A series of CuO/Ce1-xZrxO2 catalysts(x=0.2,0.4,0.6 and 0.8)are applied to elaborate the effect of the Zr/Ce ratio on the catalytic performance of CO2 hydrogenation to CH3OH.The best catalytic performance is achieved w...A series of CuO/Ce1-xZrxO2 catalysts(x=0.2,0.4,0.6 and 0.8)are applied to elaborate the effect of the Zr/Ce ratio on the catalytic performance of CO2 hydrogenation to CH3OH.The best catalytic performance is achieved with CuO/Ce0.4Zr0.6O2,exhibiting XCO2=13.2%and YCH3OH=9.47%(T=280℃,P=3 MPa).The formation of dispersed surface CuO species and larger number of oxygen vacancies are detected over CuO/Ce0.4Zr0.6O2 due to stronger interaction between CuO and Ce0.4Zr0.6O2,resulting in the superior activation ability for H2 and CO2 respectively.Additionally,the evidence is provided by in situ DRIFTS under the activity test pressure(3 MPa)that bi/m-HCOO* species are preferable for accumulating over ceria-rich(CuO/Ce0.6Zr0.4O2 and CuO/Ce0.8Zr0.2O2)catalysts while zirconia-rich(CuO/Ce0.4Zr0.6O2 and CuO/Ce0.2Zr0.8O2)catalysts are benefit to encourage the transformation of bi/m-HCOO* species to CH3OH.The abundant population and high activity of intermediate species over CuO/Ce0.4Zr0.6O2 give a strong positive effect on the catalytic performance.展开更多
The Co-incorporated Ce1-xZrxO2 catalysts were prepared by co-precipitation for carbon dioxide reforming of methane.The ratio of Ce to Zr was varied to optimize the performances of co-precipitated Co-Ce-Zr-Ox catalysts...The Co-incorporated Ce1-xZrxO2 catalysts were prepared by co-precipitation for carbon dioxide reforming of methane.The ratio of Ce to Zr was varied to optimize the performances of co-precipitated Co-Ce-Zr-Ox catalysts.The prepared catalysts were characterized by various physico-chemical characterization techniques including TPR,X-ray diffraction,N2 adsorption at low temperature,XPS and CO2-TPSR.The co-precipitated Co-Ce0.8Zr0.2O2 sample containing 16% CoO exhibited a higher catalytic activity among the five catalysts,and the activity was maintained without significant loss during the reaction for 60 h.Under the conditions of 750 ℃,0.1 MPa,36000 ml/（h gcat）,and CO2/CH4 molar ratio of 1：1,the CO2 conversion over this catalyst was 75% while the CH4 conversion was 67%.The cubic Ce0.8Zr0.2O2 facilitated a higher dispersion and a higher reducibility of the cobalt component,and the apparent activation energy for Co-Ce0.8Zr0.2O2 sample was 49.1 kJ/mol in the CO2/CH4 reforming reaction.As a result,the Co-Ce0.8Zr0.2O2 sample exhibited a higher activity and stability for the reforming of CH4 with CO2.展开更多
基金financially supported by the National Nature Science Foundation of China (21876019, 21577014)Strategic Priority Research Program of the Chinese Academy of Sciences (XDB17020000)the fund of the State Key Laboratory of Catalysis in DICP (N18-08)。
文摘A series of CuO/Ce1-xZrxO2 catalysts(x=0.2,0.4,0.6 and 0.8)are applied to elaborate the effect of the Zr/Ce ratio on the catalytic performance of CO2 hydrogenation to CH3OH.The best catalytic performance is achieved with CuO/Ce0.4Zr0.6O2,exhibiting XCO2=13.2%and YCH3OH=9.47%(T=280℃,P=3 MPa).The formation of dispersed surface CuO species and larger number of oxygen vacancies are detected over CuO/Ce0.4Zr0.6O2 due to stronger interaction between CuO and Ce0.4Zr0.6O2,resulting in the superior activation ability for H2 and CO2 respectively.Additionally,the evidence is provided by in situ DRIFTS under the activity test pressure(3 MPa)that bi/m-HCOO* species are preferable for accumulating over ceria-rich(CuO/Ce0.6Zr0.4O2 and CuO/Ce0.8Zr0.2O2)catalysts while zirconia-rich(CuO/Ce0.4Zr0.6O2 and CuO/Ce0.2Zr0.8O2)catalysts are benefit to encourage the transformation of bi/m-HCOO* species to CH3OH.The abundant population and high activity of intermediate species over CuO/Ce0.4Zr0.6O2 give a strong positive effect on the catalytic performance.
文摘The Co-incorporated Ce1-xZrxO2 catalysts were prepared by co-precipitation for carbon dioxide reforming of methane.The ratio of Ce to Zr was varied to optimize the performances of co-precipitated Co-Ce-Zr-Ox catalysts.The prepared catalysts were characterized by various physico-chemical characterization techniques including TPR,X-ray diffraction,N2 adsorption at low temperature,XPS and CO2-TPSR.The co-precipitated Co-Ce0.8Zr0.2O2 sample containing 16% CoO exhibited a higher catalytic activity among the five catalysts,and the activity was maintained without significant loss during the reaction for 60 h.Under the conditions of 750 ℃,0.1 MPa,36000 ml/（h gcat）,and CO2/CH4 molar ratio of 1：1,the CO2 conversion over this catalyst was 75% while the CH4 conversion was 67%.The cubic Ce0.8Zr0.2O2 facilitated a higher dispersion and a higher reducibility of the cobalt component,and the apparent activation energy for Co-Ce0.8Zr0.2O2 sample was 49.1 kJ/mol in the CO2/CH4 reforming reaction.As a result,the Co-Ce0.8Zr0.2O2 sample exhibited a higher activity and stability for the reforming of CH4 with CO2.
