助剂对Ni基催化剂结构及甲烷化性能的影响

本文采用等体积浸渍制备了掺杂不同金属助剂改性的Ni基催化剂,考察了其催化浆态床CO甲烷化的性能。通过XRD、H2-TPR、HR-TEM等表征对催化剂进行了分析,结果表明,掺杂Zr、Co、Ce、Zn、La助剂促进了Ni物种在载体表面的分散,减小了Ni的晶粒尺寸,降低了催化剂的还原温度;掺杂Mg助剂则导致催化剂的还原温度升高。浆态床活性评价结果表明,掺杂Zr、Co、Ce、Zn、La助剂提高了催化剂的甲烷化性能,其中以La助剂的效果最明显,通过对La负载量进一步优化后发现,当La负载量为8%时,催化剂的甲烷化催化性能最优,CO转化率、CH4选择性和时空收率分别达到96.3%、87.1%和179.6 g·kg-1·h-1;掺杂Mg助剂则降低了催化剂的甲烷化活性。

Effects of Additives on Sturcture and Methanation Performance of Ni-Based Catalysts

Nickel-based catalysts were prepared with different metal promoters by incipient impregnation method, and the catalytic performance of CO methanation were studied in slurry-bed reactor. XRD, H₂-TPR, and HR-TEM were used to characterize the catalysts, the results show that additives of Zr, Co, Ce, Zn, La improved the dispersion of Nickel species on support, and decreased the particle size of Ni and reduced the reduction temperature of catalyst, while the additive of Mg increased the reduction temperature. The catalytic results show that additives of Zr, Co, Ce, Zn, La improved the catalytic performance of CO methanation in slurry-bed reactor, especially the catalyst with La additive. Further investigation shows that when the loading of La reached 8%, the catalyst exhibited the best catalytic performance, with the conversion of CO of 96.3%, the selectivity and space-time yield (STY) of CH₄ of 87.1% and 179.6 g·kg^-1·h^-1, respectively. While the catalyst doped with Mg additivie decreased the catalytic performance.