Preparation of Highly Dispersed Nb2O5 Supported Cobalt-Based Catalysts for the Fischer-Tropsch Synthesis

In this work, niobia supported cobalt catalysts with both high cobalt dispersion and high cobalt loading (15 wt %) were prepared through the assistance of glow discharge plasma treatment, and their catalytic performance was tested in Fischer-Tropsch synthesis (FTS). Plasma treatment on support and especially on the decomposition of the catalyst precursor leads to a noticeable enhancement of cobalt dispersion. However, in addition to the cobalt dispersion improvement, plasma assisted decomposition of the cobalt precursor also led to the formation of CoNb2O5, which was inactive in FTS; moreover, the small cobalt particles underwent severe sintering during the reaction and caused significant and contineous deactivation. Plasma treatment on nobia could modify its porosity and hydrophilicity and generate surface functional groups; these features enabled an improved cobalt-niobia interaction and better cobalt dispersion on CoN(P)-C than on CoN-C. The enhanced FTS activity and best reaction stability on the CoN(P)-C catalyst were due to the possession of a suitable cobalt particle size and moderate cobalt-niobia interaction.