The structure and catalytic properties of SrTiO3 perovskite-type oxide catalysts for oxidative coupling of methane (OCM) have been studied by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and m...The structure and catalytic properties of SrTiO3 perovskite-type oxide catalysts for oxidative coupling of methane (OCM) have been studied by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and microreactor tests. It has been shown that OCM catalytic properties of SrTiO3 catalysts are correlated to the Sr/Ti atomic ratio. Increasing Sr/Ti ratio in the perovskite?-type SrTiO3 catalysts results in the surface enrichment of Sr element, leading to the the higher content of adsorbed oxygen species on the surface of catalysts and thus higher C2 selectivity for OCM reaction.展开更多
The structure and catalytic properties of SrTi1- xMgxO3- δ perovskite type catalysts for oxidative coupling of methane (OCM) have been studied by using X ray diffraction (XRD), X ray photoelectron spectroscopy (XPS) ...The structure and catalytic properties of SrTi1- xMgxO3- δ perovskite type catalysts for oxidative coupling of methane (OCM) have been studied by using X ray diffraction (XRD), X ray photoelectron spectroscopy (XPS) and Temperature programmed desorption (O2 TPD) methods. It has been shown that doping Mg2+ cations to the B site of SrTi1- xMgxO3- δ perovskite type catalysts results in the formation of oxygen vacancies in the lattices of oxide catalysts. With increasing the amount of Mg2+ doped in the B site of SrTi1- xMgxO3- δ , methane conversion and C2 selectivity first increase and then decrease remarkably. The SrTi1- xMgxO3- δ catalyst with x=0.1 has the highest methane conversion and C2 yield. It is suggested that the oxygen vacancies produced by Mg2+ cations doping are the sites responsible for oxygen activation, and the adsorbed oxygen species on the surface of SrTi1- xMgxO3- δ catalysts are the main active species for OCM reaction. However, the over high content of the adsorbed oxygen species on the surface results in the complete oxidation of methane. Introducing water steam into feedstock can improve the catalytic properties of SrTi1- xMgxO3- δ perovskite type catalysts for OCM reaction at lower temperature. The SrTi0.9Mg0.1O3- δ catalyst has the methane conversion of 28.0 % with C2 hydrocarbons selectivity of 36.8 % under reaction temperature of 550 ℃ .展开更多
The structure and catalytic properties of SrTi0.9M0.1O3- δ (M=Mg,Al, Zr) perovskite type catalysts for oxidative coupling of methane (OCM) have been studied by using X ray diffraction (XRD),X ray photoelectron spectr...The structure and catalytic properties of SrTi0.9M0.1O3- δ (M=Mg,Al, Zr) perovskite type catalysts for oxidative coupling of methane (OCM) have been studied by using X ray diffraction (XRD),X ray photoelectron spectroscopy (XPS) and temperature programmed desorption of oxygen(O2 TPD) methods. It has been shown that doping the cations of lower valence (e.g. Mg2+ , Al3+ ) to the B site of SrTi0.9M0.1O3- δ perovskite type catalysts results in the higher content of adsorbed oxygen species on the surface of catalysts and thus higher C2 selectivity for OCM reaction. It is suggested that the oxygen vacancies of SrTi0.9M0.1O3- δ (M=Mg, Al, Zr) perovskite type catalysts are the sites responsible for oxygen activation, and the adsorbed oxygen species on the surface of SrTi0.9M0.1O3- δ catalysts are the main active species for OCM reaction.展开更多
常压下,采用内循环无梯度反应器在160～200℃温度范围内考察了钙钛矿型复合氧化物催化剂 Lao_(0.4)Sr_(0.6)Mn_(0.6)Co_(0.4)O_3上一氧化碳氧化动力学.实验数据经多元线性加权最小二乘法拟合.其结果为一氧化碳氧化速率对 CO 和氧分压分...常压下,采用内循环无梯度反应器在160～200℃温度范围内考察了钙钛矿型复合氧化物催化剂 Lao_(0.4)Sr_(0.6)Mn_(0.6)Co_(0.4)O_3上一氧化碳氧化动力学.实验数据经多元线性加权最小二乘法拟合.其结果为一氧化碳氧化速率对 CO 和氧分压分别呈0.49级和0.48级的动力学行为.反应的表观活化能为64.0 kJ/mol.并根据动力学行为讨论了该催化剂上 CO 氧化的可能机理.展开更多
文摘The structure and catalytic properties of SrTiO3 perovskite-type oxide catalysts for oxidative coupling of methane (OCM) have been studied by using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and microreactor tests. It has been shown that OCM catalytic properties of SrTiO3 catalysts are correlated to the Sr/Ti atomic ratio. Increasing Sr/Ti ratio in the perovskite?-type SrTiO3 catalysts results in the surface enrichment of Sr element, leading to the the higher content of adsorbed oxygen species on the surface of catalysts and thus higher C2 selectivity for OCM reaction.
文摘The structure and catalytic properties of SrTi1- xMgxO3- δ perovskite type catalysts for oxidative coupling of methane (OCM) have been studied by using X ray diffraction (XRD), X ray photoelectron spectroscopy (XPS) and Temperature programmed desorption (O2 TPD) methods. It has been shown that doping Mg2+ cations to the B site of SrTi1- xMgxO3- δ perovskite type catalysts results in the formation of oxygen vacancies in the lattices of oxide catalysts. With increasing the amount of Mg2+ doped in the B site of SrTi1- xMgxO3- δ , methane conversion and C2 selectivity first increase and then decrease remarkably. The SrTi1- xMgxO3- δ catalyst with x=0.1 has the highest methane conversion and C2 yield. It is suggested that the oxygen vacancies produced by Mg2+ cations doping are the sites responsible for oxygen activation, and the adsorbed oxygen species on the surface of SrTi1- xMgxO3- δ catalysts are the main active species for OCM reaction. However, the over high content of the adsorbed oxygen species on the surface results in the complete oxidation of methane. Introducing water steam into feedstock can improve the catalytic properties of SrTi1- xMgxO3- δ perovskite type catalysts for OCM reaction at lower temperature. The SrTi0.9Mg0.1O3- δ catalyst has the methane conversion of 28.0 % with C2 hydrocarbons selectivity of 36.8 % under reaction temperature of 550 ℃ .
文摘The structure and catalytic properties of SrTi0.9M0.1O3- δ (M=Mg,Al, Zr) perovskite type catalysts for oxidative coupling of methane (OCM) have been studied by using X ray diffraction (XRD),X ray photoelectron spectroscopy (XPS) and temperature programmed desorption of oxygen(O2 TPD) methods. It has been shown that doping the cations of lower valence (e.g. Mg2+ , Al3+ ) to the B site of SrTi0.9M0.1O3- δ perovskite type catalysts results in the higher content of adsorbed oxygen species on the surface of catalysts and thus higher C2 selectivity for OCM reaction. It is suggested that the oxygen vacancies of SrTi0.9M0.1O3- δ (M=Mg, Al, Zr) perovskite type catalysts are the sites responsible for oxygen activation, and the adsorbed oxygen species on the surface of SrTi0.9M0.1O3- δ catalysts are the main active species for OCM reaction.
文摘常压下,采用内循环无梯度反应器在160～200℃温度范围内考察了钙钛矿型复合氧化物催化剂 Lao_(0.4)Sr_(0.6)Mn_(0.6)Co_(0.4)O_3上一氧化碳氧化动力学.实验数据经多元线性加权最小二乘法拟合.其结果为一氧化碳氧化速率对 CO 和氧分压分别呈0.49级和0.48级的动力学行为.反应的表观活化能为64.0 kJ/mol.并根据动力学行为讨论了该催化剂上 CO 氧化的可能机理.
