The conversion of carbon dioxide into valuable organic compounds is a highly promising approach to address the energy issues and environmental problems(e.g., global warming). Herein, we presents a facile and efficient...The conversion of carbon dioxide into valuable organic compounds is a highly promising approach to address the energy issues and environmental problems(e.g., global warming). Herein, we presents a facile and efficient method to prepare highly dense and well-dispersed SnO2 nanocrystals on 1 D N-doped carbon nanowires as advanced catalysts for the efficient electroreduction of CO2 to formate. The ultrasmall SnO2 coated on the N-doped carbon nanowires(SnO2@N-CNW) has been synthesized via the simple hydrothermal treatment coupled with a pyrolysis process. The unique structure enables to expose the active tin oxide and also provides the facile pathways for rapid transfer of electron and electrolyte along with the highly porous carbon foam composed with interconnected carbon nanowires. Therefore, SnO2@NCNW electrocatalyst exhibits good durability and high selectivity for formate formation with a Faradaic efficiency of ca. 90%. This work demonstrates a simple method to rationally design high-dense tin oxide nanocrystals on the conductive carbon support as advanced catalysts for CO2 electroreduction.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
It is well-known that the electrolytes can influence the electrochemical reduction of carbon dioxide(ERCO2)in aqueous media.In this work,we explore the effects of alkali metal cations and anions(Li^+,Na^+,K^+,Rb^+,Cs^...It is well-known that the electrolytes can influence the electrochemical reduction of carbon dioxide(ERCO2)in aqueous media.In this work,we explore the effects of alkali metal cations and anions(Li^+,Na^+,K^+,Rb^+,Cs^+,HCO3^-,Cl^-,Br^-,I^-)on the current density and product selectivity for the ERCO2 into formic acid(HCOOH)on the SnO2/carbon paper(Sn O2/C)electrode.Results of the ERCO2 experiments show that for the cations,the promotion effects on current density and faradaic efficiencies(FEs)are in the order of Li^+b Na^+b K^+b Cs^+b Rb^+.For the anions,the current density values are in the order of Na HCO3 b NaClb Na Br b Na I and KHCO3 b KCl≈KI b KBr,respectively,and that on the FEs for the formation of the HCOOH(FEHCOOH)is HCO3-b Cl-b Br-b I-.Based on this result,the effects of alkali metal cations and anions on ERCO2 are discussed.展开更多
The steam regeneration and SO2 regeneration of tin oxide for warm syngas desulfurization is studied in the temperature range of 400-600 ℃. In the steam regeneration, reversible removal of H2S achieved. Regenerated H2...The steam regeneration and SO2 regeneration of tin oxide for warm syngas desulfurization is studied in the temperature range of 400-600 ℃. In the steam regeneration, reversible removal of H2S achieved. Regenerated H2S concentration increased with the increasing regeneration temperature. SnO2 sorbent can achieve a complete regeneration by steam at 500 and 600 ℃. In the 502 regeneration, elemental sulfur was produced by the reaction of SnS and SO2. Raising the regeneration temperature （500-600 ℃） or SO2 concentration （1.5-10 vol%） improved the regeneration rate. Under SO2 regeneration at 500 ℃, SnS2 formed in the sorbent due to the interconversion of tin sulfides. Under steam regeneration or SO2 regeneration, the cyclic breakthrough sulfur capacity of SnO2 sorbent decreased because of the sintering caused by low melting component SnS. A two-stage regeneration process was applied to recover the elemental sulfur which achieved a complete regeneration.展开更多
Indium tin oxide(ITO)nanopowders were prepared by a modified chemical co-precipitation process.The influence of different SnO2 contents on the decomposition behavior of ITO precursors,and on the phase and morphology o...Indium tin oxide(ITO)nanopowders were prepared by a modified chemical co-precipitation process.The influence of different SnO2 contents on the decomposition behavior of ITO precursors,and on the phase and morphology of ITO precursors and ITO nanopowders were studied by X-ray diffractometry,transmission electron microscopy and differential thermal and thermogravimetry analysis methods.The TG-DSC curves show that the decomposition process of precursor precipitation is completed when the temperature is close to 600 ℃and the end temperature of decompositionis somewhat lower when the doping amount of SnO2 is increased.The XRD patterns indicate that the solubility limit of Sn4+ relates directly to the calcining temperature. When being calcined at 700℃,a single phase ITO powder with 15%SnO2(mass fraction)can be obtained.But,when the calcining temperature is higher than 800℃,the phase of SnO2 will appear in ITO nanopowders which contain more than 10%SnO2.The particle size of the ITO nanopowders is 15-25 nm.The ITO nanoparticles without Sn have a spherical shape,but their morphology moves towards an irregular shape when being doped with Sn4+.展开更多
The recycling method and principle of SnO2 from the tin slag of printed circuit boards（PCB） waste were investigated. In this study, pure SnO2 powders were obtained through a multi-step process including ball-milling...The recycling method and principle of SnO2 from the tin slag of printed circuit boards（PCB） waste were investigated. In this study, pure SnO2 powders were obtained through a multi-step process including ball-milling, roasting, dissolving, precipitating, and pickling. The total recovery rate of tin can be up to 91 %. The SnO2 powders obtained is the single phase, and the content of SnO2 is up to 99.9 %. However, the SnO2 particles are easier to agglomerate during the precipitation process. The agglomerate SnO2 particles are about 7.778 lm in mean particle size（D50）. This preparation method presents a viable alternative for the tin slag recycling. The tin is not only recycled, but also reused directly to prepare pure SnO2 powders.展开更多
The conversion of CO_2 to liquid hydrocarbon fuels using solar energy is gaining attraction as a means to deal with climate change and energy depletion,and assessment for related thermochemical cycles has attracted gr...The conversion of CO_2 to liquid hydrocarbon fuels using solar energy is gaining attraction as a means to deal with climate change and energy depletion,and assessment for related thermochemical cycles has attracted great interests in recent years.Here,we perform the thermodynamical analysis on solar-aided CO_2 conversion reactions based on Tin oxides.The equilibrium compositions,production purity and CO_2 conversion are obtained.Also,the variations of conversion efficiency with respect to temperature,normal beam solar insolation,mean flux concentration ratio,initial CO_2 to SnO ratio and heat recuperation percentage are revealed.Our results indicate the initial CO_2 to SnO ratio,χ_(ini),has an evident impact on conversion efficiency andχ_(ini)=0.5,T=700 K andχ_(ini)=1,T=950 K,are favourable for solid C and gaseous CO production,respectively.The calculated maximum cycle efficiency with direct work production is 0.340 at T=950 K andχ_(ini)=1,demonstrating the high conversion efficiency of the proposed system.展开更多
The physico-chemical properties of cesium doped SnO2 nanocrystals synthesized by wet chemical method have been investigated. Scanning electron microscopy （SEM）, X-ray diffraction （XRD）, energy dispersive X-ray ana...The physico-chemical properties of cesium doped SnO2 nanocrystals synthesized by wet chemical method have been investigated. Scanning electron microscopy （SEM）, X-ray diffraction （XRD）, energy dispersive X-ray analysis （EDAX）, inductively coupled plasma （ICP）, atomic absorption spectroscopic （AAS） analyses, UV-vis-NIR spectral studies and dielectric studies were carried out for both pure SnO2 and cesium doped SnO2 nano-samples. All samples of SnO2 did not show any metallic cluster, but the sample containing cesium as a dopant displayed significant activity. The products formed were chloride and water representing a competitive advantage from the stand point of environmental protection.展开更多
This work reports an FTIR study of the NO_x adsorption/desorption cycles on tin oxide nanosized particles under the operating conditions of real sensors (150℃,in presence of O_2).The chemical reactions are monitored...This work reports an FTIR study of the NO_x adsorption/desorption cycles on tin oxide nanosized particles under the operating conditions of real sensors (150℃,in presence of O_2).The chemical reactions are monitored in situ and correlated with the variations of the SnO_2 electrical conductivity.On the basis of the FTIR spectra,two contributing mechanisms for the NO_x detection are suggested.The first one presents the formation of bridged nitrate groups bound to the SnO_2 surface via oxygen vacancies acting as electron donor sites.The second mechanism also involves surface oxygen vacancies in the coordination of NO_x,but this time the formation of NO_x anionic species is considered.Both mechanisms lead to the decrease of the electrical conductivity under NO_x adsorption.However,the bridged nitrate groups are not reversible under gas desorption and thus irreversibly contaminate the surface after the first NO_x adsorption.On the contrary,the nitrosyl anionic species are reversible and,from the second NO_x adsorption/desorption cycle,ensure the reproducibility of the sensor response.展开更多
基金financially supported by Guangdong Province Science and Technology Plan Project for Public Welfare Fund and Ability Construction Project(JCYJ20180301171324915)the National Natural Science Foundation of China(No.21503116)+1 种基金Taishan Scholars Program of Shandong Province(No.tsqn20161004)the Youth 1000 Talent Program of China。
文摘The conversion of carbon dioxide into valuable organic compounds is a highly promising approach to address the energy issues and environmental problems(e.g., global warming). Herein, we presents a facile and efficient method to prepare highly dense and well-dispersed SnO2 nanocrystals on 1 D N-doped carbon nanowires as advanced catalysts for the efficient electroreduction of CO2 to formate. The ultrasmall SnO2 coated on the N-doped carbon nanowires(SnO2@N-CNW) has been synthesized via the simple hydrothermal treatment coupled with a pyrolysis process. The unique structure enables to expose the active tin oxide and also provides the facile pathways for rapid transfer of electron and electrolyte along with the highly porous carbon foam composed with interconnected carbon nanowires. Therefore, SnO2@NCNW electrocatalyst exhibits good durability and high selectivity for formate formation with a Faradaic efficiency of ca. 90%. This work demonstrates a simple method to rationally design high-dense tin oxide nanocrystals on the conductive carbon support as advanced catalysts for CO2 electroreduction.
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.
基金financially supported by International Academic Cooperation and Exchange Program of Shanghai Science and Technology Committee(18160723600)Scientific Research and Technology Development Plan of Guangxi(GUIKE AD17195084)。
文摘It is well-known that the electrolytes can influence the electrochemical reduction of carbon dioxide(ERCO2)in aqueous media.In this work,we explore the effects of alkali metal cations and anions(Li^+,Na^+,K^+,Rb^+,Cs^+,HCO3^-,Cl^-,Br^-,I^-)on the current density and product selectivity for the ERCO2 into formic acid(HCOOH)on the SnO2/carbon paper(Sn O2/C)electrode.Results of the ERCO2 experiments show that for the cations,the promotion effects on current density and faradaic efficiencies(FEs)are in the order of Li^+b Na^+b K^+b Cs^+b Rb^+.For the anions,the current density values are in the order of Na HCO3 b NaClb Na Br b Na I and KHCO3 b KCl≈KI b KBr,respectively,and that on the FEs for the formation of the HCOOH(FEHCOOH)is HCO3-b Cl-b Br-b I-.Based on this result,the effects of alkali metal cations and anions on ERCO2 are discussed.
基金supported by the National Natural Science Foundation of China(51476092)the National High Technology Research and Development Program of China(2011AA060501)Shanxi Province Science and Technology Major Programs(MH2015-06)
文摘The steam regeneration and SO2 regeneration of tin oxide for warm syngas desulfurization is studied in the temperature range of 400-600 ℃. In the steam regeneration, reversible removal of H2S achieved. Regenerated H2S concentration increased with the increasing regeneration temperature. SnO2 sorbent can achieve a complete regeneration by steam at 500 and 600 ℃. In the 502 regeneration, elemental sulfur was produced by the reaction of SnS and SO2. Raising the regeneration temperature （500-600 ℃） or SO2 concentration （1.5-10 vol%） improved the regeneration rate. Under SO2 regeneration at 500 ℃, SnS2 formed in the sorbent due to the interconversion of tin sulfides. Under steam regeneration or SO2 regeneration, the cyclic breakthrough sulfur capacity of SnO2 sorbent decreased because of the sintering caused by low melting component SnS. A two-stage regeneration process was applied to recover the elemental sulfur which achieved a complete regeneration.
基金Project(U0837604)supported by the Natural Science Foundation of Yunnan Province,ChinaProject(07C40291)supported by Research Fund of Yunnan Education Department,ChinaProject(2007003)supported by Research Fund of Kunming University of Science and Technology,China
文摘Indium tin oxide(ITO)nanopowders were prepared by a modified chemical co-precipitation process.The influence of different SnO2 contents on the decomposition behavior of ITO precursors,and on the phase and morphology of ITO precursors and ITO nanopowders were studied by X-ray diffractometry,transmission electron microscopy and differential thermal and thermogravimetry analysis methods.The TG-DSC curves show that the decomposition process of precursor precipitation is completed when the temperature is close to 600 ℃and the end temperature of decompositionis somewhat lower when the doping amount of SnO2 is increased.The XRD patterns indicate that the solubility limit of Sn4+ relates directly to the calcining temperature. When being calcined at 700℃,a single phase ITO powder with 15%SnO2(mass fraction)can be obtained.But,when the calcining temperature is higher than 800℃,the phase of SnO2 will appear in ITO nanopowders which contain more than 10%SnO2.The particle size of the ITO nanopowders is 15-25 nm.The ITO nanoparticles without Sn have a spherical shape,but their morphology moves towards an irregular shape when being doped with Sn4+.
基金financially supported by the National Natural Science Foundation of China(NSFC,U21A20500,52072115,51972102)the Natural Science Project of Hubei Province in China(2023AFB758,2022CFB518)。
基金financially supported by the Beijing Nova Program (No. Z141103001814006)the National Key Technology R&D Program (Nos. 2012BAC12B05 and 2012BAC02B01)+1 种基金the National Natural Science Foundation of China (Nos. 51174247 and U1360202)the National High-Tech Research and the Development Program of China (No. 2012AA063202)
文摘The recycling method and principle of SnO2 from the tin slag of printed circuit boards（PCB） waste were investigated. In this study, pure SnO2 powders were obtained through a multi-step process including ball-milling, roasting, dissolving, precipitating, and pickling. The total recovery rate of tin can be up to 91 %. The SnO2 powders obtained is the single phase, and the content of SnO2 is up to 99.9 %. However, the SnO2 particles are easier to agglomerate during the precipitation process. The agglomerate SnO2 particles are about 7.778 lm in mean particle size（D50）. This preparation method presents a viable alternative for the tin slag recycling. The tin is not only recycled, but also reused directly to prepare pure SnO2 powders.
基金supported by the National Natural Science Foundation of China (Grant No. 51476163)the Institute of Electrical Engineering, Chinese Academy of Sciences (Grant No. Y770111CSC)
文摘The conversion of CO_2 to liquid hydrocarbon fuels using solar energy is gaining attraction as a means to deal with climate change and energy depletion,and assessment for related thermochemical cycles has attracted great interests in recent years.Here,we perform the thermodynamical analysis on solar-aided CO_2 conversion reactions based on Tin oxides.The equilibrium compositions,production purity and CO_2 conversion are obtained.Also,the variations of conversion efficiency with respect to temperature,normal beam solar insolation,mean flux concentration ratio,initial CO_2 to SnO ratio and heat recuperation percentage are revealed.Our results indicate the initial CO_2 to SnO ratio,χ_(ini),has an evident impact on conversion efficiency andχ_(ini)=0.5,T=700 K andχ_(ini)=1,T=950 K,are favourable for solid C and gaseous CO production,respectively.The calculated maximum cycle efficiency with direct work production is 0.340 at T=950 K andχ_(ini)=1,demonstrating the high conversion efficiency of the proposed system.
文摘The physico-chemical properties of cesium doped SnO2 nanocrystals synthesized by wet chemical method have been investigated. Scanning electron microscopy （SEM）, X-ray diffraction （XRD）, energy dispersive X-ray analysis （EDAX）, inductively coupled plasma （ICP）, atomic absorption spectroscopic （AAS） analyses, UV-vis-NIR spectral studies and dielectric studies were carried out for both pure SnO2 and cesium doped SnO2 nano-samples. All samples of SnO2 did not show any metallic cluster, but the sample containing cesium as a dopant displayed significant activity. The products formed were chloride and water representing a competitive advantage from the stand point of environmental protection.
文摘This work reports an FTIR study of the NO_x adsorption/desorption cycles on tin oxide nanosized particles under the operating conditions of real sensors (150℃,in presence of O_2).The chemical reactions are monitored in situ and correlated with the variations of the SnO_2 electrical conductivity.On the basis of the FTIR spectra,two contributing mechanisms for the NO_x detection are suggested.The first one presents the formation of bridged nitrate groups bound to the SnO_2 surface via oxygen vacancies acting as electron donor sites.The second mechanism also involves surface oxygen vacancies in the coordination of NO_x,but this time the formation of NO_x anionic species is considered.Both mechanisms lead to the decrease of the electrical conductivity under NO_x adsorption.However,the bridged nitrate groups are not reversible under gas desorption and thus irreversibly contaminate the surface after the first NO_x adsorption.On the contrary,the nitrosyl anionic species are reversible and,from the second NO_x adsorption/desorption cycle,ensure the reproducibility of the sensor response.
