Crystal-Plane-Dependent Fischer–Tropsch Performance of Cobalt Catalysts

Abstract

Identification of the crystal plane effect of the Co derived from Co3O4 nanocrystals (NCs) on Fischer–Tropsch synthesis (FTS) is important for developing high-performance FTS solid catalysts. However, the achievement of this goal is hindered by the complexity of the FTS and the absence of sufficient crystallographic structure data. In this study, we report that the experimental FT performance of the Co catalysts depends on the exposed crystal facets of the Co3O4 NCs. The exposed Co3O4 NC {112} facets have the highest catalytic activity and the lowest methane selectivity (6.2%) in comparison to those of the {111} and {001} planes. The evolution of the crystal planes during the reduction was investigated further, and the preferred orientation relationship induced by the Co3O4 → Co transformation was {112} → {10–11}, {111} → {0001}, and {001} → {11–20}. CO temperature-programmed surface reaction experiments and density functional theory calculations further verified that the high FT performance of Co3O4{112}...