Crystal facet dependence of carbon chain growth mechanism over the Hcp and Fcc Co catalysts in the Fischer-Tropsch synthesis

Abstract

Revealing the sensitivity of Co crystal facet structure to the mechanism of carbon chain growth in the Fischer-Tropsch synthesis (FTS) is of great importance yet challenging issue in the heterogeneous catalysis. According to the occupied proportion of different crystal facets in the hcp and fcc Co crystal phases, this study for the first time identifies the essential relationship between the performance of carbon chain growth in the FTS and the structure of Co crystal facets. The hcp Co generally presents much higher intrinsic activity for the carbon chain growth via the carbide mechanism compared to the fcc Co via the CHO insertion mechanism. The findings will deepen our understandings about the crystal facet structure-dependent performances of Co catalysts in the FTS reactions, and provides a clear clue for the preparation of high performance Co catalysts through the rational design of Co crystal facet with more stepped B5-type active unit.