Activated carbon （AC） supported silver catalysts were prepared by incipient wetness impregnation method and their catalytic performance for CO preferential oxidation （PROX） in excess H2 was evaluated. Ag/AC cataly...Activated carbon （AC） supported silver catalysts were prepared by incipient wetness impregnation method and their catalytic performance for CO preferential oxidation （PROX） in excess H2 was evaluated. Ag/AC catalysts, after reduction in H2 at low temperatures （≤200 ℃） following heat treatment in He at 200 ℃ （He200H200）, exhibited the best catalytic properties. Temperature-programmed desorption （TPD）, X-ray diffraction （XRD） and temperature-programmed reduction （TPR） results indicated that silver oxides were produced during heat treatment in He at 200 ℃ which were reduced to metal silver nanoparticles in H2 at low temperatures （≤200 ℃）, simultaneously generating the adsorbed water/OH. CO conversion was enhanced 40% after water treatment following heat treatment in He at 600 ℃. These results imply that the metal silver nanoparticles are the active species and the adsorbed water/OH has noticeable promotion effects on CO oxidation. However, the promotion effect is still limited compared to gold catalysts under the similar conditions, which may be the reason of low selectivity to CO oxidation in PROX over silver catalysts. The reported Ag/AC-S-He catalyst after He200H200 treatment displayed similar PROX of CO reaction properties to Ag/SiO2. This means that Ag/AC catalyst is also an efficient low-temperature CO oxidation catalyst.展开更多
Preferential oxidation of CO(CO-PROX)in H_(2)-rich streams is highly important for purifying the industrial grade H_(2)used in proton-exchange-membrane fuel cells(PEMFC),but it is still limited to a relatively narrow ...Preferential oxidation of CO(CO-PROX)in H_(2)-rich streams is highly important for purifying the industrial grade H_(2)used in proton-exchange-membrane fuel cells(PEMFC),but it is still limited to a relatively narrow operation temperature window.In this study,the trace amounts of Cu are used to modify a Pt/Al_(2)O_(3)catalyst.The introduced Cu_(2+)species are atomically anchored on Pt nanoparticles through strong electrostatic adsorption.展开更多
Multi-walled carbon nanotubes （MWCNT） supported Cu-Co composite oxides catalysts were prepared by an ultrasonication treatment-aided impregnation method. The structure prop-erties of the catalysts were characterized...Multi-walled carbon nanotubes （MWCNT） supported Cu-Co composite oxides catalysts were prepared by an ultrasonication treatment-aided impregnation method. The structure prop-erties of the catalysts were characterized by XRD, TEM, H2-TPR, XPS and Raman spectra, indicating the strong interactions between Cu and Co mixed oxides as well as between metal oxides and MWCNT support. The catalytic performance of CO removal in a H2-rich stream was examined. In contrast to the single Cu and Co catalyst, the unique performance was ob-served for Cu-Co composite catalysts, which features an unusual reaction pathway through the combination of CO preferential oxidation and CO methanation especially at high reac-tion temperature. The optimal catalyst with Cu/Co ratio of 1/8 can achieve the complete CO conversion in a wider temperature range of 150-250 ℃ under the space velocity as high as 120 L/（h·g）, which demonstrates a promising catalyst for the e ective CO removal in a H2-rich stream.展开更多
Gold-based catalysts are promising in CO preferential oxidation(CO-PROX)reaction in H_(2)-rich stream on account of their high intrinsic activity for CO elimination even at ambient temperature.However,the decrease of ...Gold-based catalysts are promising in CO preferential oxidation(CO-PROX)reaction in H_(2)-rich stream on account of their high intrinsic activity for CO elimination even at ambient temperature.However,the decrease of CO conversion at elevated temperature due to the competition of H_(2)oxidation,together with the low stability of gold nanoparticles,has posed a dear challenge.Herein,we report that Au-Cu bimetallic catalyst prepared by galvanic replacement method shows a wide temperature window for CO total conversion(30-100℃)and very good catalyst stability without deactivation in a 200-h test.Detailed characterizations combined with density functional theory(DFT)calculation reveal that the synergistic effect of Au-Cu,the electron transfer from Au to Cu,leads to not only strengthened chemisorption of CO but also weakened dissociation of H_(2),both of which are helpful in inhibiting the competition of H_(2)oxidation thus widening the temperature window for CO total conversion.展开更多
基金supported by the National Natural Science Foundation of China (No. 21207039)the Natural Science Foundation of Guangdong Province, China (Grant No. S2011010000737)+2 种基金the Doctoral Fund of Ministry of Education of China (20110172120017)the Fundamental Research Funds for the Central Universities (Grant No. 2011zm 0048)the Key Laboratory of Renewable Energy and Gas Hydrate, Chinese Academy of Sciences (No. Y007K1)
文摘Activated carbon （AC） supported silver catalysts were prepared by incipient wetness impregnation method and their catalytic performance for CO preferential oxidation （PROX） in excess H2 was evaluated. Ag/AC catalysts, after reduction in H2 at low temperatures （≤200 ℃） following heat treatment in He at 200 ℃ （He200H200）, exhibited the best catalytic properties. Temperature-programmed desorption （TPD）, X-ray diffraction （XRD） and temperature-programmed reduction （TPR） results indicated that silver oxides were produced during heat treatment in He at 200 ℃ which were reduced to metal silver nanoparticles in H2 at low temperatures （≤200 ℃）, simultaneously generating the adsorbed water/OH. CO conversion was enhanced 40% after water treatment following heat treatment in He at 600 ℃. These results imply that the metal silver nanoparticles are the active species and the adsorbed water/OH has noticeable promotion effects on CO oxidation. However, the promotion effect is still limited compared to gold catalysts under the similar conditions, which may be the reason of low selectivity to CO oxidation in PROX over silver catalysts. The reported Ag/AC-S-He catalyst after He200H200 treatment displayed similar PROX of CO reaction properties to Ag/SiO2. This means that Ag/AC catalyst is also an efficient low-temperature CO oxidation catalyst.
基金financially supported by the National Key Research and Development Program of China(No.2022YFB3504200)the National Natural Science Foundation of China(Nos.U21A20326 and 22376063)+4 种基金the fund of the National Engineering Laboratory for Mobile Source Emission Control Technology(No.NELMS2020A05)the Fundamental Research Funds for the Central Universitiesthe funding received from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 897197.Y.L.(CSC No.202006740085)is grateful for thegrant from the China Scholarship Councilthe ICREA Academia program and grants MICINN/FEDER PID2021124572OB-C31 and GC 2021 SGR 01061part of Maria de Maeztu Units of Excellence Programme CEX2023-001300-M/funded by MCIN/AEI/https://doi.org/10.13039/501100011033
文摘Preferential oxidation of CO(CO-PROX)in H_(2)-rich streams is highly important for purifying the industrial grade H_(2)used in proton-exchange-membrane fuel cells(PEMFC),but it is still limited to a relatively narrow operation temperature window.In this study,the trace amounts of Cu are used to modify a Pt/Al_(2)O_(3)catalyst.The introduced Cu_(2+)species are atomically anchored on Pt nanoparticles through strong electrostatic adsorption.
文摘Multi-walled carbon nanotubes （MWCNT） supported Cu-Co composite oxides catalysts were prepared by an ultrasonication treatment-aided impregnation method. The structure prop-erties of the catalysts were characterized by XRD, TEM, H2-TPR, XPS and Raman spectra, indicating the strong interactions between Cu and Co mixed oxides as well as between metal oxides and MWCNT support. The catalytic performance of CO removal in a H2-rich stream was examined. In contrast to the single Cu and Co catalyst, the unique performance was ob-served for Cu-Co composite catalysts, which features an unusual reaction pathway through the combination of CO preferential oxidation and CO methanation especially at high reac-tion temperature. The optimal catalyst with Cu/Co ratio of 1/8 can achieve the complete CO conversion in a wider temperature range of 150-250 ℃ under the space velocity as high as 120 L/（h·g）, which demonstrates a promising catalyst for the e ective CO removal in a H2-rich stream.
基金This work was financially supported by the“Transformational Technologies for Clean Energy and Demonstration”,the Strategic Priority Research Program of the Chinese Academy of Sciences(CAS,No.XDA21030900)DNL Cooperation Fund,CAS(No.DNL201903)the National Natural Science Foundation of China(No.51701201).
文摘Gold-based catalysts are promising in CO preferential oxidation(CO-PROX)reaction in H_(2)-rich stream on account of their high intrinsic activity for CO elimination even at ambient temperature.However,the decrease of CO conversion at elevated temperature due to the competition of H_(2)oxidation,together with the low stability of gold nanoparticles,has posed a dear challenge.Herein,we report that Au-Cu bimetallic catalyst prepared by galvanic replacement method shows a wide temperature window for CO total conversion(30-100℃)and very good catalyst stability without deactivation in a 200-h test.Detailed characterizations combined with density functional theory(DFT)calculation reveal that the synergistic effect of Au-Cu,the electron transfer from Au to Cu,leads to not only strengthened chemisorption of CO but also weakened dissociation of H_(2),both of which are helpful in inhibiting the competition of H_(2)oxidation thus widening the temperature window for CO total conversion.
