This work aims to study the effect of redox property and surface morphology of perovskite oxides on the catalytic activity of CO oxidation and CO+NO reduction, with the redox property being tuned by doping Fe at the ...This work aims to study the effect of redox property and surface morphology of perovskite oxides on the catalytic activity of CO oxidation and CO+NO reduction, with the redox property being tuned by doping Fe at the Co site of La0.8Sr0.2Co1-xFexO3 and the surface morphology being modified by supporting La0.8Sr0.2CoO3 on various mesoporous silicas(i.e., SBA-16, SBA-15, MCF). Characteristic results show that the Fe doping improves the match of redox potentials, and SBA-16 is the best support of La0.8Sr0.2CoO3 when referring to the oxidation ability(e.g., the Co^3+/Co^2+ molar ratio). A mechanism for oxygen desorption from perovskite oxides is proposed based on O2-TPD experiments, showing the evolution process of oxygen released from oxygen vacancy and lattice framework. Catalytic tests indicate that La0.8Sr0.2CoO3 is the best for CO oxidation, and La0.8Sr0.2FeO3 is the best for CO+NO reduction. The mechanism of CO+NO reduction changes as the reaction temperature increases, with XNO/XCO value decreases from 2.4 at 250℃ to 1.0 at 400℃. As for the surface morphology, La0. Sr0.2CoO3 supported on SBA-16 possesses the highest surface Co^3+/Co^2+ molar ratio as compared to the other two, and shows the best activity for CO oxidation.展开更多
基金Supported by the National Natural Science Foundation of China(No.21203254), the Natural Science Foundation of Hubei Province of China(No.2015CFA138), the Natttral Science Foundation of Liaoning Province of Ctfina(No.201602681), the Shenyang Municipal Science and Technology Planning Project, China(No.17-76-1-00) and the Shenyang Normal University Excellent Talent Support Program, China(No.51600203).
文摘This work aims to study the effect of redox property and surface morphology of perovskite oxides on the catalytic activity of CO oxidation and CO+NO reduction, with the redox property being tuned by doping Fe at the Co site of La0.8Sr0.2Co1-xFexO3 and the surface morphology being modified by supporting La0.8Sr0.2CoO3 on various mesoporous silicas(i.e., SBA-16, SBA-15, MCF). Characteristic results show that the Fe doping improves the match of redox potentials, and SBA-16 is the best support of La0.8Sr0.2CoO3 when referring to the oxidation ability(e.g., the Co^3+/Co^2+ molar ratio). A mechanism for oxygen desorption from perovskite oxides is proposed based on O2-TPD experiments, showing the evolution process of oxygen released from oxygen vacancy and lattice framework. Catalytic tests indicate that La0.8Sr0.2CoO3 is the best for CO oxidation, and La0.8Sr0.2FeO3 is the best for CO+NO reduction. The mechanism of CO+NO reduction changes as the reaction temperature increases, with XNO/XCO value decreases from 2.4 at 250℃ to 1.0 at 400℃. As for the surface morphology, La0. Sr0.2CoO3 supported on SBA-16 possesses the highest surface Co^3+/Co^2+ molar ratio as compared to the other two, and shows the best activity for CO oxidation.