Carbon Coated Supports for Cobalt Based Fischer-Tropsch Catalysts

Cobalt based Fischer-Tropsch synthesis catalysts were prepared on carbon coated alumina supports. Carbon coating resulted in a decrease in the average cobalt crystallite size (down to 6 nm) and increased active cobalt metal surface area. Very importantly, the use of carbon on the alumina surface also altered the cobalt nitrate mechanism of binding and thermal decomposition, resulting in a significant change in the macroscopic cobalt distribution with improved inter-particle distances. The enhanced cobalt metal surface areas together with the significantly improved cobalt distribution/inter-particle distances resulted in cobalt Fischer-Tropsch synthesis catalysts with an activity that was increased by 40-75 % without having a negative influence on the methane selectivity.