ZnO nanocrystals were prepared by a direct current electrochemical deposition process under 3.0V working voltage and 30A/m^2 current density using zinc sulfate as raw materials.The nanocrystals were characterized by X...ZnO nanocrystals were prepared by a direct current electrochemical deposition process under 3.0V working voltage and 30A/m^2 current density using zinc sulfate as raw materials.The nanocrystals were characterized by X-ray diffraction (XRD)and transmission electron microscopy(TEM).The results indicated that the nanocrystals are hexagonal wurtzite ZnO with particle size range of 25nm～40nm without any treating.Gas sensing properties of the sensors were tested by mixing a gas in air at static state;the tested results showed that the sensors based on nanocrystalline ZnO had satisfied gas sensing properties to H_2S gas at rather low temperature.展开更多
The sensitivity and selectivity to H_2 of a new In_2O_3-based gas sensor were improvedsignificantly by surface chemical modification. A dense layer of SiO_2 near the surface of the porousIn_2O_3 bead was formed by che...The sensitivity and selectivity to H_2 of a new In_2O_3-based gas sensor were improvedsignificantly by surface chemical modification. A dense layer of SiO_2 near the surface of the porousIn_2O_3 bead was formed by chemical vapor deposition(CVD)of diethoxydimethysilane(DEMS).The dense layer functioned as a molecular sieve, thereby the diffusion of gases with large moleculardiameters,except for H_2, was effectively controlled, resulting in a prominent selectivity and highsensitivity for H_2. The working mechanism of the sensor was also presented.展开更多
<正>SnO_2 thin film sensors were fabricated by a thermal evaporation method.The sensors were heated for thermal oxidation.For high porosity,SnO_2 thin film sensors were treated in a N_2 atmosphere.The sensors th...<正>SnO_2 thin film sensors were fabricated by a thermal evaporation method.The sensors were heated for thermal oxidation.For high porosity,SnO_2 thin film sensors were treated in a N_2 atmosphere.The sensors that were treated with O_2 after being treated with N_2 showed 70 % sensitivity for 1×10~ -6) of H_2S,which is higher than the sensors that were only treated with O_2.The Ni metal,as a catalyst,was evaporated on the thin film Sn on the Al_2O_3 substrate.The sensor was heated to grow the Sn nanowire in a tube furnace with N_2 flow.Sn nanowire was heated for oxidation.The sensitivity of SnO_2 nanowire sensor was measured for 500×10~ -9) of H_2S.The selectivity of the SnO_2 nanowire sensor was compared with the thin film and the thick film SnO_2.Each sensor was measured for H_2S,CO,and NH_3 in this study.展开更多
Nanostructured tin dioxide （SnO2） powders were prepared by a sol-gel dialytic process and and the doping of CuO on it was completed by a deposition-precipitation method.The thick film sensors were fabricated from th...Nanostructured tin dioxide （SnO2） powders were prepared by a sol-gel dialytic process and and the doping of CuO on it was completed by a deposition-precipitation method.The thick film sensors were fabricated from the CuO/SnO2 polycrystalline powders.Sensing behavior of the sensor was investigated with various gases including CO,H2,NH3,hexane,acetone,ethanol,methanol and H2S in air.The as-synthesized gas sensor had much better response to H2S than to other gases.At the same time,the CuO/SnO2 sensor had enough sensitivity,together with fast response and recovery,to distinguish H2S from those gases at 160 and 210 ℃.Therefore,it might have promising applications in the future.展开更多
The ZnO nanostructures have been synthesized and studied as the sensing element for the detection of H2S. The ZnO nanostructures were synthesized by hydrothermal method followed by sonication for different interval of...The ZnO nanostructures have been synthesized and studied as the sensing element for the detection of H2S. The ZnO nanostructures were synthesized by hydrothermal method followed by sonication for different interval of time i.e. 30, 60, 90 and 120 min. By using screen printing method, thick films of synthesized ZnO nanostructure were deposited on glass substrate. Gas sensing properties of ZnO nanostructure thick films were studied for low concentration H2S gas at room temperature. The effects of morphology of synthesized ZnO nanostructure on gas sensing properties were studied and discussed. ZnO nanostructure synthesized by this method can be used as a promising material for semiconductor gas sensor to detect poisonous gas like H2S at room temperature with high sensitivity and selectivity.展开更多
The zinc oxide(ZnO)nanoparticles(NPs)sensors were prepared in-situ on the gas-sensing electrodes by a one-step simple sol-gel method for the detection of hydrogen sulfide(H_(2)S)gas.The sphere-like ZnO NPs were charac...The zinc oxide(ZnO)nanoparticles(NPs)sensors were prepared in-situ on the gas-sensing electrodes by a one-step simple sol-gel method for the detection of hydrogen sulfide(H_(2)S)gas.The sphere-like ZnO NPs were characterized by scanning electron microscopy(SEM),transmission electron microscopy(TEM),x-ray diffraction(XRD),energy dispersive x-ray analysis(EDX),and their H_(2)S sensing performance were measured at room temperature.Testing results indicate that the ZnO NPs exhibit excellent response to H_(2)S gas at room temperature.The response value of the optimal sample to750 ppb H_(2)S is 73.3%,the detection limit reaches to 30 ppb,and the response value is 7.5%.Furthermore,the effects of the calcining time and thickness of the film on the gas-sensing performance were investigated.Both calcining time and film thickness show a negative correlation with the H_(2)S sensing performance.The corresponding reaction mechanism of H_(2)S detection was also discussed.展开更多
Geological storage of acid gas has been identified as a promising approach to reduce atmospheric carbon dioxide(CO_(2)),hydrogen sulfide(H_(2)S)and alleviate public concern resulting from the sour gas production.A goo...Geological storage of acid gas has been identified as a promising approach to reduce atmospheric carbon dioxide(CO_(2)),hydrogen sulfide(H_(2)S)and alleviate public concern resulting from the sour gas production.A good understanding of the relative permeability and capillary pressure characteristics is crucial to predict the process of acid gas injection and migration.The prediction of injection and redistribution of acid gas is important to determine storage capacity,formation pressure,plume extent,shape,and leakage potential.Herein,the existing experimental data and theoretical models were reviewed to gain a better understanding of the issue how the H_(2)S content affects gas density,gas viscosity,interfacial tension,wettability,relative permeability and capillary pressure characteristics of acid gas/brine/rock systems.The densities and viscosities of the acid gas with different H_(2)S mole fractions are both temperature-and pressure-dependent,which vary among the gas,liquid and supercritical phases.Water/acid gas interfacial tension decreases strongly with increasing H_(2)S content.For mica and clean quartz,water contact angle increases with increasing H_(2)S mole fraction.In particular,wettability reversal of mica to a H_(2)S-wet behavior occurs in the presence of dense H_(2)S.The capillary pressure increases with decreasing contact angle.At a given saturation,the relative permeability of a fluid is higher when the fluid is nonwetting.The capillary pressure decreases with decreasing interfacial tension at a given saturation.However,the existing datasets do not show a consistent link between capillary number and relative permeability.The capillary pressure decreases with increasing H_(2)S mole fraction.However,there is no consensus on the effect of the H_(2)S content on the relative permeability curves.This may be due to the limited availability of the relative permeability and capillary pressure data for acid gas/brine/rock systems;thus,more experimental measurements are required.展开更多
Owing to their higher intrinsic electrical conductivity and chemical stability with respect to their oxide counterparts, nanostructured metal sulfides are expected to revive materials for resistive chemical sensor app...Owing to their higher intrinsic electrical conductivity and chemical stability with respect to their oxide counterparts, nanostructured metal sulfides are expected to revive materials for resistive chemical sensor applications. Herein, we explore the gas sensing behavior of WS2 nanowire-nanoflake hybrid materials and demonstrate their excellent sensitivity （0.043 ppm-1） as well as high selectivity towards H2S relative to CO, NH~, H2, and NO （with corresponding sensitivities of 0.002, 0.0074, 0.0002, and 0.0046 pprn-1, respectively）. Gas response measurements, complemented with the results of X-ray photoelectron spectroscopy analysis and first-principles calculations based on density functional theory, suggest that the intrinsic electronic properties of pristine WS2 alone are not sufficient to explain the observed high sensitivity towards H2S. A major role in this behavior is also played by O doping in the S sites of the WS2 lattice. The results of the present study open up new avenues for the use of transition metal disulfide nanomaterials as effective alternatives to metal oxides in future applications for industrial process control, security, and health and environmental safety.展开更多
Nanocomposites composed of SnO2 and CuO were prepared by hydrothermal method. The microstructures of obtained SnO2-CuO powders were characterized by X-ray diffraction, scanning electron microscopy, transmission electr...Nanocomposites composed of SnO2 and CuO were prepared by hydrothermal method. The microstructures of obtained SnO2-CuO powders were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption test. The results show that the nanocomposites exhibited coral-like nanostructure, and the average crystalline size of SnO2 was 12 nm. The specific surface area of the four samples, SnO2- 0.2CuO, SnO2-0.5CuO, SnO2-1.0CuO and SnO2-2.0CuO are 72.97, 58.77, 49.72 and 54.95 m2/g, respectively. The gas sensing performance of the four samples to ethanol, formaldehyde and H2S was studied. The sensor of SnOa-0.5CuO exhibited high response to hydrogen sulfide （4173 to 10 ppm H2S, where ppm represent 10-6）, and low response to ethanol and formaldehyde. The good selectivity exhibited that the SnO2-0.5CuO nanocomposite can be a promising candidate for highly sensitive and selective gas-sensing material to H2S.展开更多
Detection of trace-level hydrogen sulfide(H2 S)gas is of great importance whether in industrial production or disease diagnosis.This research presents a novel H2 S gas sensor based on integrated resonant dual-microcan...Detection of trace-level hydrogen sulfide(H2 S)gas is of great importance whether in industrial production or disease diagnosis.This research presents a novel H2 S gas sensor based on integrated resonant dual-microcantilevers which can identify and detect trace-level H2 S in real-time.The sensor consists of two integrated resonant microcantilever sensors with different functions.One cantilever sensor can identify H2 S by outputting positive frequency shift signals,while the other cantilever sensor will detect H2 S as a normally used cantilever sensor with negative frequency shifts.Combined the two cantilever sensors,the proposed gas sensor can distinguish H2 S from a variety of common gases,and the detection limit to H2 S of the sensor is as sensitive as below 1 ppb.展开更多
H_(2)S selective catalytic oxidation technology is a prospective way for the treatment of low concentration acid gas with simple process operation and low investment. However, undesirable results such as large formati...H_(2)S selective catalytic oxidation technology is a prospective way for the treatment of low concentration acid gas with simple process operation and low investment. However, undesirable results such as large formation of SO_(2) and catalyst deactivation inevitably occur, due to the temperature rise of fixed reaction bed caused by the exothermic reaction. Catalyst with high activity in wide operating temperature window, especially in high temperature range, is urgently needed. In this paper, a series of copper-substituted hexaaluminate catalysts (LaCu_(x), x = 0, 0.5, 1, 1.5, 2, 2.5) were prepared and investigated for the H_(2)S selective oxidation reaction at high temperature conditions (300-550℃). The LaCu_(1) catalyst exhibited excellent catalytic performance and great stability, which was attributed to the best reductive properties and proper pore structure. Besides, two facile deep processing paths were proposed to eliminate the remaining H_(2)S and SO_(2) in the tail gas.展开更多
文摘ZnO nanocrystals were prepared by a direct current electrochemical deposition process under 3.0V working voltage and 30A/m^2 current density using zinc sulfate as raw materials.The nanocrystals were characterized by X-ray diffraction (XRD)and transmission electron microscopy(TEM).The results indicated that the nanocrystals are hexagonal wurtzite ZnO with particle size range of 25nm～40nm without any treating.Gas sensing properties of the sensors were tested by mixing a gas in air at static state;the tested results showed that the sensors based on nanocrystalline ZnO had satisfied gas sensing properties to H_2S gas at rather low temperature.
文摘The sensitivity and selectivity to H_2 of a new In_2O_3-based gas sensor were improvedsignificantly by surface chemical modification. A dense layer of SiO_2 near the surface of the porousIn_2O_3 bead was formed by chemical vapor deposition(CVD)of diethoxydimethysilane(DEMS).The dense layer functioned as a molecular sieve, thereby the diffusion of gases with large moleculardiameters,except for H_2, was effectively controlled, resulting in a prominent selectivity and highsensitivity for H_2. The working mechanism of the sensor was also presented.
文摘<正>SnO_2 thin film sensors were fabricated by a thermal evaporation method.The sensors were heated for thermal oxidation.For high porosity,SnO_2 thin film sensors were treated in a N_2 atmosphere.The sensors that were treated with O_2 after being treated with N_2 showed 70 % sensitivity for 1×10~ -6) of H_2S,which is higher than the sensors that were only treated with O_2.The Ni metal,as a catalyst,was evaporated on the thin film Sn on the Al_2O_3 substrate.The sensor was heated to grow the Sn nanowire in a tube furnace with N_2 flow.Sn nanowire was heated for oxidation.The sensitivity of SnO_2 nanowire sensor was measured for 500×10~ -9) of H_2S.The selectivity of the SnO_2 nanowire sensor was compared with the thin film and the thick film SnO_2.Each sensor was measured for H_2S,CO,and NH_3 in this study.
文摘Nanostructured tin dioxide （SnO2） powders were prepared by a sol-gel dialytic process and and the doping of CuO on it was completed by a deposition-precipitation method.The thick film sensors were fabricated from the CuO/SnO2 polycrystalline powders.Sensing behavior of the sensor was investigated with various gases including CO,H2,NH3,hexane,acetone,ethanol,methanol and H2S in air.The as-synthesized gas sensor had much better response to H2S than to other gases.At the same time,the CuO/SnO2 sensor had enough sensitivity,together with fast response and recovery,to distinguish H2S from those gases at 160 and 210 ℃.Therefore,it might have promising applications in the future.
文摘The ZnO nanostructures have been synthesized and studied as the sensing element for the detection of H2S. The ZnO nanostructures were synthesized by hydrothermal method followed by sonication for different interval of time i.e. 30, 60, 90 and 120 min. By using screen printing method, thick films of synthesized ZnO nanostructure were deposited on glass substrate. Gas sensing properties of ZnO nanostructure thick films were studied for low concentration H2S gas at room temperature. The effects of morphology of synthesized ZnO nanostructure on gas sensing properties were studied and discussed. ZnO nanostructure synthesized by this method can be used as a promising material for semiconductor gas sensor to detect poisonous gas like H2S at room temperature with high sensitivity and selectivity.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11904209 and 61904098)the Natural Science Foundation of Shandong Province,China(Grant No.ZR2019QF018)Higher Education Research and Development Program of Shandong Province,China(Grant No.J18KA242)。
文摘The zinc oxide(ZnO)nanoparticles(NPs)sensors were prepared in-situ on the gas-sensing electrodes by a one-step simple sol-gel method for the detection of hydrogen sulfide(H_(2)S)gas.The sphere-like ZnO NPs were characterized by scanning electron microscopy(SEM),transmission electron microscopy(TEM),x-ray diffraction(XRD),energy dispersive x-ray analysis(EDX),and their H_(2)S sensing performance were measured at room temperature.Testing results indicate that the ZnO NPs exhibit excellent response to H_(2)S gas at room temperature.The response value of the optimal sample to750 ppb H_(2)S is 73.3%,the detection limit reaches to 30 ppb,and the response value is 7.5%.Furthermore,the effects of the calcining time and thickness of the film on the gas-sensing performance were investigated.Both calcining time and film thickness show a negative correlation with the H_(2)S sensing performance.The corresponding reaction mechanism of H_(2)S detection was also discussed.
基金the National Natural Science Foundation of China(Grant Nos.41872210 and 41274111)the Open Research Fund of State Key Laboratory of Geomechanics and Geotechnical Engineering(Grant No.Z018002)。
文摘Geological storage of acid gas has been identified as a promising approach to reduce atmospheric carbon dioxide(CO_(2)),hydrogen sulfide(H_(2)S)and alleviate public concern resulting from the sour gas production.A good understanding of the relative permeability and capillary pressure characteristics is crucial to predict the process of acid gas injection and migration.The prediction of injection and redistribution of acid gas is important to determine storage capacity,formation pressure,plume extent,shape,and leakage potential.Herein,the existing experimental data and theoretical models were reviewed to gain a better understanding of the issue how the H_(2)S content affects gas density,gas viscosity,interfacial tension,wettability,relative permeability and capillary pressure characteristics of acid gas/brine/rock systems.The densities and viscosities of the acid gas with different H_(2)S mole fractions are both temperature-and pressure-dependent,which vary among the gas,liquid and supercritical phases.Water/acid gas interfacial tension decreases strongly with increasing H_(2)S content.For mica and clean quartz,water contact angle increases with increasing H_(2)S mole fraction.In particular,wettability reversal of mica to a H_(2)S-wet behavior occurs in the presence of dense H_(2)S.The capillary pressure increases with decreasing contact angle.At a given saturation,the relative permeability of a fluid is higher when the fluid is nonwetting.The capillary pressure decreases with decreasing interfacial tension at a given saturation.However,the existing datasets do not show a consistent link between capillary number and relative permeability.The capillary pressure decreases with increasing H_(2)S mole fraction.However,there is no consensus on the effect of the H_(2)S content on the relative permeability curves.This may be due to the limited availability of the relative permeability and capillary pressure data for acid gas/brine/rock systems;thus,more experimental measurements are required.
文摘Owing to their higher intrinsic electrical conductivity and chemical stability with respect to their oxide counterparts, nanostructured metal sulfides are expected to revive materials for resistive chemical sensor applications. Herein, we explore the gas sensing behavior of WS2 nanowire-nanoflake hybrid materials and demonstrate their excellent sensitivity （0.043 ppm-1） as well as high selectivity towards H2S relative to CO, NH~, H2, and NO （with corresponding sensitivities of 0.002, 0.0074, 0.0002, and 0.0046 pprn-1, respectively）. Gas response measurements, complemented with the results of X-ray photoelectron spectroscopy analysis and first-principles calculations based on density functional theory, suggest that the intrinsic electronic properties of pristine WS2 alone are not sufficient to explain the observed high sensitivity towards H2S. A major role in this behavior is also played by O doping in the S sites of the WS2 lattice. The results of the present study open up new avenues for the use of transition metal disulfide nanomaterials as effective alternatives to metal oxides in future applications for industrial process control, security, and health and environmental safety.
基金financially supported by the National Natural Science Foundation of China (No. 51072141)the scientific research projects of Education Department of Hubei province (D20141503)the President Foundation of Wuhan Institute of Technology (No. 2014029)
文摘Nanocomposites composed of SnO2 and CuO were prepared by hydrothermal method. The microstructures of obtained SnO2-CuO powders were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption test. The results show that the nanocomposites exhibited coral-like nanostructure, and the average crystalline size of SnO2 was 12 nm. The specific surface area of the four samples, SnO2- 0.2CuO, SnO2-0.5CuO, SnO2-1.0CuO and SnO2-2.0CuO are 72.97, 58.77, 49.72 and 54.95 m2/g, respectively. The gas sensing performance of the four samples to ethanol, formaldehyde and H2S was studied. The sensor of SnOa-0.5CuO exhibited high response to hydrogen sulfide （4173 to 10 ppm H2S, where ppm represent 10-6）, and low response to ethanol and formaldehyde. The good selectivity exhibited that the SnO2-0.5CuO nanocomposite can be a promising candidate for highly sensitive and selective gas-sensing material to H2S.
基金supported by National Key R&D Program of China(No.2016YFA0200800)National Natural Science Foundation of China(NSFC,Nos.61874130,61604163,61527818,61604162)+1 种基金Key Research Program of Frontier Sciences of Chinese Academy of Sciences(No.QYZDJ-SSW-JSC001)the financial support of the Youth Innovation Promotion Association CAS(No.2017278)。
文摘Detection of trace-level hydrogen sulfide(H2 S)gas is of great importance whether in industrial production or disease diagnosis.This research presents a novel H2 S gas sensor based on integrated resonant dual-microcantilevers which can identify and detect trace-level H2 S in real-time.The sensor consists of two integrated resonant microcantilever sensors with different functions.One cantilever sensor can identify H2 S by outputting positive frequency shift signals,while the other cantilever sensor will detect H2 S as a normally used cantilever sensor with negative frequency shifts.Combined the two cantilever sensors,the proposed gas sensor can distinguish H2 S from a variety of common gases,and the detection limit to H2 S of the sensor is as sensitive as below 1 ppb.
基金financially supported by the National Natural Science Foundation of China (Nos. 21976176, 22006148)the Key R&D Program of Shandong province (No. 2019JZZY010506)the Fundamental Research Funds for the Central Universities。
文摘H_(2)S selective catalytic oxidation technology is a prospective way for the treatment of low concentration acid gas with simple process operation and low investment. However, undesirable results such as large formation of SO_(2) and catalyst deactivation inevitably occur, due to the temperature rise of fixed reaction bed caused by the exothermic reaction. Catalyst with high activity in wide operating temperature window, especially in high temperature range, is urgently needed. In this paper, a series of copper-substituted hexaaluminate catalysts (LaCu_(x), x = 0, 0.5, 1, 1.5, 2, 2.5) were prepared and investigated for the H_(2)S selective oxidation reaction at high temperature conditions (300-550℃). The LaCu_(1) catalyst exhibited excellent catalytic performance and great stability, which was attributed to the best reductive properties and proper pore structure. Besides, two facile deep processing paths were proposed to eliminate the remaining H_(2)S and SO_(2) in the tail gas.
