition,pH,TS,VS,TCOD and nutrient content of biogas were analyzed by standard chemical methods.Microbial community analysis was conducted using high-throughput sequencing technology.The modified Gompertz model was adopted to predict the kinetic parameters,and the coulombic efficiency and methane recovery rate were calculated according to a specific formula.Results and discussion The result shows that AVW-SC is spherical and closely aggregated,while AVW-PC has a three-dimensional network structure,with average pore diameter of 9.77 nm.The electron exchange capacity(EEC)of AVW-PC(i.e.,0.75μmol·e-/g)is higher than that of AVW-SC(i.e.,0.15μmol·e-/g),indicating a better electron exchange capacity.These results indicate that AVW-PC provides more substrate and bacteria accumulation sites,and has better electron-donating and electron-accepting ability,thus improving the digestion efficiency.In the MEC-AD system,using Ti mesh as an electrode,the effect of different voltages(i.e.,0,0.4,0.6,0.8 V and 1.2 V)on the system performance is investigated,obtaining the optimum biogas production and organic matter degradation rate at 0.8 V.AVW-SC and AVW-PC are respectively coated on Ti mesh as electrodes.The results show that the MEC-AD system with AVW-PC coated Ti mesh as the electrode has a better performance.The electrochemical analysis shows that the electrode coated with AVW-PC has a larger specific capacitance and a smaller charge transfer resistance,indicating that AVW-PC can improve the electrochemical properties and electron transfer ability of MEC-AD system.The influence of coating amount(i.e.,0.025,0.05,0.10,0.15,and 0.20 g)of AVW-PC on the MEC-AD system is investigated.At a coating amount of AVW-PC of 0.1 g,the cumulative biogas production and methane content of the Ti_(0.8)-PC_90.1) group both reach the maximum values.Different doses of AVW-PC(i.e.,0.10%,0.15%,0.20%,and 0.25%)are added as accelerants in Ti_(0.8)-PC_90.1).At the addition amount of AVW-PC of 0.20%,the Ti_(0.8)-PC_90.1)/PC0.2 group performs the optimum biogas production(i.e.,633.63 mL/g VS),methane content(i.e.,65.85%),and total nutrient content of biogas residue(i.e.,42.30 g/kg).In Ti_(0.8)-PC_90.1)/PC0.2,Bacteroidales,Pseudomonadales,Oscillospirales,Methanobacteraceae,Methanospirillaceae,Methanosarcinacea and Methanosaetaceae significantly increase.The increase in microbial diversity promotes interspecific hydrogen transfer(IHT),interspecific acetic transfer(IAT),and direct interspecific electron transfer(DIET),thereby enhancing methanogenic efficiency.Conclusions AVW-SC and AVW-PC were utilized as electrodes and accelerants to enhance methane yield in MEC-AD system.The Ti mesh electrode coated with different concentrations of AVW-PC achieved the optimal biogas production at 0.8 V.Specifically,the Ti_(0.8)-PC_90.1) combination could generate the maximum total amount of biogas and methane proportion.The Ti_(0.8)-PC_90.1)/PC0.2 combination exhibited the optimum performance(i.e.,biogas yield of 633.63 mL/g VS,methane content of 65.85%and total nutritional content of 42.30 g/kg).High abundances of Bacteroidales,Pseudomonadales,Oscillospirales,Methanobacteraceae,Methanospirillaceae,Methanosarcinaceae,and Methanosaetaceae appeared in the Ti_(0.8)-PC_90.1)/PC0.2 group,compared to other groups.In addition,an increased microbial diversity led to an enhanced methane production through processes like DIET.This research could highlight the potential significance of AVW-PC as both electrode and accelerator for increasing methane production and provide a perspective for improving MEC-AD performance through multiple applications of biomass-derived carbon.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52275425,52405473,and 52405472)the Natural Science Foundation of Guangdong Province(Grant No.2024A1515010993)。
文摘Surgical electrodes are frequently associated with disadvantages such as high surface adhesion and severe thermal damage to adjacent normal tissues,which threaten operation quality and patient safety.In this study,by mimicking the micromorphology and bio-anti-adhesion of shark skin,we proposed a strategy that utilized nanoscale aluminium oxide(Al_(2)O_(3))films deposited on bioinspired shark skin(BSS)microstructures to design a composite surface(Al_(2)O_(3)@BSS)and integrated it into both flat sides of the surgical electrodes.Micro/nano-manufacturing of the Al_(2)O_(3)@BSS surface was sequentially accomplished using nanosecond laser texturing,atomic layer deposition,and low-temperature annealing,endowing it with excellent blood-repellent properties.Visualisation experiments revealed that the tensile stress gradient of the blood coagulum with increasing thickness under a thermal field prompted it to separate from the Al_(2)O_(3)@BSS surface,resulting in anti-adhesion.Furthermore,it was observed for the first time that Al_(2)O_(3) films could transiently excite discharge along a dielectric surface(DADS)to ablate tissues while suppressing Joule heat,thereby minimising thermal damage.A combination of ex vivo tissue and living mouse experiments demonstrated that the Al_(2)O_(3)@BSS electrodes exhibited optimal comprehensive performance in terms of anti-adhesion,damage minimisation,and drag reduction.In addition,the Al_(2)O_(3)@BSS electrodes possessed remarkable antibacterial efficacy against E.coli and S.aureus.The proposed strategy can meet the extreme application requirements of surgical electrodes to improve operation quality and offer valuable insights for future studies.
文摘In order to address the current inability of screen printing to monitor printing pressure online,an online printing pressure monitoring system applied to screen printing machines was designed in this study.In this study,the consistency of printed electrodes was measured by using a confocal microscope and the pressure distribution detected by online pressure monitoring system was compared to investigate the relationship.The results demonstrated the relationship between printing pressure and the consistency of printed electrodes.As printing pressure increases,the ink layer at the corresponding position becomes thicker and that higher printing pressure enhances the consistency of the printed electrodes.The experiment confirms the feasibility of the online pressure monitoring system,which aids in predicting and controlling the consistency of printed electrodes,thereby improving their performance.
