Methanation of Carbon Dioxide over a Highly Dispersed Ni/La2O3 Catalyst

The methanation of carbon dioxide on a Ni/La2O3 catalyst containing 10 wt% Ni prepared by the impregnation method was studied. The space-time yield of methane was 3000 g/(kg·h) at conditions of 350 °C, GHSV of 30000 h−1, 1.5 MPa pressure, and H2/CO2 molar ratio of 4. The selectivity for methane was 100% with different CO2 conversions. Combined with X-ray diffraction and H2 temperature-programmed reduction analyses, this suggested that the reaction mechanism on Ni/La2O3 may be different from that on Ni/γ-Al2O3. The formation of lanthanum oxycarbonate (La2O2CO3) can play an important role in the activation of CO2. 以䜕La2O3䜕为载体,䜕采用浸渍法制备了䜕10%Ni/La2O3䜕催化剂,䜕考察了该催化剂的䜕CO2䜕甲烷化反应性能.䜕䜕结果表明,䜕在较低的温度䜕(350䜕°C)䜕和高空速䜕(约䜕30000䜕h–1)䜕下,䜕甲烷时空收率可大于䜕3000䜕g/(kg·h),䜕无论转化率高低,䜕甲烷选择性始终保持在䜕100%.䜕䜕X䜕射线衍射和䜕H2-程序升温还原等表征结果表明,䜕CO2䜕在䜕Ni/La2O3䜕催化剂上的加氢机理可能与䜕Ni/γ-Al2O3䜕上不同,䜕并且䜕La2O2CO3䜕的形成有利于提高催化剂活性. 关键词二氧化碳;䜕䜕甲烷化;䜕䜕镍;䜕䜕氧化镧;䜕䜕负载型催化剂;䜕䜕氧化碳酸镧