超细CuO/ZnO/SiO_2催化剂上CO_2和CO加氢反应对比──CO_2加氢反应机理

COMPARISON OF HYDROGENATION OF CO 2 AND CO OVER ULTRAFINE CuO/ZnO/SiO 2 CATALYSTS REACTION MECHANISM OF HYDROGENATION OF CO 2

在超细ＣｕＯ／ＺｎＯ／ＳｉＯ２催化剂体系上，对比研究了ＣＯ２和ＣＯ加氢性能，并就ＣＯ２加氢的反应机理进行了探讨。考察了接触时间和反应压力对ＣＯ２加氢的主要产物甲醇和ＣＯ分布的影响。结果表明，ＣＯ２加氢生成甲醇和ＣＯ是平行反应，生成的甲醇直接来源于ＣＯ２本身，没有经历ＣＯ中间物种，而且生成的ＣＯ能够适当地进一步加氢生成甲醇。在超细ＣｕＯ／ＺｎＯ／ＳｉＯ２催化剂体系的ＣＯ加氢反应主要产物是二甲醚和甲醇，这进一步支持上述反应机理。在４８８～５６８Ｋ反应温度范围内，超细ＣｕＯ／ＺｎＯ／ＳｉＯ２催化剂对ＣＯ２加氢的催化活性高于对ＣＯ加氢的活性。

The hydrogenation of both CO 2 and CO were carried out on the ultrafine CuO/ZnO/SiO 2 catalysts prepared by solgel method and the reaction mechanism of hydrogenation of CO 2 was discussed The effects of contact time and reaction pressure from 1 0￣4 0MPa on the product distribution of CO 2 hydrogenation were investigated to clarify the reaction mechanism The main products of hydrogenation of CO 2 were methanol and CO, while dimethyl ether and methanol were the main products of hydrogenation of CO Our studies confirmed that the methanol from hydrogenation of CO 2 came directly from CO 2 rather than from CO, and the formation of methanol and CO from CO 2 were parallel reactions, moreover a suitable amount of CO formed from CO 2 could turn into methanol The comparative result of hydrogenation of CO further supported above mechanism and the ultrafine CuO/ZnO/SiO 2 catalysts showed higher activity to hydrogenation of CO 2 than to hydrogenation of CO in 488568K