Tin/tin oxide materials are key electrocatalysts for selective conversion of CO;to formate/formic acid.Herein we report a tin oxide material with nitrogen doping by using ammonia treatment at elevated temperature. The...Tin/tin oxide materials are key electrocatalysts for selective conversion of CO;to formate/formic acid.Herein we report a tin oxide material with nitrogen doping by using ammonia treatment at elevated temperature. The N doped material demonstrated enhanced electrocatalytic CO;reduction activity, showing high Faradaic efficiency（90%） for formate at -0.65 V vs. RHE with partial current density of 4 mA/cm;.The catalysis was contributed to increased electron negativity of N atom compared to O atom. Additionally, the N-doped catalyst demonstrates sulfur tolerance with retained formate selectivity. The analysis after electrolysis shows that the catalyst structure partially converts to metallic Sn, and thus the combined Sn/N-SnO;is the key for the active CO;catalysis.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
Electrochemical CO_(2)reduction to formate is a promising approach to store renewable electricity and utilize CO_(2).Tin oxide catalysts are efficient catalysts for this process,while the mechanisms underneath,especia...Electrochemical CO_(2)reduction to formate is a promising approach to store renewable electricity and utilize CO_(2).Tin oxide catalysts are efficient catalysts for this process,while the mechanisms underneath,especially the existence and role of oxidized tin species under CO2 electroreduction conditions remain unclear.In this work,we provide strong evidence on the presence of oxidized tin species on both SnO_(2)and Sn during CO_(2)reduction via in situ surface‐enhanced Raman spectroscopy,while in different nature.Reactivity measurements show similar activity and selectivity to formate production on SnO_(2)and Sn catalysts.Combined analysis of Raman spectra and reactivity results suggests that Sn(IV)and Sn(II)oxide species are unlikely the catalytic species in CO_(2)electroreduction to formate.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 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
Density functional theory calculations were used to unravel the mechanism of CO_2 electroreduction on SnO_x surfaces. Under highly reducing conditions(<-0.6 V vs. RHE), the SnO(101) surface with oxygen vacancies is...Density functional theory calculations were used to unravel the mechanism of CO_2 electroreduction on SnO_x surfaces. Under highly reducing conditions(<-0.6 V vs. RHE), the SnO(101) surface with oxygen vacancies is likely the active phase for CO_2 reduction. We showed that the proton-electron transfer to adsorbed *CO_2 forming *OCHO, a key intermediate for producing HCOOH, is energetically more favorable than the formation of *COOH, justifying the selectivity trends observed on Sn-based electrocatalysts. With linear scaling relations, we propose the free formation energy of *CO_2 at the oxygen vacancy as the reactivity descriptor. By engineering the strain of the SnO(101) surface, the selectivity towards HCOOH can be further optimized at reduced overpotentials.展开更多
Antimony sulfide(Sb_(2)S_(3))is an appealing semiconductor as light absorber for solar cells due to its high absorption coefficient,appropriate band gap(~1.7 e V)and abundance of constituent elements.However,power con...Antimony sulfide(Sb_(2)S_(3))is an appealing semiconductor as light absorber for solar cells due to its high absorption coefficient,appropriate band gap(~1.7 e V)and abundance of constituent elements.However,power conversion efficiency(PCE)of Sb_(2)S_(3)-based solar cells still lags much behind the theoretically predicted due to the imperfect energy level alignment at the charge transporting layer/Sb_(2)S_(3)interfaces and hence severe charge recombination.Herein,we insert a high-temperature sintered magnesium(Mg)-doped tin oxide(SnO_(2))layer between cadmium sulfide(Cd S)and fuorine doped tin oxide to form a cascaded energy level alignment and thus mitigate interfacial charge recombination.Simultaneously,the inserted Mg-doped Sn O_(2)buffer layer facilitates the growth of the neibouring Cd S film with orientation followed by Sb_(2)S_(3)film with larger grains and fewer pinholes.Consequently,the resultant Sb_(2)S_(3)solar cells with Mg-doped SnO_(2)deliver a champion PCE of 6.31%,22.8%higher than those without a buffer layer.Our work demonstrates that deliberate absorber growth as well as efficient hole blocking upon an appropriate buffer layer is viable in obtaining solution-processed Sb_(2)S_(3)solar cells with high performance.展开更多
The development of high-performance electrocatalysts holds the decisive key to the electrochemical CO2 reduction toward value-added products. Formic acid or formate is a desirable reduction product, but its selective ...The development of high-performance electrocatalysts holds the decisive key to the electrochemical CO2 reduction toward value-added products. Formic acid or formate is a desirable reduction product, but its selective production is often challenging. Tin based-materials have attracted great attention for formate production, and yet their performances are far from satisfactory. In this study, we reported the preparation of SnO2 nanoclusters from the controlled self-polymerization of dopamine together with SnO32-, followed by the mild-temperature calcination. The final product consisted of large primary particles that were further made of small secondary SnO2 nanocrystals. When evaluated as the electrocatalyst for CO2 reduction in 0.5 M NaHCO3, our material exhibited impressive activity, selectivity and stability for the selective CO2 reduction to formate. A peak formate Faradaic efficiency of^73% and large partial current density of 16.3 mA/cm2 was achieved at -0.92 V versus reversible hydrogen electrode.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
Thin layer polycrystal oxides (amorphous and micro-crystalline) TiO2(Fe2O3, SnO2 and ln2O3 · Sn) are prepared by the organometallic chemical vapor deposition (MO-CVD) technique at 300-410℃ . Their structures, su...Thin layer polycrystal oxides (amorphous and micro-crystalline) TiO2(Fe2O3, SnO2 and ln2O3 · Sn) are prepared by the organometallic chemical vapor deposition (MO-CVD) technique at 300-410℃ . Their structures, surface states and photoelectrochemical properties are described by X-ray diffraction (XRD), electron microscopy and three electrode methods. The experiments indicate that these thin layer oxides are suitable for formly transparent conductive coating to serve as photoelectrodes and photocatalysts for splitting of water.展开更多
Polycrystalline SnO2 fine powder consisting of nano-particles （SnO2-NP）, SnO2 nano-sheets （SnO2-NS）, and SnO2 containing both nano-rods and nano-particles （SnO2-NR＋NP） were prepared and used for CO oxidation. S...Polycrystalline SnO2 fine powder consisting of nano-particles （SnO2-NP）, SnO2 nano-sheets （SnO2-NS）, and SnO2 containing both nano-rods and nano-particles （SnO2-NR＋NP） were prepared and used for CO oxidation. SnO2-NS possesses a mesoporous structure and has a higher surface area, larger pore volume, and more active species than SnO2-NP, and shows improved activity. In contrast, although SnO2-NR＋NP has only a slightly higher surface area and pore volume, and slightly more active surface oxygen species than SnO2-NP, it has more exposed active （110） facets, which is the reason for its improved oxidation activity. Water vapor has only a reversible and weak influence on SnO2-NS, therefore it is a potential catalyst for emission control processes.展开更多
基金financially supported by Key Research Program of the Chinese Academy of Sciences (ZDRW-ZS-2016-3)the National Key Research and Development Program of China (2016YFB0600901)the Instrument Developing Project of the Chinese Academy of Sciences
文摘Tin/tin oxide materials are key electrocatalysts for selective conversion of CO;to formate/formic acid.Herein we report a tin oxide material with nitrogen doping by using ammonia treatment at elevated temperature. The N doped material demonstrated enhanced electrocatalytic CO;reduction activity, showing high Faradaic efficiency（90%） for formate at -0.65 V vs. RHE with partial current density of 4 mA/cm;.The catalysis was contributed to increased electron negativity of N atom compared to O atom. Additionally, the N-doped catalyst demonstrates sulfur tolerance with retained formate selectivity. The analysis after electrolysis shows that the catalyst structure partially converts to metallic Sn, and thus the combined Sn/N-SnO;is the key for the active CO;catalysis.
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Electrochemical CO_(2)reduction to formate is a promising approach to store renewable electricity and utilize CO_(2).Tin oxide catalysts are efficient catalysts for this process,while the mechanisms underneath,especially the existence and role of oxidized tin species under CO2 electroreduction conditions remain unclear.In this work,we provide strong evidence on the presence of oxidized tin species on both SnO_(2)and Sn during CO_(2)reduction via in situ surface‐enhanced Raman spectroscopy,while in different nature.Reactivity measurements show similar activity and selectivity to formate production on SnO_(2)and Sn catalysts.Combined analysis of Raman spectra and reactivity results suggests that Sn(IV)and Sn(II)oxide species are unlikely the catalytic species in CO_(2)electroreduction to formate.
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financial support from the American Chemical Society Petroleum Research Fund (ACS PRF 55581-DNI5)the Institute for Critical Technology and Applied Science (ICTAS-J0663175)the NSF CBET Catalysis and Biocatalysis Program (CBET-1604984)
文摘Density functional theory calculations were used to unravel the mechanism of CO_2 electroreduction on SnO_x surfaces. Under highly reducing conditions(<-0.6 V vs. RHE), the SnO(101) surface with oxygen vacancies is likely the active phase for CO_2 reduction. We showed that the proton-electron transfer to adsorbed *CO_2 forming *OCHO, a key intermediate for producing HCOOH, is energetically more favorable than the formation of *COOH, justifying the selectivity trends observed on Sn-based electrocatalysts. With linear scaling relations, we propose the free formation energy of *CO_2 at the oxygen vacancy as the reactivity descriptor. By engineering the strain of the SnO(101) surface, the selectivity towards HCOOH can be further optimized at reduced overpotentials.
基金supported by the National Natural Science Foundation of China(Grant Nos.62074117,61904126)the Natural Science Foundation of Hubei Province,China(Grant Nos.2019AAA020,2019CFB122)+2 种基金the Natural Science Foundation of Guangdong Province(2021A1515012594)Guangdong Province Office of Education(2020ZDZX2028)the Special Funds for the Development of Strategic Emerging Industries in Shenzhen(JCYJ20190808152609307)。
文摘Antimony sulfide(Sb_(2)S_(3))is an appealing semiconductor as light absorber for solar cells due to its high absorption coefficient,appropriate band gap(~1.7 e V)and abundance of constituent elements.However,power conversion efficiency(PCE)of Sb_(2)S_(3)-based solar cells still lags much behind the theoretically predicted due to the imperfect energy level alignment at the charge transporting layer/Sb_(2)S_(3)interfaces and hence severe charge recombination.Herein,we insert a high-temperature sintered magnesium(Mg)-doped tin oxide(SnO_(2))layer between cadmium sulfide(Cd S)and fuorine doped tin oxide to form a cascaded energy level alignment and thus mitigate interfacial charge recombination.Simultaneously,the inserted Mg-doped Sn O_(2)buffer layer facilitates the growth of the neibouring Cd S film with orientation followed by Sb_(2)S_(3)film with larger grains and fewer pinholes.Consequently,the resultant Sb_(2)S_(3)solar cells with Mg-doped SnO_(2)deliver a champion PCE of 6.31%,22.8%higher than those without a buffer layer.Our work demonstrates that deliberate absorber growth as well as efficient hole blocking upon an appropriate buffer layer is viable in obtaining solution-processed Sb_(2)S_(3)solar cells with high performance.
基金supports from the National Natural Science Foundation of China (51472173 and 51522208)the Natural Science Foundation of Jiangsu Province (SBK2015010320)the Priority Academic Program Development of Jiangsu Higher Education Institutions and Collaborative Innovation Center of Suzhou Nano Science and Technology
文摘The development of high-performance electrocatalysts holds the decisive key to the electrochemical CO2 reduction toward value-added products. Formic acid or formate is a desirable reduction product, but its selective production is often challenging. Tin based-materials have attracted great attention for formate production, and yet their performances are far from satisfactory. In this study, we reported the preparation of SnO2 nanoclusters from the controlled self-polymerization of dopamine together with SnO32-, followed by the mild-temperature calcination. The final product consisted of large primary particles that were further made of small secondary SnO2 nanocrystals. When evaluated as the electrocatalyst for CO2 reduction in 0.5 M NaHCO3, our material exhibited impressive activity, selectivity and stability for the selective CO2 reduction to formate. A peak formate Faradaic efficiency of^73% and large partial current density of 16.3 mA/cm2 was achieved at -0.92 V versus reversible hydrogen electrode.
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.
基金Supported by the National Natural Science Foundation of China.
文摘Thin layer polycrystal oxides (amorphous and micro-crystalline) TiO2(Fe2O3, SnO2 and ln2O3 · Sn) are prepared by the organometallic chemical vapor deposition (MO-CVD) technique at 300-410℃ . Their structures, surface states and photoelectrochemical properties are described by X-ray diffraction (XRD), electron microscopy and three electrode methods. The experiments indicate that these thin layer oxides are suitable for formly transparent conductive coating to serve as photoelectrodes and photocatalysts for splitting of water.
基金supported by the National Natural Science Foundation of China (21263015)the Education Department of Jiangxi Province (KJLD14005)the Natural Science Foundation of Jiangxi Province(20151BBE50006,20122BAB203009)~~
文摘Polycrystalline SnO2 fine powder consisting of nano-particles （SnO2-NP）, SnO2 nano-sheets （SnO2-NS）, and SnO2 containing both nano-rods and nano-particles （SnO2-NR＋NP） were prepared and used for CO oxidation. SnO2-NS possesses a mesoporous structure and has a higher surface area, larger pore volume, and more active species than SnO2-NP, and shows improved activity. In contrast, although SnO2-NR＋NP has only a slightly higher surface area and pore volume, and slightly more active surface oxygen species than SnO2-NP, it has more exposed active （110） facets, which is the reason for its improved oxidation activity. Water vapor has only a reversible and weak influence on SnO2-NS, therefore it is a potential catalyst for emission control processes.
