Effect of support and its surface modifications in cobalt-based Fischer-Tropsch synthesis

Overview & Synopsis

Support effects in heterogeneous catalysis are evolving as an important field of investigation to optimize catalyst properties. The cobalt-based Fischer-Tropsch (FT) catalysts usually consist of metallic cobalt nanocrystallites dispersed on a support material. The present article attempts to survey the progress that has been made over the last couple of decades in the area of support and its surface modification effects in cobalt-based FT synthesis. Different catalyst supports such as alumina, silica, titania, niobia, zirconia, zeolite, ceria, carbon-based materials, silicon carbide, aluminum phosphate, hydrotalcite, metal-organic frameworks, and metal foams are discussed and compared with classical supports like alumina or silica wherever it permits. The properties such as metal-support interaction, support induced size and morphology of cobalt nanocrystallites (textural properties of the support), change in electronic properties of the cobalt clusters, and acid-base nature of the support are examined, and wherever possible the activity and/or selectivity in FT synthesis were discussed. This review also summarizes findings of new and promising supports for FT catalysts. A guidance for support modifications and support choice as a function of the product selectivity in FT process was also proposed.