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
用柠檬酸络合法制备了钙钛矿型 La Fe O3及 La Fe1 - x Cux O3化合物 ,测定了其对酸性红 3B等水溶性染料的光催化降解活性 .利用红外、紫外和光声光谱、正电子寿命谱及光电子能谱等技术分析了 La Fe O3的光催化性能及掺杂对其活性的影...用柠檬酸络合法制备了钙钛矿型 La Fe O3及 La Fe1 - x Cux O3化合物 ,测定了其对酸性红 3B等水溶性染料的光催化降解活性 .利用红外、紫外和光声光谱、正电子寿命谱及光电子能谱等技术分析了 La Fe O3的光催化性能及掺杂对其活性的影响 .结果表明 ,掺杂 Cu2 + 可使 La Fe展开更多
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.
文摘用柠檬酸络合法制备了钙钛矿型 La Fe O3及 La Fe1 - x Cux O3化合物 ,测定了其对酸性红 3B等水溶性染料的光催化降解活性 .利用红外、紫外和光声光谱、正电子寿命谱及光电子能谱等技术分析了 La Fe O3的光催化性能及掺杂对其活性的影响 .结果表明 ,掺杂 Cu2 + 可使 La Fe
