A new air exchange rate （AER） monitoring method using continuous CO2 sensors was developed and validated through both laboratory experiments and field studies. Controlled laboratory simulation tests were conducted i...A new air exchange rate （AER） monitoring method using continuous CO2 sensors was developed and validated through both laboratory experiments and field studies. Controlled laboratory simulation tests were conducted in a 1-m3 environmental chamber at different AERs （0.1-10.0 hr-1）. AERs were determined using the decay method based on box model assumptions. Field tests were conducted in classrooms, dormitories, meeting rooms and apartments during 2-5 weekdays using CO2 sensors coupled with data loggers. Indoor temperature, relative humidity （RH）, and CO2 concentrations were continuously monitored while outdoor parameters combined with on-site climate conditions were recorded. Statistical results indicated that good laboratory performance was achieved： duplicate precision was within 10%, and the measured AERs were 90%-120% of the real AERs. Average AERs were 1.22, 1.37, 1.10, 1.91 and 0.73 hr-l in dormitories, air-conditioned classrooms, classrooms with an air circulation cooling system, reading rooms, and meeting rooms, respectively. In an elderly particulate matter exposure study, all the homes had AER values ranging from 0.29 to 3.46 hr-1 in fall, and 0.12 to 1.39 hr-1 in winter with a median AER of 1.15.展开更多
A type of CO2 sensor based on oxygen concentration cell was designed as following: Cell I: Pt | Au, O2, CO2| Na2CO3(Au)|NKBA(Au)|YSZ|O2, CO2|Pt or Cell lI: Pt|Au, O2, CO2|K2CO3(Au)|NKBA(Au)|YSZ|O2, CO2|Pt. (Na,K-β/β...A type of CO2 sensor based on oxygen concentration cell was designed as following: Cell I: Pt | Au, O2, CO2| Na2CO3(Au)|NKBA(Au)|YSZ|O2, CO2|Pt or Cell lI: Pt|Au, O2, CO2|K2CO3(Au)|NKBA(Au)|YSZ|O2, CO2|Pt. (Na,K-β/β'-AI2O3 is named by NKBA). The sensor signal is consistent with the Nernstian slope within the region of phase equilibrium for Na, K-β/β'-AI2O3 material. The relationship between CO2 sensor voltage response and phase equilibrium of solid electrolyte Na, K-β/β-AI2O3 is discussed in this paper.展开更多
The application of NO_(2)sensor reduces the emission of NO_(2)from the industry and automotive vehicles.However,insufficient electrocatalytic activity and adsorption to NO_(2)of sensing electrode(SE)limit the sensitiv...The application of NO_(2)sensor reduces the emission of NO_(2)from the industry and automotive vehicles.However,insufficient electrocatalytic activity and adsorption to NO_(2)of sensing electrode(SE)limit the sensitivity increment of NO_(2)sensor.Thus,a novel ZnWO_(4)/Li_(6)W_(2)O_(9)heterojunction SE is constructed by molten salt method for the zirconia-based impedancemetric NO_(2)sensor.The influence of the ZnWO_(4)/Li_(6)W_(2)O_(9)ratio on the performance of the sensor is investigated.The results show that Li_(6)W_(2)O_(9)in-situ formation on the surface of the ZnWO_(4)in LiNO_(3)molten at a low temperature of 300℃.The incorporation of Li_(6)W_(2)O_(9)enhances both the adsorption property and electrocatalytic activity of the SE,simultaneously,resulting in a significant increase in the sensitivity of sensor.The sensitivity increases gradually with the increasing incorporation of Li_(6)W_(2)O_(9).The sensitivity of ZnWO_(4)/37.5%Li_(6)W_(2)O_(9)sensor is significantly increased by 124%compared to the pristine ZnWO_(4)sensor and exhibits the largest sensitivity of 25.19(°)decade-1at 400℃.Moreover,the ZnWO_(4)/Li_(6)W_(2)O_(9)sensor also displays excellent selectivity,long-term stability,and repeatability.The introduction of in-situ formation by molten salt method is an effective strategy to develop gas sensors with large sensitivity.展开更多
With the rapid development of the internet of things(IoT)and wearable electronics,the role of flexible sensors is becoming increasingly irreplaceable,due to their ability to process and convert information acquisition...With the rapid development of the internet of things(IoT)and wearable electronics,the role of flexible sensors is becoming increasingly irreplaceable,due to their ability to process and convert information acquisition.Two-dimensional(2D)materials have been widely welcomed by researchers as sensitive layers,which broadens the range and application of flexible sensors due to the advantages of their large specific surface area,tunable energy bands,controllable thickness at the atomic level,stable mechanical properties,and excellent optoelectronic properties.This review focuses on five different types of 2D materials for monitoring pressure,humidity,sound,gas,and so on,to realize the recognition and conversion of human body and environmental signals.Meanwhile,the main problems and possible solutions of flexible sensors based on 2D materials as sensitive layers are summarized.展开更多
Acetone is a common volatile organic compound that can cause harm to human health when inhaled in small amounts.Therefore,the development of fast response and low detection limit acetone sensors becomes crucial.In thi...Acetone is a common volatile organic compound that can cause harm to human health when inhaled in small amounts.Therefore,the development of fast response and low detection limit acetone sensors becomes crucial.In this study,a core-shell spherical TiO_(2) sensor with a rich pore structure was designed.This sensor exhibited excellent sensing properties,including higher responsiveness(100 ppm acetone,R_(a)/R_(g)=80),lower detection limit(10 ppb)and short response time(8 s).The problem is that the sensing mechanism between TiO_(2) and acetone is not thoroughly analyzed.To gain further insight,the interaction process of TiO_(2) core-shell spheres and acetone under varying oxygen content environments was investigated by dynamic testing,X-ray photoelectron spectroscopy,in-situ Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry.The research results show that acetone not only adsorbs on the surface of the material and reacts with adsorbed oxygen,but also undergoes catalytic oxidation reaction with TiO_(2) core-shell spheres.Significantly,in high oxygen content environments,acetone undergoes oxidation to form intermediates such as acids and anhydrides that are difficult to desorpt on the surface of the material,thus prolonging the recovery time of the sensor.The discovery of this sensing process will provide some guidance for the design of acetone sensing materials in the future.Meanwhile,this also imparts valuable references and insights for the investigation of the mechanism and application of other sensitive metal oxide materials.展开更多
Wearable pressure sensors capable of adhering comfortably to the skin hold great promise in sound detection.However,current intelligent speech assistants based on pressure sensors can only recognize standard languages...Wearable pressure sensors capable of adhering comfortably to the skin hold great promise in sound detection.However,current intelligent speech assistants based on pressure sensors can only recognize standard languages,which hampers effective communication for non-standard language people.Here,we prepare an ultralight Ti_(3)C_(2)T_(x)MXene/chitosan/polyvinylidene difluoride composite aerogel with a detection range of 6.25 Pa-1200 k Pa,rapid response/recovery time,and low hysteresis(13.69%).The wearable aerogel pressure sensor can detect speech information through the throat muscle vibrations without any interference,allowing for accurate recognition of six dialects(96.2%accuracy)and seven different words(96.6%accuracy)with the assistance of convolutional neural networks.This work represents a significant step forward in silent speech recognition for human–machine interaction and physiological signal monitoring.展开更多
Listeria monocytogenes(LM)is a dangerous foodborne pathogen for humans.One emerging and validated method of indirectly assessing LM in food is detecting 3-hydroxy-2-butanone(3H2B)gas.In this study,the synthesis of 3-(...Listeria monocytogenes(LM)is a dangerous foodborne pathogen for humans.One emerging and validated method of indirectly assessing LM in food is detecting 3-hydroxy-2-butanone(3H2B)gas.In this study,the synthesis of 3-(2-aminoethylamino)propyltrimethoxysilane(AAPTMS)functionalized hierarchical hollow TiO_(2)nanospheres was achieved via precise controlling of solvothermal reaction temperature and post-grafting route.The sensors based on as-prepared materials exhibited excellent sensitivity(480 Hz@50 ppm),low detection limit(100 ppb),and outstanding selectivity.Moreover,the evaluation of LM with high sensitivity and specificity was achieved using the sensors.Such stable three-dimensional spheres,whose distinctive hierarchical and hollow nanostructure simultaneously improved both sensitivity and response/recovery speed dramatically,were spontaneously assembled by nanosheets.Meanwhile,the moderate loadings of AAPTMS significantly improved the selectivity of sensors.Then,the gas-sensing mechanism was explored by utilizing thermodynamic investigation,Gaussian 16 software,and in situ diffuse reflectance infrared transform spectroscopy,illustrating the weak chemisorption between the-NHgroup and 3H2B molecules.These portable sensors are promising for real-time assessment of LM at room temperature,which will make a magnificent contribution to food safety.展开更多
A high-performance ammonia(NH3)sensor is prepared based on CeO_(2)/NiO composite,using a hydrothermal method.Experimental findings confirm that the CeO_(2)/NiO composite significantly enhances the performance of the N...A high-performance ammonia(NH3)sensor is prepared based on CeO_(2)/NiO composite,using a hydrothermal method.Experimental findings confirm that the CeO_(2)/NiO composite significantly enhances the performance of the NiO-based NH3 sensor.This improvement is primarily due to the increase in oxygen vacancies(Ov),chemically adsorbed oxygen(Oc),and the proportion of Ni3+on the surface of the CeO_(2)/NiO.The CeO_(2)/NiO sensor shows a high response to NH3,exhibiting response/recovery times of 1.8 s/0.9 s at the NH3 concentration of 5×10^(−6)mL/m^(3),with the theoretical lowest detection limit of 98.651×10^(−9)mL/m^(3).Additionally,the CeO_(2)/NiO sensor has been successfully applied in the simulated detection of Helicobacter pylori infection,highlighting its significant research value and potential application prospects in biomedical diagnostics.展开更多
Quantitative determination of tetracycline(TC)in environment and foods is of great importance,as excessive residues might have negative effects on human health and environmental risks.Herein,a selfpowered molecularly ...Quantitative determination of tetracycline(TC)in environment and foods is of great importance,as excessive residues might have negative effects on human health and environmental risks.Herein,a selfpowered molecularly imprinted photoelectrochemical(PEC)sensor based on the Zn O/C photoanode and the Fe-doped CuBi_(2)O_(4)(CBFO)photocathode is developed for the sensitive detection of TC.The photocathodic current can be amplified by the efficient electron transfer caused by the Fermi energy level gap between the photoanode and photocathode.Furthermore,molecularly imprinted polymers(MIPs)at photocathode can selectivity identify the TC templates and thus improve the specificity.Under the optimal conditions,the sensor has a linear range of 10^(-2)-1.0×10^(5) nmol/L,and a limit of detection(LOD)of 0.007 nmol/L(S/N=3).More crucially,the milk sample detection is carried out using the as-prepared sensor,and the outcome is satisfactory.The research gives us a novel sensing platform for quick and accurate antibiotic(like TC)in environment and food monitoring.展开更多
Traditional Pt/C electrode materials are prone to corrosion and detachment during H_(2)S detection,leading to a decrease in fuel cell-type sensor performance.Here,a high-performance H_(2)S sensor based on Pt loaded Ti...Traditional Pt/C electrode materials are prone to corrosion and detachment during H_(2)S detection,leading to a decrease in fuel cell-type sensor performance.Here,a high-performance H_(2)S sensor based on Pt loaded Ti_(3)C_(2)electrode material with-O/-OH terminal groups was designed and prepared.Experimental tests showed that the Pt/Ti_(3)C_(2)sensor has good sensitivity(0.162μA/ppm)and a very low detection limit to H_(2)S(10 ppb).After 90 days of stability testing,the response of the Pt/Ti_(3)C_(2)sensor shows a smaller decrease of 2%compared to that of the Pt/C sensor(22.9%).Meanwhile,the sensor also has high selectivity and repeatability.The density functional theory(DFT)calculation combined with the experiment results revealed that the improved H_(2)S sensing mechanism is attributed to the fact that the strong interaction between Pt and Ti_(3)C_(2)via the Pt-O-Ti bonding can reduce the formation energy of Pt and Ti_(3)C_(2),ultimately prolonging the sensor’s service life.Furthermore,the catalytic property of Pt can decrease the adsorption energy and dissociation barrier of H_(2)S on Pt/Ti_(3)C_(2)surface,greatly enhance the ability to generate protons and effectively transfer charges,realizing good sensitivity and high selectivity of the sensor.The sensor works at room temperature,making it very promising in the field of H_(2)S detection in future.展开更多
The utilization of phosphors that achieve full-spectrum lighting has emerged as a prevailing trend in the advancement of white light-emitting diode(WLED)lighting.In this study,we successfully prepared a novel green ph...The utilization of phosphors that achieve full-spectrum lighting has emerged as a prevailing trend in the advancement of white light-emitting diode(WLED)lighting.In this study,we successfully prepared a novel green phosphor Ba_(2)Sc_(2)((BO_(3))_(2)B_(2)O_(5)):Ce^(3+)(BSBO:Ce^(3+))that can be utilized for full-spectrum lighting and low-temperature sensors.BSBO:Ce^(3+)exhibits a broad-band excitation spectrum centered at 410 nm,and a broad-band emission spectrum centered at 525 nm.The internal and external quantum efficiencies of BSBO:Ce^(3+)are 99%and 49%,respectively.The thermal stability of BSBO:Ce^(3+)can be improved by substituting partial Sc atoms with smaller cations.The thermal quenching mechanism of BSBO:Ce^(3+)and the lattice occupancy of Ce ions in BSBO are discussed in detail.Furthermore,by combining the green phosphor BSBO:Ce^(3+),the commercial blue phosphor and the red phosphor on a 405 nm chip,a white light source was obtained with a high average color rendering index(CRI)of 96.6,a low correlated color temperature(CCT)of 3988 K,and a high luminous efficacy of 88.0 Im/W.The lu-minous efficacy of the WLED exhibits negligible degradation during the 1000 h light aging experiment.What's more,an emission peak at 468 nm appears when excited at 352 nm and 80 K,however,the relative intensity of the peaks at 468 and 525 nm gradually weakens with increasing temperature,indicating the potential of this material as a low-temperature sensor.展开更多
The CO_2 sensing of PrFeO_3 and NdFeO_3 sensors were investigated. Experimental results show that the resistances for PrFeO_3 and NdFeO_3 in CO_2 gas are larger than those in air and the responses for PrFeO_3and NdFeO...The CO_2 sensing of PrFeO_3 and NdFeO_3 sensors were investigated. Experimental results show that the resistances for PrFeO_3 and NdFeO_3 in CO_2 gas are larger than those in air and the responses for PrFeO_3and NdFeO_3 sensors increase with an increase in room-temperature relative humidity. When exposed to1000 ppm CO_2, the response of PrFeO_3 thick film based on nano-powders annealed at 700℃can reach8.44 at 160℃for the background of wet air with 58%of room-temperature relative humidity (RH),which is much larger than the corresponding value (3.03) in wet air with 25%RH. The sensing response S of NdFeO_3 thick-film sensor based on nano-powders annealed at 600℃to 3000 ppm CO_2 at the operating temperature 200℃can reach 2.36 for the background of wet air with 72%RH, which is larger than the corresponding value (1.83) in the air with 25%RH. Compared with other CO_2 sensing materials, the PrFeO_3 sensor has larger response at lower operating temperature for CO_2 gas and may be used as a new CO_2 sensing material.展开更多
Flexible sensors based on MXene-polymer composites are highly prospective for next-generation wearable electronics used in human-machine interfaces.One of the motivating factors behind the progress of flexible sensors...Flexible sensors based on MXene-polymer composites are highly prospective for next-generation wearable electronics used in human-machine interfaces.One of the motivating factors behind the progress of flexible sensors is the steady arrival of new conductive materials.MXenes,a new family of 2D nanomaterials,have been draw-ing attention since the last decade due to their high electronic conduc-tivity,processability,mechanical robustness and chemical tunability.In this review,we encompass the fabrication of MXene-based polymeric nanocomposites,their structure-property relationship,and applications in the flexible sensor domain.Moreover,our discussion is not only lim-ited to sensor design,their mechanism,and various modes of sensing platform,but also their future perspective and market throughout the world.With our article,we intend to fortify the bond between flexible matrices and MXenes thus promoting the swift advancement of flexible MXene-sensors for wearable technologies.展开更多
Manganese ferrite(MnFe_(2)O_(4))has the advantages of simple preparation,high resistivity,and high crystal symmetry.Herein,we have developed an electrochemical sensor utilizing graphene and MnFe_(2)O_(4) nanocomposite...Manganese ferrite(MnFe_(2)O_(4))has the advantages of simple preparation,high resistivity,and high crystal symmetry.Herein,we have developed an electrochemical sensor utilizing graphene and MnFe_(2)O_(4) nanocomposites modified glassy carbon electrode(GCE),which is very efficient and sensitive to detect bisphenol A(BPA).MnFe_(2)O_(4)/graphene(GR)was synthesized by immobilizing the MnFe_(2)O_(4) microspheres on the graphene nanosheets via a simple one-pot solvothermal method.The morphology and structure of the MnFe_(2)O_(4)/GR nanocomposite have been characterized through scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FT-IR),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).In addition,electrochemical properties of the modified materials are comparably explored by means of cyclic voltammetry(CV),electrochemical impedance spectroscopy(EIS)and differential pulse voltammetry(DPV).Under the optimal conditions,the proposed electrochemical sensor for the detection of BPA has a linear range of 0.8-400μmol/L and a detection limit of 0.0235μmol/L(S/N=3)with high sensitivity,good selectivity and high stability.In addition,the proposed sensor was used to measure the content of BPA in real water samples with a recovery rate of 97.94%-104.56%.At present,the synthesis of MnFe_(2)O_(4)/GR provides more opportunities for the electrochemical detection of BPA in practical applications.展开更多
Owing to the ppb-level detection standard toward the toxic and harmful gas,the detection of trace gases has become an important subject in the field of indoor environment management.However,the traditional resistive g...Owing to the ppb-level detection standard toward the toxic and harmful gas,the detection of trace gases has become an important subject in the field of indoor environment management.However,the traditional resistive gas sensors hardly meet the requirement due to the weak signal generated by trace gas molecules that are difficult to capture.Herein,a visible-light-assisted Pd/TiO_(2)gas sensor is proposed to endow the effective detection of trace formaldehyde(HCHO)gas without heating temperature.Benefiting from the enhanced photocatalytic properties of TiO_(2)by Pd decoration,the visible-light-assisted Pd/TiO_(2)gas sensor can detect the HCHO gas as low as80×10^(–9)at room temperature.The successful preparation of nanoscale TiO_(2)sensing layer is facilitated by the ultrathin carbon nanotube interdigital electrode in the gas sensor,which avoids the discontinuity of the sensing layer caused by the excessive thickness of the traditional metal electrode.In addition,the whole preparation process of the Pd/TiO_(2)gas sensor with carbon nanotube electrodes is compatible with mainstream CMOS fabrication technology,which is expected to realize the batch fabrication and micro-integrated application of gas sensors.It is expected that our work can provide a new strategy for the batch preparation of high-performance trace HCHO gas sensors and their future applications in portable electronic devices such as smartphones.展开更多
A novel approach was developed to fabricate a label-free electrochemical aptasensor for specific detection of mercury ions(Hg^(2+)).This involved modifying polylysine(PLL)-coated black phosphorus-porous graphene(BP-PG...A novel approach was developed to fabricate a label-free electrochemical aptasensor for specific detection of mercury ions(Hg^(2+)).This involved modifying polylysine(PLL)-coated black phosphorus-porous graphene(BP-PG)nanocomposites(PLL/BP-PG)onto the surface of glassy carbon electrodes(GCE),which were further modified with gold nanoparticles(AuNPs)to combine with a thiolated aptamer(Apt)capable of specifically recognizing Hg^(2+).BP-PG was synthesized using the solvothermal method and covalently bonded to form BP-PG nanosheets,resulting in significant enhanced electrochemical properties of the PLL/BP-PG composite.Furthermore,the PLL/BP-PG composite was improved environmental stability of BP and provided a considerable quantity of-NH_(2)for bonding to Au NPs firmly by assembling.The physical properties and electrochemical behavior of the substrate materials were investigated using various characterization techniques,and analytical parameters were optimized.It is shown that,the Apt/AuNPs/PLL/BP-PG/GCE had a linear response(R~2=0.999)with good selectivity and high sensitivity over the Hg^(2+)range of 1-10,000 nmol/L.The proposed sensor has a detection limit of 0.045 nmol/L and can be employed for detecting of Hg^(2+).It also obtained satisfying results in river water,soil and vegetable samples.展开更多
Tube-type CO_2 gas sensors based on NASICON (Na Super Ion Conductor) material were fabricated.The material was synthesized by conventional sol-gel method,and the resulted powders were characterized by XRD.The tube-typ...Tube-type CO_2 gas sensors based on NASICON (Na Super Ion Conductor) material were fabricated.The material was synthesized by conventional sol-gel method,and the resulted powders were characterized by XRD.The tube-type CO_2 sensor was prepared with the sensing electrode Li_2CO_3-BaCO_3 binary carbonates in molar ratio 1:1.5.The concentration of CO_2 range from 300μg/g to 3000μg/g,the sensitivity of the sensor was 62.3 mV/decade.The response and recovery time (90%)corresponding to the switching change between 300μg/g and 1000μg/g CO_2 were 20 s and 2 min,respectively.If the sensing electrode was modified with binary oxides,the steady time of the sensor could be greatly reduced from 30 min to 5 min and the stability and humid-resistance of the sensor were improved.展开更多
Response speed is one of the most important evaluation criteria for CO2 sensors. In this work, we report an ultrafast CO2 fluorescent sensor based on poly[oligo（ethylene glycol） methyl ether methacrylate]-b-poly[N,N...Response speed is one of the most important evaluation criteria for CO2 sensors. In this work, we report an ultrafast CO2 fluorescent sensor based on poly[oligo（ethylene glycol） methyl ether methacrylate]-b-poly[N,N-diethylaminoethyl methacrylate-r-4-（2- methylacryloyloxyethylamino）-7-nitro-2,1,3-benzoxadiazole] [POEGMA-b-P（DEAEMA-r-NBDMA）], in which DEAEMA units act as the CO2-responsive segment and 4-nitrobenzo-2-oxa-l,3-diazole （NBD） is the chromophore. The micelles composed of this copolymer could disassemble in 2 s upon CO2 bubbling, accompanying with enhanced fluorescence emission with bathochromic shift. Furthermore, the quantum yield of the NBD chromophore increases with both the CO2 aeration time and the NBD content. Thus we attribute the fluorescent enhancement to the inhibition of the photo-induced electron transfer between unprotonated tertiary amine groups and NBD fluorophores. The sensor is durable although it is based on ＂soft＂ materials. These micellar sensors could be facilely recycled by alternative CO2/Ar purging for at least 5 times, indicating good reversibility.展开更多
基金supported by the Scientific Research Projects for State Environmental Protection and Commonweal (No. 200709048)the National Natural Science Foundation of China (No. 20977054/B070704)+1 种基金the Innovation Fund of Nankai UniversityJoint Research Grant to Both Nankai University and Tianjin University sponsored by the Ministry of Education,China
文摘A new air exchange rate （AER） monitoring method using continuous CO2 sensors was developed and validated through both laboratory experiments and field studies. Controlled laboratory simulation tests were conducted in a 1-m3 environmental chamber at different AERs （0.1-10.0 hr-1）. AERs were determined using the decay method based on box model assumptions. Field tests were conducted in classrooms, dormitories, meeting rooms and apartments during 2-5 weekdays using CO2 sensors coupled with data loggers. Indoor temperature, relative humidity （RH）, and CO2 concentrations were continuously monitored while outdoor parameters combined with on-site climate conditions were recorded. Statistical results indicated that good laboratory performance was achieved： duplicate precision was within 10%, and the measured AERs were 90%-120% of the real AERs. Average AERs were 1.22, 1.37, 1.10, 1.91 and 0.73 hr-l in dormitories, air-conditioned classrooms, classrooms with an air circulation cooling system, reading rooms, and meeting rooms, respectively. In an elderly particulate matter exposure study, all the homes had AER values ranging from 0.29 to 3.46 hr-1 in fall, and 0.12 to 1.39 hr-1 in winter with a median AER of 1.15.
文摘A type of CO2 sensor based on oxygen concentration cell was designed as following: Cell I: Pt | Au, O2, CO2| Na2CO3(Au)|NKBA(Au)|YSZ|O2, CO2|Pt or Cell lI: Pt|Au, O2, CO2|K2CO3(Au)|NKBA(Au)|YSZ|O2, CO2|Pt. (Na,K-β/β'-AI2O3 is named by NKBA). The sensor signal is consistent with the Nernstian slope within the region of phase equilibrium for Na, K-β/β'-AI2O3 material. The relationship between CO2 sensor voltage response and phase equilibrium of solid electrolyte Na, K-β/β-AI2O3 is discussed in this paper.
基金financially supported by the National Natural Science Foundation of China(No.52371187)the Innovation Capacity Enhancement Projects of Hebei Province(Nos.24461002D and 22567608H)+3 种基金the Natural Science Foundation of Hebei Province(Nos.E2024209044 and B2022209018)the Science and Technology Planning Project of Tangshan City(No.22130215G)Tangshan Talent Grant Program(No.A202202006)the Youth Scholars Promotion Plan of North China University of Science and Technology(No.QNTJ202206)
文摘The application of NO_(2)sensor reduces the emission of NO_(2)from the industry and automotive vehicles.However,insufficient electrocatalytic activity and adsorption to NO_(2)of sensing electrode(SE)limit the sensitivity increment of NO_(2)sensor.Thus,a novel ZnWO_(4)/Li_(6)W_(2)O_(9)heterojunction SE is constructed by molten salt method for the zirconia-based impedancemetric NO_(2)sensor.The influence of the ZnWO_(4)/Li_(6)W_(2)O_(9)ratio on the performance of the sensor is investigated.The results show that Li_(6)W_(2)O_(9)in-situ formation on the surface of the ZnWO_(4)in LiNO_(3)molten at a low temperature of 300℃.The incorporation of Li_(6)W_(2)O_(9)enhances both the adsorption property and electrocatalytic activity of the SE,simultaneously,resulting in a significant increase in the sensitivity of sensor.The sensitivity increases gradually with the increasing incorporation of Li_(6)W_(2)O_(9).The sensitivity of ZnWO_(4)/37.5%Li_(6)W_(2)O_(9)sensor is significantly increased by 124%compared to the pristine ZnWO_(4)sensor and exhibits the largest sensitivity of 25.19(°)decade-1at 400℃.Moreover,the ZnWO_(4)/Li_(6)W_(2)O_(9)sensor also displays excellent selectivity,long-term stability,and repeatability.The introduction of in-situ formation by molten salt method is an effective strategy to develop gas sensors with large sensitivity.
基金support of National Natural Science Foundation of China(Nos.52192610,62422120,52371202,52203307,52125205,52202181,and 52102184)Natural Science Foundation of Beijing(Nos.L223006 and 2222088).
文摘With the rapid development of the internet of things(IoT)and wearable electronics,the role of flexible sensors is becoming increasingly irreplaceable,due to their ability to process and convert information acquisition.Two-dimensional(2D)materials have been widely welcomed by researchers as sensitive layers,which broadens the range and application of flexible sensors due to the advantages of their large specific surface area,tunable energy bands,controllable thickness at the atomic level,stable mechanical properties,and excellent optoelectronic properties.This review focuses on five different types of 2D materials for monitoring pressure,humidity,sound,gas,and so on,to realize the recognition and conversion of human body and environmental signals.Meanwhile,the main problems and possible solutions of flexible sensors based on 2D materials as sensitive layers are summarized.
基金supported by the National Natural Science Foundation of China(Nos.21771060 and 61271126)the International Science&Technology Cooperation Program of China(No.2016YFE0115100)+2 种基金Heilongjiang Provincial Natural Science Foundation of China(No.LH_(2)023B021)Reform and Development Fund Project of Local University supported by the Central Government,Heilongjiang Touyan Innovation Team Program,New Era Excellent Master’s and Doctoral Dissertations of Heilongjiang Province(No.LJYXL2023-020)Basic Scientific Research Project for Heilongjiang Provincial Colleges and Universities(No.2023-KYYWF-1482).
文摘Acetone is a common volatile organic compound that can cause harm to human health when inhaled in small amounts.Therefore,the development of fast response and low detection limit acetone sensors becomes crucial.In this study,a core-shell spherical TiO_(2) sensor with a rich pore structure was designed.This sensor exhibited excellent sensing properties,including higher responsiveness(100 ppm acetone,R_(a)/R_(g)=80),lower detection limit(10 ppb)and short response time(8 s).The problem is that the sensing mechanism between TiO_(2) and acetone is not thoroughly analyzed.To gain further insight,the interaction process of TiO_(2) core-shell spheres and acetone under varying oxygen content environments was investigated by dynamic testing,X-ray photoelectron spectroscopy,in-situ Fourier transform infrared spectroscopy and gas chromatography-mass spectrometry.The research results show that acetone not only adsorbs on the surface of the material and reacts with adsorbed oxygen,but also undergoes catalytic oxidation reaction with TiO_(2) core-shell spheres.Significantly,in high oxygen content environments,acetone undergoes oxidation to form intermediates such as acids and anhydrides that are difficult to desorpt on the surface of the material,thus prolonging the recovery time of the sensor.The discovery of this sensing process will provide some guidance for the design of acetone sensing materials in the future.Meanwhile,this also imparts valuable references and insights for the investigation of the mechanism and application of other sensitive metal oxide materials.
基金supported by the National Nature Science Foundation of China(No.62122030,62333008,62371205,52103208)National Key Research and Development Program of China(No.2021YFB3201300)+1 种基金Application and Basic Research of Jilin Province(20130102010 JC)Fundamental Research Funds for the Central Universities,Jilin Provincial Science and Technology Development Program(20230101072JC)。
文摘Wearable pressure sensors capable of adhering comfortably to the skin hold great promise in sound detection.However,current intelligent speech assistants based on pressure sensors can only recognize standard languages,which hampers effective communication for non-standard language people.Here,we prepare an ultralight Ti_(3)C_(2)T_(x)MXene/chitosan/polyvinylidene difluoride composite aerogel with a detection range of 6.25 Pa-1200 k Pa,rapid response/recovery time,and low hysteresis(13.69%).The wearable aerogel pressure sensor can detect speech information through the throat muscle vibrations without any interference,allowing for accurate recognition of six dialects(96.2%accuracy)and seven different words(96.6%accuracy)with the assistance of convolutional neural networks.This work represents a significant step forward in silent speech recognition for human–machine interaction and physiological signal monitoring.
基金supported by the National Natural Science Foundation of China(No.32272399)the Shanghai Natural Science Foundation(No.21ZR1427500).
文摘Listeria monocytogenes(LM)is a dangerous foodborne pathogen for humans.One emerging and validated method of indirectly assessing LM in food is detecting 3-hydroxy-2-butanone(3H2B)gas.In this study,the synthesis of 3-(2-aminoethylamino)propyltrimethoxysilane(AAPTMS)functionalized hierarchical hollow TiO_(2)nanospheres was achieved via precise controlling of solvothermal reaction temperature and post-grafting route.The sensors based on as-prepared materials exhibited excellent sensitivity(480 Hz@50 ppm),low detection limit(100 ppb),and outstanding selectivity.Moreover,the evaluation of LM with high sensitivity and specificity was achieved using the sensors.Such stable three-dimensional spheres,whose distinctive hierarchical and hollow nanostructure simultaneously improved both sensitivity and response/recovery speed dramatically,were spontaneously assembled by nanosheets.Meanwhile,the moderate loadings of AAPTMS significantly improved the selectivity of sensors.Then,the gas-sensing mechanism was explored by utilizing thermodynamic investigation,Gaussian 16 software,and in situ diffuse reflectance infrared transform spectroscopy,illustrating the weak chemisorption between the-NHgroup and 3H2B molecules.These portable sensors are promising for real-time assessment of LM at room temperature,which will make a magnificent contribution to food safety.
基金supported by the Natural Science Foundation of Xinjiang Uygur Autonomous Region of China“Preparation and application of self-powered carbon nitride/metal oxide humidity sensors”(2023D01C05).
文摘A high-performance ammonia(NH3)sensor is prepared based on CeO_(2)/NiO composite,using a hydrothermal method.Experimental findings confirm that the CeO_(2)/NiO composite significantly enhances the performance of the NiO-based NH3 sensor.This improvement is primarily due to the increase in oxygen vacancies(Ov),chemically adsorbed oxygen(Oc),and the proportion of Ni3+on the surface of the CeO_(2)/NiO.The CeO_(2)/NiO sensor shows a high response to NH3,exhibiting response/recovery times of 1.8 s/0.9 s at the NH3 concentration of 5×10^(−6)mL/m^(3),with the theoretical lowest detection limit of 98.651×10^(−9)mL/m^(3).Additionally,the CeO_(2)/NiO sensor has been successfully applied in the simulated detection of Helicobacter pylori infection,highlighting its significant research value and potential application prospects in biomedical diagnostics.
基金supported by the Fuxiaquan Collaborative Innovation Platform(No.K30001)Major Scientific Research Program for Young and Middle-aged Health Professionals of Fujian Province,China(No.2022ZQNZD007)Youth Innovation Technology Project of Higher School in Shandong Province(Food Nanotechnology Innovation Team)。
文摘Quantitative determination of tetracycline(TC)in environment and foods is of great importance,as excessive residues might have negative effects on human health and environmental risks.Herein,a selfpowered molecularly imprinted photoelectrochemical(PEC)sensor based on the Zn O/C photoanode and the Fe-doped CuBi_(2)O_(4)(CBFO)photocathode is developed for the sensitive detection of TC.The photocathodic current can be amplified by the efficient electron transfer caused by the Fermi energy level gap between the photoanode and photocathode.Furthermore,molecularly imprinted polymers(MIPs)at photocathode can selectivity identify the TC templates and thus improve the specificity.Under the optimal conditions,the sensor has a linear range of 10^(-2)-1.0×10^(5) nmol/L,and a limit of detection(LOD)of 0.007 nmol/L(S/N=3).More crucially,the milk sample detection is carried out using the as-prepared sensor,and the outcome is satisfactory.The research gives us a novel sensing platform for quick and accurate antibiotic(like TC)in environment and food monitoring.
基金the National Key R&D Program of China(No.2023YFB3210102).
文摘Traditional Pt/C electrode materials are prone to corrosion and detachment during H_(2)S detection,leading to a decrease in fuel cell-type sensor performance.Here,a high-performance H_(2)S sensor based on Pt loaded Ti_(3)C_(2)electrode material with-O/-OH terminal groups was designed and prepared.Experimental tests showed that the Pt/Ti_(3)C_(2)sensor has good sensitivity(0.162μA/ppm)and a very low detection limit to H_(2)S(10 ppb).After 90 days of stability testing,the response of the Pt/Ti_(3)C_(2)sensor shows a smaller decrease of 2%compared to that of the Pt/C sensor(22.9%).Meanwhile,the sensor also has high selectivity and repeatability.The density functional theory(DFT)calculation combined with the experiment results revealed that the improved H_(2)S sensing mechanism is attributed to the fact that the strong interaction between Pt and Ti_(3)C_(2)via the Pt-O-Ti bonding can reduce the formation energy of Pt and Ti_(3)C_(2),ultimately prolonging the sensor’s service life.Furthermore,the catalytic property of Pt can decrease the adsorption energy and dissociation barrier of H_(2)S on Pt/Ti_(3)C_(2)surface,greatly enhance the ability to generate protons and effectively transfer charges,realizing good sensitivity and high selectivity of the sensor.The sensor works at room temperature,making it very promising in the field of H_(2)S detection in future.
基金the National Natural Science Foundation of China(22003035,21963006,22073061)the Project of Shaanxi Province Youth Science and Technology New Star(2023KJXX-076)the National Training Program of Innovation and Entrepreneurship for Undergraduates(202314390018)。
文摘The utilization of phosphors that achieve full-spectrum lighting has emerged as a prevailing trend in the advancement of white light-emitting diode(WLED)lighting.In this study,we successfully prepared a novel green phosphor Ba_(2)Sc_(2)((BO_(3))_(2)B_(2)O_(5)):Ce^(3+)(BSBO:Ce^(3+))that can be utilized for full-spectrum lighting and low-temperature sensors.BSBO:Ce^(3+)exhibits a broad-band excitation spectrum centered at 410 nm,and a broad-band emission spectrum centered at 525 nm.The internal and external quantum efficiencies of BSBO:Ce^(3+)are 99%and 49%,respectively.The thermal stability of BSBO:Ce^(3+)can be improved by substituting partial Sc atoms with smaller cations.The thermal quenching mechanism of BSBO:Ce^(3+)and the lattice occupancy of Ce ions in BSBO are discussed in detail.Furthermore,by combining the green phosphor BSBO:Ce^(3+),the commercial blue phosphor and the red phosphor on a 405 nm chip,a white light source was obtained with a high average color rendering index(CRI)of 96.6,a low correlated color temperature(CCT)of 3988 K,and a high luminous efficacy of 88.0 Im/W.The lu-minous efficacy of the WLED exhibits negligible degradation during the 1000 h light aging experiment.What's more,an emission peak at 468 nm appears when excited at 352 nm and 80 K,however,the relative intensity of the peaks at 468 and 525 nm gradually weakens with increasing temperature,indicating the potential of this material as a low-temperature sensor.
基金supported by National Natural Science Foundation of China(51272133,51472145,51772174 and 51472150)Shandong Natural Science Foundation(ZR2016EMM20)
文摘The CO_2 sensing of PrFeO_3 and NdFeO_3 sensors were investigated. Experimental results show that the resistances for PrFeO_3 and NdFeO_3 in CO_2 gas are larger than those in air and the responses for PrFeO_3and NdFeO_3 sensors increase with an increase in room-temperature relative humidity. When exposed to1000 ppm CO_2, the response of PrFeO_3 thick film based on nano-powders annealed at 700℃can reach8.44 at 160℃for the background of wet air with 58%of room-temperature relative humidity (RH),which is much larger than the corresponding value (3.03) in wet air with 25%RH. The sensing response S of NdFeO_3 thick-film sensor based on nano-powders annealed at 600℃to 3000 ppm CO_2 at the operating temperature 200℃can reach 2.36 for the background of wet air with 72%RH, which is larger than the corresponding value (1.83) in the air with 25%RH. Compared with other CO_2 sensing materials, the PrFeO_3 sensor has larger response at lower operating temperature for CO_2 gas and may be used as a new CO_2 sensing material.
基金The authors would like to acknowledge the support from the Natural Sciences and Engineering Research Council of Canada in the form of Discovery Grants to ARR and SS(RGPIN-2019-07246 and RGPIN-2022-04988).A.Rosenkranz greatly acknowledges the financial support given by ANID-Chile within the project Fondecyt Regular 1220331 and Fondequip EQM190057.B.Wang gratefully acknowledges the financial support given by the Alexander von Humboldt Foundation.
文摘Flexible sensors based on MXene-polymer composites are highly prospective for next-generation wearable electronics used in human-machine interfaces.One of the motivating factors behind the progress of flexible sensors is the steady arrival of new conductive materials.MXenes,a new family of 2D nanomaterials,have been draw-ing attention since the last decade due to their high electronic conduc-tivity,processability,mechanical robustness and chemical tunability.In this review,we encompass the fabrication of MXene-based polymeric nanocomposites,their structure-property relationship,and applications in the flexible sensor domain.Moreover,our discussion is not only lim-ited to sensor design,their mechanism,and various modes of sensing platform,but also their future perspective and market throughout the world.With our article,we intend to fortify the bond between flexible matrices and MXenes thus promoting the swift advancement of flexible MXene-sensors for wearable technologies.
基金Project(2108085ME184)supported by the Natural Science Foundation of Anhui Province,ChinaProject(2022AH010019)supported by the Innovation Team Project of Anhui Provincial Department of Education,China+1 种基金Project(GXXT-2021-057)supported by the Collaborative Innovation Project of Anhui Provincial Department of Education,ChinaProject(2020QDZ36)supported by the Doctoral Scientific Research Startup Foundation of Anhui Jianzhu University,China。
文摘Manganese ferrite(MnFe_(2)O_(4))has the advantages of simple preparation,high resistivity,and high crystal symmetry.Herein,we have developed an electrochemical sensor utilizing graphene and MnFe_(2)O_(4) nanocomposites modified glassy carbon electrode(GCE),which is very efficient and sensitive to detect bisphenol A(BPA).MnFe_(2)O_(4)/graphene(GR)was synthesized by immobilizing the MnFe_(2)O_(4) microspheres on the graphene nanosheets via a simple one-pot solvothermal method.The morphology and structure of the MnFe_(2)O_(4)/GR nanocomposite have been characterized through scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FT-IR),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).In addition,electrochemical properties of the modified materials are comparably explored by means of cyclic voltammetry(CV),electrochemical impedance spectroscopy(EIS)and differential pulse voltammetry(DPV).Under the optimal conditions,the proposed electrochemical sensor for the detection of BPA has a linear range of 0.8-400μmol/L and a detection limit of 0.0235μmol/L(S/N=3)with high sensitivity,good selectivity and high stability.In addition,the proposed sensor was used to measure the content of BPA in real water samples with a recovery rate of 97.94%-104.56%.At present,the synthesis of MnFe_(2)O_(4)/GR provides more opportunities for the electrochemical detection of BPA in practical applications.
基金financially supported by the National Natural Science Foundation of China(Nos.62071410 and 62101477)Hunan Provincial Natural Science Foundation(No.2021JJ40542)the Postgraduate Scientific Research Innovation Project of Hunan Province(No.CX20210627)。
文摘Owing to the ppb-level detection standard toward the toxic and harmful gas,the detection of trace gases has become an important subject in the field of indoor environment management.However,the traditional resistive gas sensors hardly meet the requirement due to the weak signal generated by trace gas molecules that are difficult to capture.Herein,a visible-light-assisted Pd/TiO_(2)gas sensor is proposed to endow the effective detection of trace formaldehyde(HCHO)gas without heating temperature.Benefiting from the enhanced photocatalytic properties of TiO_(2)by Pd decoration,the visible-light-assisted Pd/TiO_(2)gas sensor can detect the HCHO gas as low as80×10^(–9)at room temperature.The successful preparation of nanoscale TiO_(2)sensing layer is facilitated by the ultrathin carbon nanotube interdigital electrode in the gas sensor,which avoids the discontinuity of the sensing layer caused by the excessive thickness of the traditional metal electrode.In addition,the whole preparation process of the Pd/TiO_(2)gas sensor with carbon nanotube electrodes is compatible with mainstream CMOS fabrication technology,which is expected to realize the batch fabrication and micro-integrated application of gas sensors.It is expected that our work can provide a new strategy for the batch preparation of high-performance trace HCHO gas sensors and their future applications in portable electronic devices such as smartphones.
基金financially supported by the NSF of China(No.61871180)2022 Special Project for the Construction of Innovative Provinces to Fight the COVID-19 Outbreak(No.2022SK2115)+1 种基金Natural Science Foundation of Hunan Province of China(Nos.2022JJ30230,2021JJ30213)the Deanship of Scientific Research,Taif University。
文摘A novel approach was developed to fabricate a label-free electrochemical aptasensor for specific detection of mercury ions(Hg^(2+)).This involved modifying polylysine(PLL)-coated black phosphorus-porous graphene(BP-PG)nanocomposites(PLL/BP-PG)onto the surface of glassy carbon electrodes(GCE),which were further modified with gold nanoparticles(AuNPs)to combine with a thiolated aptamer(Apt)capable of specifically recognizing Hg^(2+).BP-PG was synthesized using the solvothermal method and covalently bonded to form BP-PG nanosheets,resulting in significant enhanced electrochemical properties of the PLL/BP-PG composite.Furthermore,the PLL/BP-PG composite was improved environmental stability of BP and provided a considerable quantity of-NH_(2)for bonding to Au NPs firmly by assembling.The physical properties and electrochemical behavior of the substrate materials were investigated using various characterization techniques,and analytical parameters were optimized.It is shown that,the Apt/AuNPs/PLL/BP-PG/GCE had a linear response(R~2=0.999)with good selectivity and high sensitivity over the Hg^(2+)range of 1-10,000 nmol/L.The proposed sensor has a detection limit of 0.045 nmol/L and can be employed for detecting of Hg^(2+).It also obtained satisfying results in river water,soil and vegetable samples.
基金The authors acknowledge Natural Science Foundation of China （No.60174033）；ministry of education and Innovation Foundation of Jilin University
文摘Tube-type CO_2 gas sensors based on NASICON (Na Super Ion Conductor) material were fabricated.The material was synthesized by conventional sol-gel method,and the resulted powders were characterized by XRD.The tube-type CO_2 sensor was prepared with the sensing electrode Li_2CO_3-BaCO_3 binary carbonates in molar ratio 1:1.5.The concentration of CO_2 range from 300μg/g to 3000μg/g,the sensitivity of the sensor was 62.3 mV/decade.The response and recovery time (90%)corresponding to the switching change between 300μg/g and 1000μg/g CO_2 were 20 s and 2 min,respectively.If the sensing electrode was modified with binary oxides,the steady time of the sensor could be greatly reduced from 30 min to 5 min and the stability and humid-resistance of the sensor were improved.
基金financially supported by the National Natural Science Foundation of China (Nos. 51573086 and 21374058)the Opening Project of State Key Laboratory of Polymer Materials Engineering (Sichuan University) (No. sklpme2014-4-26)
文摘Response speed is one of the most important evaluation criteria for CO2 sensors. In this work, we report an ultrafast CO2 fluorescent sensor based on poly[oligo（ethylene glycol） methyl ether methacrylate]-b-poly[N,N-diethylaminoethyl methacrylate-r-4-（2- methylacryloyloxyethylamino）-7-nitro-2,1,3-benzoxadiazole] [POEGMA-b-P（DEAEMA-r-NBDMA）], in which DEAEMA units act as the CO2-responsive segment and 4-nitrobenzo-2-oxa-l,3-diazole （NBD） is the chromophore. The micelles composed of this copolymer could disassemble in 2 s upon CO2 bubbling, accompanying with enhanced fluorescence emission with bathochromic shift. Furthermore, the quantum yield of the NBD chromophore increases with both the CO2 aeration time and the NBD content. Thus we attribute the fluorescent enhancement to the inhibition of the photo-induced electron transfer between unprotonated tertiary amine groups and NBD fluorophores. The sensor is durable although it is based on ＂soft＂ materials. These micellar sensors could be facilely recycled by alternative CO2/Ar purging for at least 5 times, indicating good reversibility.
