摘要
本文以瞬变应答法研究了CO_2在镍催化剂上甲烷化反应过程的机理。通过对响应曲线的分析指出H_2和CO_2在催化剂活性中心上发生竞争吸附。CO_2的甲烷化存在着两条平行路径,一是解离吸附的H_2与气相CO_2反应生成CO,再进一步加氢生成CH_4;另一路径是吸附的H_2和吸附的CO_2发生反应,生成中间化合物,进一步加氢生成CH_4,它不经由生成CO。这两步平行的基元反应也是总反应的控制步骤。
The mechanism of methanation of carbon dioxide over Ni catalyst has been studied by applying a transient response method at temperature ranging from 350 to 400℃. The analysis of response curves showed that there are competing adsorption between hydrogen and carbon dioxide on the active sites of catalyst. There are two parallel mechanisms in methanation of carbon dioxide. The one is that dissociated adsorbed hydrogen reacts with carbon dioxide in gas phase to produce carbon monoxide which is hydrogenated further to form methane. The other is adsorbed hydrogen reacts with adsorbed carbon dioxide to form an intermediate which is methanized without passing through formation of carbon monoxide. Both are the slower steps in the overall reaction.
基金
国家自然科学基金
关键词
CO2
甲烷化
镍催化剂
瞬变应答
reaction
mechanism
transient response
Ni catalyst
methanation
