Al_2O_3负载镍基催化剂上CO_2氢甲烷化研究

Methanation of Carbon Dioxide by Hydrogenating over Ni Supported on Al_2O_3 Catalysts

通过对 Ni/Al2 O3及添加 Ce O2 的 Ni/Al2 O3催化剂上 CO2 氢甲烷化反应的研究发现 ,在反应过程中 ,该体系的催化剂上并不产生 CO,添加 Ce O2 后能显著提高甲烷产率 .原位漫反射红外光谱研究发现 ,甲烷可通过表面 CO- 2 物种加氢或表面甲酸盐加氢两种途径产生 ,且第二种途径更有效 ;添加 Ce O2 可通过在较低温度时形成较多的表面甲酸盐来提高 CO2

Methanation of carbon dioxide by hydrogenating over Ni/Al\-2O\-3 and Ni\|CeO\-2/Al\-2O\-3 catalysts was investigated by methods of reaction and \%in\|situ \%diffuse reflectance FTIR(\%in\|situ\% DRFTIR). The results showed that carbon monooxide was not the product over those catalysts whether CeO\-2 was added or not, but the yield of methane was increased with CeO\-2 addition. At 300 ℃, the yield of methane over \{Ni\|CeO\-2/\}Al\-2O\-3 catalysts was two times higher than that over Ni/Al\-2O\-3 catalysts. The DRFTIR results showed that methane came from two processes, which were hydrogenation of CO\+-\-2 species and formate species over the catalysts. The more effective species was formate on the surface of catalyst. The reason why the activity of Ni/Al\-2O\-3 catalyst was promoted by addition CeO\-2 was that a large amount of formate forms over Ni\|CeO\-2/Al\-2O\-3 catalyst.