A silver microelectrode with a diameter of 30μm in an aqueous K_(2)SO_(4) electrolyte was irradiated with 55 fs and 213 fs laser pulses.This caused the emission of electrons which transiently charged the electrochemi...A silver microelectrode with a diameter of 30μm in an aqueous K_(2)SO_(4) electrolyte was irradiated with 55 fs and 213 fs laser pulses.This caused the emission of electrons which transiently charged the electrochemical double layer.The two applied pulse durations were significantly shorter than the electron-phonon relaxation time.The laser pulse durations had negligible impact on the emitted charge,which is incompatible with multiphoton emission.On the other hand,the ob-served dependence of emitted charge on laser fluence and electrode potential supports the thermionic emission mechanism.展开更多
This study demonstrates the electrochemical reduction of carbon monoxide(COR)at high current densities in a zero-gap electrolyzer cell and cell stack.By systematically optimizing both the commercially available membra...This study demonstrates the electrochemical reduction of carbon monoxide(COR)at high current densities in a zero-gap electrolyzer cell and cell stack.By systematically optimizing both the commercially available membrane electrode assembly components(including binder content and gas diffusion layer)and the operating conditions,we could perform COR at current densities up to 1.4 A cm^(-2)with a maximum C2+selectivity of 90%.We demonstrated the scale-up to a 3×100 cm^(2)electrolyzer stack that can sustain stable operation at 1 A cm^(-2)for several hours without significant performance decay and with a total C2+selectivity of~80%and an ethylene selectivity of~40%.We provide critical insights into the holistic optimization of key system parameters,without using special catalysts or surface additives,which can pave the way for scalable and industrially viable COR processes.展开更多
Density(p),speed of sound(u),viscosity(η),and refractive index(n_(D))were measured for pure acetonitrile,trichloroethene,and tetrachloroethene,as well as their binary mixtures at temperatures T=(293.15,298.15,303.15)...Density(p),speed of sound(u),viscosity(η),and refractive index(n_(D))were measured for pure acetonitrile,trichloroethene,and tetrachloroethene,as well as their binary mixtures at temperatures T=(293.15,298.15,303.15)K and at ambient pressure(81.5 kPa).From the experimental data,excess molar volume(V_(m)~E),thermal expansion coefficients(α),deviations in isentropic compressibility(Δκ_(S)),viscosity(Δ_η),and refractive index(Δn_(D))were calculated.These values were then correlated using the Redlich-Kister polynomial equation,with fitting coefficients and standard deviations determined.Additionally,the Prigogine-Flory-Patterson(PFP)theory and the Extended Real Associated Solution(ERAS)model were employed to correlate the excess molar volume,while the Perturbed Chain Statistical Associating Fluid Theory(PC-SAFT)was used to predict the density of mixtures.展开更多
Composite microcrystals of the nitramines(NAs)viz.,RDX,HMX,BCHMX,and CL-20 with electrically conductive polyaniline(PANi)are a charge transfer complexes in coagglomerated composite crystals(CACs).The activation energi...Composite microcrystals of the nitramines(NAs)viz.,RDX,HMX,BCHMX,and CL-20 with electrically conductive polyaniline(PANi)are a charge transfer complexes in coagglomerated composite crystals(CACs).The activation energies of thermolysis,E_(a),of the pure NAs and their PANi-CACs were determined using the Kissinger method,and decomposition processes are discussed.Except for the RDX/PANi CACs,all the other CACs show higher E_(a) values for decomposition compared to their pure NA counterparts.For all CACs,relationships are specified between the E_(a) values,on the one hand,and the squares of the detonation velocities,enthalpies of formation,spark energy and impact sensitivities,on the other.The relationships between their low-temperature heats of decomposition,ΔH,from DSC,and their enthalpy of formation,logarithm of impact sensitivity,electric spark energy,as well as detonation energy,are described.The PANi favorably influences the density of the corresponding CACs;surprisingly close linear correlations were found,and explained,between these densities and the E_(a) values.This presence of PANi strongly increased the electrical spark sensitivity of the CACs in comparison to the base NAs.Based on the results obtained,it can be noted in particular the exceptional desensitization of HMX to impact and the increased sensitivity to electrical spark by coating its crystals with polyaniline.展开更多
Dielectric ceramics with ultrahigh power density and ultrafast charge/discharge rates are crucial components of advanced dielectric capacitors. However, enhancing their comprehensive performance remains a major challe...Dielectric ceramics with ultrahigh power density and ultrafast charge/discharge rates are crucial components of advanced dielectric capacitors. However, enhancing their comprehensive performance remains a major challenge for cutting-edge applications. Here, a high-entropy strategy is proposed to construct multiple local distortions, including various types of oxygen octahedral tilts, highly dynamic polar nanoregions, and lattice distortions. This approach effectively delays polarization saturation, reduces energy loss, and, in conjunction with the ultrafine grains induced by the high-entropy effect, enhances mechanical properties and breakdown field. Therefore, a remarkable recoverable energy density of 9.1 J cm-3, a high conversion efficiency of 82.7 %, and a large Vickers hardness of 8.77 GPa are simultaneously achieved in 0.73Bi_(0.47)Na_(0.47)Ba_(0.06)TiO_(3)-0.27Ca_(0.7)La_(0.2)Zr_(0.15)Ti_(0.85)O_(3) lead-free high-entropy relaxors. Additionally, superior frequency and temperature stability, as well as excellent charge/discharge performance, are also obtained. These findings demonstrate that the high-entropy strategy is a promising method for designing high-performance dielectric ceramics.展开更多
Photoelectrochemistry is a promising method for the direct conversion of sunlight into valuable chemicals by combining the functions of solar panels and electrolyzers in one technology.In most studies,semiconductor/ca...Photoelectrochemistry is a promising method for the direct conversion of sunlight into valuable chemicals by combining the functions of solar panels and electrolyzers in one technology.In most studies,semiconductor/catalyst photoelectrode assemblies are used to achieve reasonable efficiencies.At the same time,unlike in dark electrochemical processes,the role of the catalyst is not straightforward in photoelectrochemistry,where the onset potential of the redox process should be mostly determined by the flatband potential of the semiconductor.In addition,the energy of holes(i.e.,the surface potential)is independent of the applied bias;it is defined by the valence band(VB)position.In this study,we compared PdAu,Au,and Ni on Si photoanodes in the photoelectrochemical(PEC)oxidation of glycerol at record high current densities(>180 mA cm^(‒2)),coupled to H_(2) evolution at the cathode.We successfully decreased the energy requirement(i.e.,the cell voltage)of the paired conversion of glycerol and water by 0.7 V by exchanging the widely studied Ni catalyst with PdAu.The catalyst choice also dictates the product distribution,resulting mainly in C3 products on PdAu,glycolate(C2 product)on Au,and formate(C1 product)on Ni,without complete mineralization of glycerol(CO_(2) formation)that is difficult to rule out in dark electrochemical processes(as demonstrated by comparative measurements).Finally,we achieved a bias‐free(standalone)operation with PdAu/Si and Au/Si photoanodes by combining the PEC oxidation of glycerol with oxygen reduction reaction(ORR).展开更多
The development of actuators based on ionic polymers as soft robotics,artificial muscles,and sensors is currently considered one of the most urgent topics.They are lightweight materials,in addition to their high effic...The development of actuators based on ionic polymers as soft robotics,artificial muscles,and sensors is currently considered one of the most urgent topics.They are lightweight materials,in addition to their high efficiency,and they can be controlled by a low power source.Nevertheless,the most popular ionic polymers are derived from fossil-based resources.Hence,it is now deemed crucial to produce these actuators using sustainable materials.In this review,the use of ionic polymeric materials as actuators is reviewed through the emphasis on their role in the domain of renewablematerials.The reviewencompasses recent advancements inmaterial formulation and performance enhancement,alongside a comparative analysis with conventional actuator systems.It was found that renewable polymeric actuators based on ionic gels and conductive polymers are easier to prepare compared to ionic polymermetal composites.In addition,the proportion of actuator manufacturing utilizing renewable materials rose to 90%,particularly for ion gel actuators,which was related to the possibility of using renewable polymers as ionic or conductive substances.Moreover,the possible improvements in biopolymeric actuators will experience an annual rise of at least 10%over the next decade,correlating with the growth of their market,which aligns with the worldwide goal of reducing global warming.Additionally,compared to fossil-derived polymers,the decomposition rate of renewable materials reaches 100%,while biodegradable fossil-based substances can exceed 60%within several weeks.Ultimately,this review aims to elucidate the potential of ionic polymeric materials as a viable and sustainable solution for future actuator technologies.展开更多
Kinetics of the gas-phase reactions of•OH radicals with a series of fluoroesters were studied for the first time at 298±3 K and atmospheric pressure.Relative rate coefficients were determined by in situ FTIR spec...Kinetics of the gas-phase reactions of•OH radicals with a series of fluoroesters were studied for the first time at 298±3 K and atmospheric pressure.Relative rate coefficients were determined by in situ FTIR spectroscopy in nitrogen and GC-FID in air to monitor the decay of reactants and references.The following coefficient values(in 10^(−12)cm^(3)/(molecule•sec))were obtained for ethyl fluoroacetate(EFA),ethyl 4,4,4-trifluorobutyrate(ETB),and butyl fluoroacetate(BFA),respectively:k_(1)(EFA+OH)=1.15±0.25 by FTIR and 1.34±0.23 by GC-FID;k_(2)(ETB+OH)=1.61±0.36 by FTIR and 2.02±0.30 by GC-FID;k_(3)(BFA+OH)=2.24±0.37 by FTIR.Reactivity trends were developed and correlated with the number of CH_(3)and F substituents in the fluoroester,and structure-activity relationships(SARs)calculations were performed.In addition,the tropospheric lifetimes of EFA,ETB,and BFA upon degradation by OH radicals were calculated to be 9,6,and 5 days,respectively,indicating that these fluorinated compounds could have a possible regional effect from the emission source.Relatively small photochemical ozone creation potentials of 9,7,and 19 were estimated for EFA,ETB,and BFA,respectively.The GlobalWarming Potentials(GWPs)for EFA,ETB,and BFA were calculated for different time horizons.For a 20-year time horizon,the GWPs were 1.393,0.063,and 0.062,respectively.In the case of a 100-year time horizon,the GWPs were 0.379,0.017,and 0.017,and for a 500-year time horizon,the GWPs were 0.108,0.005,and 0.005 for EFA,ETB,and BFA.展开更多
The selection of carbon sources and the biosynthesis of polyhydroxybutyrate(PHB)by the Azotobacter vinelandii N-15 strain using renewable raw materials were investigated.Among the tested substrates(starch,sucrose,mola...The selection of carbon sources and the biosynthesis of polyhydroxybutyrate(PHB)by the Azotobacter vinelandii N-15 strain using renewable raw materials were investigated.Among the tested substrates(starch,sucrose,molasses,bran),molasses as the carbon source yielded the highest PHB production.The maximum polymer yield(26%of dry biomass)was achieved at a molasses concentration of 40 g/L.PHB formation was confirmed via thinlayer chromatography,gas chromatography and Fourier transform infrared spectroscopy.Composite films based on PHB,polylactic acid(PLA),and their blends were fabricated using the solvent casting.The biodegradation of these films was studied with bacteria isolated from plastic-contaminated soil.These bacteria utilized the biopolymers as their sole carbon source,with the biodegradation process lasting three months.Structural and chemical changes in the films were analyzed using FTIR spectroscopy,differential scanning calorimetry,and thermogravimetry.Among the microorganisms used to study the biodegradation of PHB,PLA,and their blends,Streptomyces sp.K2 and Streptomyces sp.K4 exhibited the highest biodegradation efficiency.PHB-containing films demonstrated significant advantages over other biodegradable polymers,as they degrade under aerobic conditions via enzymatic hydrolysis using microbial depolymerases.展开更多
As a promising optical and piezoelectric crystal,efficient growth of LGN single crystal is crucial for its practical applications.Herein,a langanite(La_(3)Ga_(5.5)Nb_(0.5)O_(14),LGN)crystal with high quality was succe...As a promising optical and piezoelectric crystal,efficient growth of LGN single crystal is crucial for its practical applications.Herein,a langanite(La_(3)Ga_(5.5)Nb_(0.5)O_(14),LGN)crystal with high quality was successfully grown by the Bridgman method along the Z direction.In order to prepare high-purity polycrystalline precursors for LGN crystal growth,the sintering conditions of LGN polycrystalline precursors were studied in detail.The melting point of LGN was also measured to provide a reference for the crystal growth temperature.For the[001]oriented wafer,the full width at half maximum(EWHM)value of the nigh-resolution X-ray diffraction(HRXRD)analysis is 38.52",demonstrating that the LGN crystal exhibits excellent crystalline quality.In addition,we also measured the thermal properties and transmission spectrum of the as-grown LGN crystal.It is found that the absorption peak at 1.85μm of the LGN crystal grown in air using the Bridgman method disappears compared with previous reports(grown in N_(2+)(1-3)vol%O_(2)atmosphere),which is attributed to the oxygen-enriched growth environment.Similar phenomenon also occurs in other LGS-type disordered crystals.It is believed that these findings may expand the potential applications of LGS series crystals at 1.85μm.展开更多
Hydrophilicity is critical in Nafion membranes during fuel cell operation as insufficient membrane hydration leads to brittle behavior and a drop in proton conductivity.The incorporation of APTS(3-(aminopro pyl)trieth...Hydrophilicity is critical in Nafion membranes during fuel cell operation as insufficient membrane hydration leads to brittle behavior and a drop in proton conductivity.The incorporation of APTS(3-(aminopro pyl)triethoxysilane)into exfoliated graphene oxide(EGO)by covalent functionalization to be used as filler into Nafion membranes allows higher hydrophilicity for these membranes.This is associated with promoting hydroxyl,carbonyl,siloxane,silane,and amine groups within the EGO-APTS matrix.The incorporation of these materials as Fuel Cell MEAs leads to a significant reduction of the ohmic resistance measured at high frequency resistance(HFR)in electrochemical impedance spectroscopy(EIS)experiments and achieves maximum power densities of 1.33 W cm^(-2)at 60℃ at 100%RH(APTS-EGO,0.2 wt%)and1.33 W cm^(-2)at 60℃ at 70%RH(APTS-EGO,0.3 wt%),which represents an improvement of 190%compared to the commercial Nafion 212 when utilizing low humidification conditions(70%).Moreover,the as-synthesized membrane utilizes lower Nafion ionomer mass,which,in conjunction with the excellent cell performance,has the potential to decrease the cost of the membrane from 87 to 80￡/W as well as a reduction of fluorinated compounds within the membrane.展开更多
The therapeutic efficacy of cuproptosis,ferroptosis,and apoptosis is hindered by inadequate intracellular copper and iron levels,hypoxia,and elevated glutathione(GSH)expression in tumor cells.Thermoelectric technology...The therapeutic efficacy of cuproptosis,ferroptosis,and apoptosis is hindered by inadequate intracellular copper and iron levels,hypoxia,and elevated glutathione(GSH)expression in tumor cells.Thermoelectric technology is an emerging frontier in medical therapy that aims to achieve efficient thermal and electrical transport characteristics within a narrow thermal range for biological systems.Here,we systematically constructed biodegradable Cu_(2)MnS_(3-x)-PEG/glucose oxidase(MCPG)with sulfur vacancies(S_(V))using photothermoelectric catalysis(PTEC),photothermal-enhanced enzyme catalysis,and starvation therapy.This triggers GSH consumption and disrupts intracellular redox homeostasis,leading to immunogenic cell death.Under 1064 nm laser irradiation,MCPG enriched with S_(V),owing to doping,generates a local temperature gradient that activates PTEC and produces toxic reactive oxygen species(ROS).Hydroxyl radicals and oxygen are generated through peroxide and catalase-like processes.Increased oxygen levels alleviate tumor hypoxia,whereas hydrogen peroxide production from glycometabolism provides sufficient ROS for a cascade catalytic reaction,establishing a self-reinforcing positive mechanism.Density functional theory calculations demonstrated that vacancy defects effectively enhanced enzyme catalytic activity.Multimodal imaging-guided synergistic therapy not only damages tumor cells,but also elicits an antitumor immune response to inhibit tumor metastasis.This study offers novel insights into the cuproptosis/ferroptosis/apoptosis pathways of Cu-based PTEC nanozymes.展开更多
The behaviors of La and Ce on gram boundaries in carbon manganese clean steel were investigated by high-reso- lution transmission elecetron microscope （HRTEM）, scanning elecetron microscopy（SEM ）, energy dispersiv...The behaviors of La and Ce on gram boundaries in carbon manganese clean steel were investigated by high-reso- lution transmission elecetron microscope （HRTEM）, scanning elecetron microscopy（SEM ）, energy dispersive spectrometer （EDS） and X-ray diffraction（XRD） analysis. The existing forms of rare earths （RE） in clean steel were as follows： dissolved in sohd solution, forming inclusion or second phase containing RE （RE-Fe-P, La-P, Fe-La eutectic and Fe-Ce phase）. The dissolved La or Ce segregated at grain boundaries. The segregation of both S and P at gram boundaries was reduced with suitable RE content. The impact toughness of the steel was improved obviously. La and Ce had effecets on purifying molten steel and modifying inclusions in clean steel, whereas with excessive La or Ce, La-Fe-P, La-P and Fe-La eutecetic phase or Ce-Fe-P and Fe-Ce intermetallic compound would form along grain boundaries, causing the impact energy to decrease significantly.展开更多
The effects of Ce addition on the quantity, size, distribution of inclusions and the content of oxygen, sulfur and other hazardous residual elements in spring steel used as fastener in high speed railway were investig...The effects of Ce addition on the quantity, size, distribution of inclusions and the content of oxygen, sulfur and other hazardous residual elements in spring steel used as fastener in high speed railway were investigated by metallographic examination, SEM-EDS and composition analysis. The results indicated that the contents of oxygen decreased with the addition of Ce （[Ce]〈0.1%） and the content of sulfur continually decreased with increasing content of Ce （[Ce]〈1.2%）. However, with the further increase of Ce element addition, the content of [O] and T[O] began to increase. The content of Ce corresponding to the lowest [O] and T[O] lied in the range of 0.10%-0.13%and 0.045%-0.065%, respectively. The addition of Ce in spring steel resulted in the formation of rare earth oxides/oxysulfides and decreased the size of inclusions to less than 3μm in globular or spheroid shape. Moreover, the residual harmful elements （As, P, Pb and Sn） were found to exist in the Ce-containing inclusions, which had proved that the Ce addition could capture the residual elements and suppress their precipitation behaviors in the grain boundary.展开更多
文摘A silver microelectrode with a diameter of 30μm in an aqueous K_(2)SO_(4) electrolyte was irradiated with 55 fs and 213 fs laser pulses.This caused the emission of electrons which transiently charged the electrochemical double layer.The two applied pulse durations were significantly shorter than the electron-phonon relaxation time.The laser pulse durations had negligible impact on the emitted charge,which is incompatible with multiphoton emission.On the other hand,the ob-served dependence of emitted charge on laser fluence and electrode potential supports the thermionic emission mechanism.
基金Nemzeti Kutatási Fejlesztésiés Innovációs Hivatal,Grant/Award Number:RRF-2.3.1-21-2022-00009Horizon 2020 Framework Programme,Grant/Award Number:862453。
文摘This study demonstrates the electrochemical reduction of carbon monoxide(COR)at high current densities in a zero-gap electrolyzer cell and cell stack.By systematically optimizing both the commercially available membrane electrode assembly components(including binder content and gas diffusion layer)and the operating conditions,we could perform COR at current densities up to 1.4 A cm^(-2)with a maximum C2+selectivity of 90%.We demonstrated the scale-up to a 3×100 cm^(2)electrolyzer stack that can sustain stable operation at 1 A cm^(-2)for several hours without significant performance decay and with a total C2+selectivity of~80%and an ethylene selectivity of~40%.We provide critical insights into the holistic optimization of key system parameters,without using special catalysts or surface additives,which can pave the way for scalable and industrially viable COR processes.
基金Bu-Ali Sina University for providing financial support for conducting this study。
文摘Density(p),speed of sound(u),viscosity(η),and refractive index(n_(D))were measured for pure acetonitrile,trichloroethene,and tetrachloroethene,as well as their binary mixtures at temperatures T=(293.15,298.15,303.15)K and at ambient pressure(81.5 kPa).From the experimental data,excess molar volume(V_(m)~E),thermal expansion coefficients(α),deviations in isentropic compressibility(Δκ_(S)),viscosity(Δ_η),and refractive index(Δn_(D))were calculated.These values were then correlated using the Redlich-Kister polynomial equation,with fitting coefficients and standard deviations determined.Additionally,the Prigogine-Flory-Patterson(PFP)theory and the Extended Real Associated Solution(ERAS)model were employed to correlate the excess molar volume,while the Perturbed Chain Statistical Associating Fluid Theory(PC-SAFT)was used to predict the density of mixtures.
基金funding from the Student Grant Project no.SGS_2022_003 of the Faculty of Chemical Technology at the University of Pardubice Czechia.
文摘Composite microcrystals of the nitramines(NAs)viz.,RDX,HMX,BCHMX,and CL-20 with electrically conductive polyaniline(PANi)are a charge transfer complexes in coagglomerated composite crystals(CACs).The activation energies of thermolysis,E_(a),of the pure NAs and their PANi-CACs were determined using the Kissinger method,and decomposition processes are discussed.Except for the RDX/PANi CACs,all the other CACs show higher E_(a) values for decomposition compared to their pure NA counterparts.For all CACs,relationships are specified between the E_(a) values,on the one hand,and the squares of the detonation velocities,enthalpies of formation,spark energy and impact sensitivities,on the other.The relationships between their low-temperature heats of decomposition,ΔH,from DSC,and their enthalpy of formation,logarithm of impact sensitivity,electric spark energy,as well as detonation energy,are described.The PANi favorably influences the density of the corresponding CACs;surprisingly close linear correlations were found,and explained,between these densities and the E_(a) values.This presence of PANi strongly increased the electrical spark sensitivity of the CACs in comparison to the base NAs.Based on the results obtained,it can be noted in particular the exceptional desensitization of HMX to impact and the increased sensitivity to electrical spark by coating its crystals with polyaniline.
基金supported by the National Natural Science Foundation of China(No.52102129)the Hunan Provin-cial Natural Science Foundation of China(No.2023JJ30138)the Science and Technology Innovation Program of Hunan Province(2023RC3094).
文摘Dielectric ceramics with ultrahigh power density and ultrafast charge/discharge rates are crucial components of advanced dielectric capacitors. However, enhancing their comprehensive performance remains a major challenge for cutting-edge applications. Here, a high-entropy strategy is proposed to construct multiple local distortions, including various types of oxygen octahedral tilts, highly dynamic polar nanoregions, and lattice distortions. This approach effectively delays polarization saturation, reduces energy loss, and, in conjunction with the ultrafine grains induced by the high-entropy effect, enhances mechanical properties and breakdown field. Therefore, a remarkable recoverable energy density of 9.1 J cm-3, a high conversion efficiency of 82.7 %, and a large Vickers hardness of 8.77 GPa are simultaneously achieved in 0.73Bi_(0.47)Na_(0.47)Ba_(0.06)TiO_(3)-0.27Ca_(0.7)La_(0.2)Zr_(0.15)Ti_(0.85)O_(3) lead-free high-entropy relaxors. Additionally, superior frequency and temperature stability, as well as excellent charge/discharge performance, are also obtained. These findings demonstrate that the high-entropy strategy is a promising method for designing high-performance dielectric ceramics.
基金funding under the European Union's Horizon Europe research and innovation program from the European Research Council(ERC,Grant Agreement No.101043617)(C.J.).Project No.RRF‐2.3.1‐21‐2022‐00009titled National Laboratory for Renewable Energy,was implemented with the support provided by the Recovery and Resilience Facility of the European Union within the framework of the Program Széchenyi Plan Plus(C.J.)support from MICIU/AEI/10.13039/501100011033/(PID2020-116093RB−C41 and PID2023‐152771OB‐I00).European Innovation Council(EIC)(101071010).
文摘Photoelectrochemistry is a promising method for the direct conversion of sunlight into valuable chemicals by combining the functions of solar panels and electrolyzers in one technology.In most studies,semiconductor/catalyst photoelectrode assemblies are used to achieve reasonable efficiencies.At the same time,unlike in dark electrochemical processes,the role of the catalyst is not straightforward in photoelectrochemistry,where the onset potential of the redox process should be mostly determined by the flatband potential of the semiconductor.In addition,the energy of holes(i.e.,the surface potential)is independent of the applied bias;it is defined by the valence band(VB)position.In this study,we compared PdAu,Au,and Ni on Si photoanodes in the photoelectrochemical(PEC)oxidation of glycerol at record high current densities(>180 mA cm^(‒2)),coupled to H_(2) evolution at the cathode.We successfully decreased the energy requirement(i.e.,the cell voltage)of the paired conversion of glycerol and water by 0.7 V by exchanging the widely studied Ni catalyst with PdAu.The catalyst choice also dictates the product distribution,resulting mainly in C3 products on PdAu,glycolate(C2 product)on Au,and formate(C1 product)on Ni,without complete mineralization of glycerol(CO_(2) formation)that is difficult to rule out in dark electrochemical processes(as demonstrated by comparative measurements).Finally,we achieved a bias‐free(standalone)operation with PdAu/Si and Au/Si photoanodes by combining the PEC oxidation of glycerol with oxygen reduction reaction(ORR).
基金funded by the Russian Science Foundation(RSF),grantNo.24-23-00558,https://rscf.ru/en/project/24-23-00558/(accessed on 04 February 2025).
文摘The development of actuators based on ionic polymers as soft robotics,artificial muscles,and sensors is currently considered one of the most urgent topics.They are lightweight materials,in addition to their high efficiency,and they can be controlled by a low power source.Nevertheless,the most popular ionic polymers are derived from fossil-based resources.Hence,it is now deemed crucial to produce these actuators using sustainable materials.In this review,the use of ionic polymeric materials as actuators is reviewed through the emphasis on their role in the domain of renewablematerials.The reviewencompasses recent advancements inmaterial formulation and performance enhancement,alongside a comparative analysis with conventional actuator systems.It was found that renewable polymeric actuators based on ionic gels and conductive polymers are easier to prepare compared to ionic polymermetal composites.In addition,the proportion of actuator manufacturing utilizing renewable materials rose to 90%,particularly for ion gel actuators,which was related to the possibility of using renewable polymers as ionic or conductive substances.Moreover,the possible improvements in biopolymeric actuators will experience an annual rise of at least 10%over the next decade,correlating with the growth of their market,which aligns with the worldwide goal of reducing global warming.Additionally,compared to fossil-derived polymers,the decomposition rate of renewable materials reaches 100%,while biodegradable fossil-based substances can exceed 60%within several weeks.Ultimately,this review aims to elucidate the potential of ionic polymeric materials as a viable and sustainable solution for future actuator technologies.
文摘Kinetics of the gas-phase reactions of•OH radicals with a series of fluoroesters were studied for the first time at 298±3 K and atmospheric pressure.Relative rate coefficients were determined by in situ FTIR spectroscopy in nitrogen and GC-FID in air to monitor the decay of reactants and references.The following coefficient values(in 10^(−12)cm^(3)/(molecule•sec))were obtained for ethyl fluoroacetate(EFA),ethyl 4,4,4-trifluorobutyrate(ETB),and butyl fluoroacetate(BFA),respectively:k_(1)(EFA+OH)=1.15±0.25 by FTIR and 1.34±0.23 by GC-FID;k_(2)(ETB+OH)=1.61±0.36 by FTIR and 2.02±0.30 by GC-FID;k_(3)(BFA+OH)=2.24±0.37 by FTIR.Reactivity trends were developed and correlated with the number of CH_(3)and F substituents in the fluoroester,and structure-activity relationships(SARs)calculations were performed.In addition,the tropospheric lifetimes of EFA,ETB,and BFA upon degradation by OH radicals were calculated to be 9,6,and 5 days,respectively,indicating that these fluorinated compounds could have a possible regional effect from the emission source.Relatively small photochemical ozone creation potentials of 9,7,and 19 were estimated for EFA,ETB,and BFA,respectively.The GlobalWarming Potentials(GWPs)for EFA,ETB,and BFA were calculated for different time horizons.For a 20-year time horizon,the GWPs were 1.393,0.063,and 0.062,respectively.In the case of a 100-year time horizon,the GWPs were 0.379,0.017,and 0.017,and for a 500-year time horizon,the GWPs were 0.108,0.005,and 0.005 for EFA,ETB,and BFA.
基金financial support of this paper by the Ministry of Education and Science of Ukraine under grant(Biotherm/0124U000789).
文摘The selection of carbon sources and the biosynthesis of polyhydroxybutyrate(PHB)by the Azotobacter vinelandii N-15 strain using renewable raw materials were investigated.Among the tested substrates(starch,sucrose,molasses,bran),molasses as the carbon source yielded the highest PHB production.The maximum polymer yield(26%of dry biomass)was achieved at a molasses concentration of 40 g/L.PHB formation was confirmed via thinlayer chromatography,gas chromatography and Fourier transform infrared spectroscopy.Composite films based on PHB,polylactic acid(PLA),and their blends were fabricated using the solvent casting.The biodegradation of these films was studied with bacteria isolated from plastic-contaminated soil.These bacteria utilized the biopolymers as their sole carbon source,with the biodegradation process lasting three months.Structural and chemical changes in the films were analyzed using FTIR spectroscopy,differential scanning calorimetry,and thermogravimetry.Among the microorganisms used to study the biodegradation of PHB,PLA,and their blends,Streptomyces sp.K2 and Streptomyces sp.K4 exhibited the highest biodegradation efficiency.PHB-containing films demonstrated significant advantages over other biodegradable polymers,as they degrade under aerobic conditions via enzymatic hydrolysis using microbial depolymerases.
基金Project supported by the National Key R&D Program of China(2022YFB3204000)National Natural Science Foundation of China(51832009)。
文摘As a promising optical and piezoelectric crystal,efficient growth of LGN single crystal is crucial for its practical applications.Herein,a langanite(La_(3)Ga_(5.5)Nb_(0.5)O_(14),LGN)crystal with high quality was successfully grown by the Bridgman method along the Z direction.In order to prepare high-purity polycrystalline precursors for LGN crystal growth,the sintering conditions of LGN polycrystalline precursors were studied in detail.The melting point of LGN was also measured to provide a reference for the crystal growth temperature.For the[001]oriented wafer,the full width at half maximum(EWHM)value of the nigh-resolution X-ray diffraction(HRXRD)analysis is 38.52",demonstrating that the LGN crystal exhibits excellent crystalline quality.In addition,we also measured the thermal properties and transmission spectrum of the as-grown LGN crystal.It is found that the absorption peak at 1.85μm of the LGN crystal grown in air using the Bridgman method disappears compared with previous reports(grown in N_(2+)(1-3)vol%O_(2)atmosphere),which is attributed to the oxygen-enriched growth environment.Similar phenomenon also occurs in other LGS-type disordered crystals.It is believed that these findings may expand the potential applications of LGS series crystals at 1.85μm.
基金financially supported by the UK Research Council EPRSC EP/W03395X/1the Program grant SynHiSel EP/V047078/1the Hydrogen and Fuel Cells Hub(H_(2)FC SUPERGEN)EP/P024807/1。
文摘Hydrophilicity is critical in Nafion membranes during fuel cell operation as insufficient membrane hydration leads to brittle behavior and a drop in proton conductivity.The incorporation of APTS(3-(aminopro pyl)triethoxysilane)into exfoliated graphene oxide(EGO)by covalent functionalization to be used as filler into Nafion membranes allows higher hydrophilicity for these membranes.This is associated with promoting hydroxyl,carbonyl,siloxane,silane,and amine groups within the EGO-APTS matrix.The incorporation of these materials as Fuel Cell MEAs leads to a significant reduction of the ohmic resistance measured at high frequency resistance(HFR)in electrochemical impedance spectroscopy(EIS)experiments and achieves maximum power densities of 1.33 W cm^(-2)at 60℃ at 100%RH(APTS-EGO,0.2 wt%)and1.33 W cm^(-2)at 60℃ at 70%RH(APTS-EGO,0.3 wt%),which represents an improvement of 190%compared to the commercial Nafion 212 when utilizing low humidification conditions(70%).Moreover,the as-synthesized membrane utilizes lower Nafion ionomer mass,which,in conjunction with the excellent cell performance,has the potential to decrease the cost of the membrane from 87 to 80￡/W as well as a reduction of fluorinated compounds within the membrane.
基金supported by the National Natural Science Foundation of China(NSFC 52002091,U22A20347,and 52102344)Heilongjiang Natural Science Foundation Project of Outstanding Youth Project(YQ2023B005)+1 种基金China Postdoctoral Science Foundation(2023T160154)the Fundamental Research Funds for the Central Universities。
文摘The therapeutic efficacy of cuproptosis,ferroptosis,and apoptosis is hindered by inadequate intracellular copper and iron levels,hypoxia,and elevated glutathione(GSH)expression in tumor cells.Thermoelectric technology is an emerging frontier in medical therapy that aims to achieve efficient thermal and electrical transport characteristics within a narrow thermal range for biological systems.Here,we systematically constructed biodegradable Cu_(2)MnS_(3-x)-PEG/glucose oxidase(MCPG)with sulfur vacancies(S_(V))using photothermoelectric catalysis(PTEC),photothermal-enhanced enzyme catalysis,and starvation therapy.This triggers GSH consumption and disrupts intracellular redox homeostasis,leading to immunogenic cell death.Under 1064 nm laser irradiation,MCPG enriched with S_(V),owing to doping,generates a local temperature gradient that activates PTEC and produces toxic reactive oxygen species(ROS).Hydroxyl radicals and oxygen are generated through peroxide and catalase-like processes.Increased oxygen levels alleviate tumor hypoxia,whereas hydrogen peroxide production from glycometabolism provides sufficient ROS for a cascade catalytic reaction,establishing a self-reinforcing positive mechanism.Density functional theory calculations demonstrated that vacancy defects effectively enhanced enzyme catalytic activity.Multimodal imaging-guided synergistic therapy not only damages tumor cells,but also elicits an antitumor immune response to inhibit tumor metastasis.This study offers novel insights into the cuproptosis/ferroptosis/apoptosis pathways of Cu-based PTEC nanozymes.
基金Project supported by the Ministry of Science and Technology of China (2002BA315A-5)
文摘The behaviors of La and Ce on gram boundaries in carbon manganese clean steel were investigated by high-reso- lution transmission elecetron microscope （HRTEM）, scanning elecetron microscopy（SEM ）, energy dispersive spectrometer （EDS） and X-ray diffraction（XRD） analysis. The existing forms of rare earths （RE） in clean steel were as follows： dissolved in sohd solution, forming inclusion or second phase containing RE （RE-Fe-P, La-P, Fe-La eutectic and Fe-Ce phase）. The dissolved La or Ce segregated at grain boundaries. The segregation of both S and P at gram boundaries was reduced with suitable RE content. The impact toughness of the steel was improved obviously. La and Ce had effecets on purifying molten steel and modifying inclusions in clean steel, whereas with excessive La or Ce, La-Fe-P, La-P and Fe-La eutecetic phase or Ce-Fe-P and Fe-Ce intermetallic compound would form along grain boundaries, causing the impact energy to decrease significantly.
基金supported by National Natural Science Foundation of China(5110401351174022)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry(44),Beijing Higher Education Young Elite Teacher Project(0349)
文摘The effects of Ce addition on the quantity, size, distribution of inclusions and the content of oxygen, sulfur and other hazardous residual elements in spring steel used as fastener in high speed railway were investigated by metallographic examination, SEM-EDS and composition analysis. The results indicated that the contents of oxygen decreased with the addition of Ce （[Ce]〈0.1%） and the content of sulfur continually decreased with increasing content of Ce （[Ce]〈1.2%）. However, with the further increase of Ce element addition, the content of [O] and T[O] began to increase. The content of Ce corresponding to the lowest [O] and T[O] lied in the range of 0.10%-0.13%and 0.045%-0.065%, respectively. The addition of Ce in spring steel resulted in the formation of rare earth oxides/oxysulfides and decreased the size of inclusions to less than 3μm in globular or spheroid shape. Moreover, the residual harmful elements （As, P, Pb and Sn） were found to exist in the Ce-containing inclusions, which had proved that the Ce addition could capture the residual elements and suppress their precipitation behaviors in the grain boundary.
