锆改性钴基费-托合成催化剂催化性能的研究

 考察了助剂锆和金属钴负载量对锆改性Co／Al2O3催化剂催化性能的影响．结果表明，锆助剂能够高度分散在氧化铝载体上，而活性组分钴以一定尺寸存在；锆的添加能够明显地提高Co／Al2O3催化剂的催化活性和C5＋烃选择性，但助剂锆含量对催化剂催化性能的影响不大；在锆存在下，催化剂的催化活性随金属钴含量先升高后降低．进一步的研究表明，催化剂上烃形成速率的提高可能是由于锆助剂能够增加催化剂的活性位数目，增强桥式CO吸附的强度，在Co－ZrO2间形成界面．

Influence of Zirconia Promoter on Catalytic Performance of Cobalt Catalysts for Fischer-Tropsch Synthesis

Two series of ZrO 2 promoted Co/Al 2O 3 catalysts were prepared by incipient wetness impregnation method to investigate the effects of zirconia and cobalt loadings on the structure and catalytic performance of cobalt catalysts for Fischer Tropsch synthesis. It was found that the addition of ZrO 2 promoter can distinctly improve CO conversion and C 5+ hydrocarbon selectivity, and the loading of ZrO 2 promoter seems to have no influence on the catalytic performance of CoZr/Al 2O 3 catalysts. For the cobalt based catalysts containing 15%Zr promoter, the catalytic activity firstly enhances and then decreases with increasing loading of metallic cobalt. When the zirconia loading increased from 0% to 20%, the highly dispersed zirconia existed on the surface of support, and however, the cobalt oxides agglomerated in a certain size. The addition of ZrO 2 promoter can increase the amounts of active sites and then result in the formation of interfaces between metallic cobalt and ZrO 2 promoter, which promotes the appearance of more CO adsorbed in bridged mode, and that the CoZr/Al 2O 3 catalysts are more active than the Co/Al 2O 3 catalyst.