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用自燃烧法制备了钙钛矿型La0 8Sr0 2 FeO3 催化剂 .用H2 TPR考察了催化剂表面的氧消耗过程 ,用程序升温表面反应(TPSR)研究了甲烷与催化剂表面氧物种的反应 ,用在线质谱脉冲反应和甲烷 /氧切换反应研究了催化剂的晶格氧选择氧化甲烷制合成气 .结果表明 ,催化剂上存在两种氧物种 ,无气相氧存在时 ,强氧化性氧物种首先将甲烷氧化为CO2 和H2 O ;而后提供的氧化性较弱的晶格氧具有良好的甲烷部分氧化选择性 ,可将甲烷氧化为合成气CO和H2 (选择性可达 95 %以上 ) .在 90 0℃下的CH4/O2 切换反应结果表明 ,甲烷能与La0 8Sr0 2 FeO3 中的晶格氧反应选择性地生成CO和H2 ,失去晶格氧的La0 8 Sr0 2 FeO3 能与气相氧反应恢复其晶格氧 .在合适的反应条件下 ,用La0 8Sr0 2 FeO3 催化剂的晶格氧代替分子氧按Redox模式实现甲烷选择氧化制合成气是可能的 .
The perovskite-type La0 8Sr0 2 FeO3 catalyst was prepared by self-combustion method. The oxygen consumption of the catalyst surface was investigated by H2 TPR. The reaction of methane with oxygen species on the catalyst surface was investigated by temperature programmed surface reaction (TPSR) Pulse reaction and methane / oxygen shift reaction were used to study the lattice oxygen selective oxidation of methane to syngas.The results showed that there were two kinds of oxygen species on the catalyst. In the absence of gas phase oxygen, the strongly oxidizing oxygen species first oxidized methane to CO2 And H 2 O; and the subsequently provided less oxidative lattice oxygen has good partial oxidation selectivity for methane, which can be oxidized to syngas CO and H 2 (with a selectivity up to 95%). At 90 ° C The CH4 / O2 switching reaction results show that methane can react with lattice oxygen in La0 8Sr0 2 FeO3 selectively to form CO and H2, and La0 8 Sr0 2 FeO3, which lacks lattice oxygen, can react with vapor oxygen to restore its lattice oxygen. Under appropriate reaction conditions, the selective oxygenation of methane to syngas is possible by substituting lattice oxygen of La0 8Sr0 2 FeO3 for molecular oxygen in the Redox mode.