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采用溶胶凝胶法制备了Sr/Ti摩尔比为1.2的纳米钙钛矿型复合氧化物SrTiO3催化剂,比较了纳米SrTiO3催化剂和相同组成的常规SrTiO3催化剂对甲烷氧化偶联(OCM)反应的催化性能,并采用XRD,TEM和原位ESR技术对催化剂进行了表征.结果表明,纳米SrTiO3催化剂具有较好的低温催化OCM反应性能.在反应气氛下催化剂表面形成的吸附氧物种和F中心能够活化甲烷生成C2烃,但吸附氧物种最终导致反应中间体和C2烃完全氧化;F中心则能在低温下活化甲烷,并高选择性地生成C2烃.纳米SrTiO3催化剂不仅含有吸附氧物种,而且含有高浓度的F中心,而常规SrTiO3催化剂上只有吸附氧物种.
A nano-perovskite-type composite oxide SrTiO3 with Sr / Ti molar ratio of 1.2 was prepared by sol-gel method. The catalytic performance of the nano SrTiO3 catalyst and the conventional SrTiO3 catalyst with the same composition on the oxidative coupling of methane (OCM) , And the catalysts were characterized by XRD, TEM and in-situ ESR.The results show that the nanostructured SrTiO3 catalyst has good low-temperature catalytic properties for OCM reaction.The adsorbed oxygen species and F center formed on the catalyst surface in the reaction atmosphere can activate methane But the oxygen species eventually lead to the complete oxidation of the reaction intermediates and C2 hydrocarbons.The F center can activate methane at low temperature and generate C2 hydrocarbons with high selectivity.The nano SrTiO3 catalyst not only contains the adsorbed oxygen species but also contains high Concentration of F center, while the conventional SrTiO3 catalyst only adsorbed oxygen species.