Fischer-Tropsch synthesis using zeolitic imidazolate framework (ZIF-7 and ZIF-8)-supported cobalt catalysts

The Fischer-Tropsch synthesis using cobalt catalysts supported on zeolitic imidazolate frameworks (ZIFs), ZIF-7 and ZIF-8, has been investigated. ZIF-7, ZIF-8 and corresponding cobalt-containing catalysts, after preparation, were characterized using various techniques. Thermogravimetric analysis results show that ZIF-7 and ZIF-8 supports have good thermal stability for the Fischer-Tropsch synthesis reaction, and weaker interaction between cobalt and zinc in the ZIF-7 and ZIF-8 supports results in more cobalt reduction. The catalytic performance was evaluated in Fischer-Tropsch synthesis and compared with that of a cobalt catalyst supported on SBA-15 promoted with zinc. The pore structure of the ZIF supports plays an essential role in product selectivity for the prepared catalysts. The carbon number in hydrocarbon products and olefin selectivity depend on cobalt dispersion and support structure owing to the impacts of site density and carrier skeleton on the speed of diffusion-enhanced olefin re-adsorption reactions.