Development of Oxidation Reactor Using Solid Electrolyte Cell with Catalytic Electrode of Perovskite-type oxide

将固体电解质氧化反应器应用于甲烷的氧化偶联反应。本次调查的结果如下：1。通过固体电解质的氧离子比从气相吸附的氧离子在Ag催化剂电极上的反应性更强。在Ag电极上，C_2化合物在输运体系中形成的速率是在预混体系中形成速率的10倍。用于氧化偶联的氧的比例相当小，并且强烈依赖于电极材料。在LaCoO_3电极上，主要进行完全氧化，少量未反应氧。这些结果表明，参与氧化偶联反应的氧活性物质与在固体电解质中扩散的氧离子O^<2->不同。以碱土金属Ca、Sr、Ba和过渡金属Ti、Zr、Ce为原料制备的钙钛矿型氧化物在氧化偶联反应中具有较高的催化活性。这些复合氧化物非常稳定，而碱土金属的单一氧化物在此反应中变成碳酸盐。5 . a位离子在该反应中起了重要作用，这与先前发现的b位离子起作用相反。发现氧化物单位表面积的催化活性与氧离子与金属离子之间距离的位移之间有明显的相关性。

A solid electrolyte oxidation reactor has been applied to the oxidative coupling reaction of methane. Findings from this investigation are as follows:1.The oxygen ion passing through the solid electrolyte was more reactive over Ag catalyst electrode than the adsorbed oxygen from the gas phase. Over Ag electrode, C_2 compounds were formed at the rate of about ten times larger in the transport system than in the premixture system.2.The fraction of oxygen utilized to the oxidative coupling was rather small and strongly dependent on the electrode material.3.Over LaCoO_3 electrode, complete oxidation predominantly proceeded with little amount of unreacted wxygen. These results suggested that the oxygen active species participating the oxidative coupling reaction are different from the oxygen ions, O^<2->, diffusing through the solid electrolyte.4.Many of the perovskite-type oxides made from such an alkaline earth metal as Ca, Sr, Ba and a transition metal, Ti, Zr, or Ce had high catalytic activity in oxidative coupling reaction. These complex oxides were very stable whereas the single oxide of alkaline earth metal changed to carbonate in this reaction.5. The A-site ion played an important role in this reaction in contrary to the previous finding that the B-site ion did.6.A clear correlation was found between the catalytic activity per unit surface area of oxide and the displacement of the distance between an oxygen ion and a metal ion.