In this work, a series of SiO₂ supported Co catalyst have been prepared by adding urea or ruthenium to the cobalt precursor solution compared with the catalysts prepared without using urea. The characterization results show that cobalt is present as Co₃O₄ over the silica supports. The addition of urea to the catalyst precursor helps to generate smaller crystallite even at very high cobalt loading, while impregnation without using urea results in larger crystallite size as Co loading increases. Likewise, the addition of Ru to the catalyst precursor leads to a more uniform crystallite of Co₃O₄, and can help to lower the Co₃O₄ crystallite size to some extent, which has the similar effect on the catalyst prepared with urea. We have also shown that the support pore size and volume do have significant effect on the crystallite size of the cobalt oxide. The catalytic performances of the Co/SiO₂ catalysts prepared with and without adding urea have been evaluated for Fischer Tropsch synthesis and the catalyst prepared using urea demonstrates significantly improved catalyst activity as well as selectivity to C₅⁺.

在这项工作中，与不使用尿素制备的催化剂相比，已经通过向钴前体溶液中添加尿素或钌来制备了一系列SiO ₂负载的Co催化剂。表征结果表明，钴以Co ₃ O _4的形式存在于二氧化硅载体上。即使在非常高的钴负载量下，向催化剂前体中添加尿素也有助于生成较小的微晶，而随着钴负载量的增加，不使用尿素的浸渍导致较大的微晶尺寸。同样，将Ru添加到催化剂前体中会导致Co ₃ O _4的晶粒更加均匀，并有助于降低Co ₃ O _4。微晶尺寸，在一定程度上对用尿素制备的催化剂具有相似的作用。我们还表明，载体的孔径和体积确实对氧化钴的微晶尺寸有显着影响。已经针对费-托合成评估了添加和不添加尿素制备的Co / SiO ₂催化剂的催化性能，并且使用尿素制备的催化剂显示出显着改善的催化剂活性以及对C ₅ ^+的选择性。