On the origin of the cobalt particle size effects in Fischer−Tropsch catalysis

Abstract

The effects of metal particle size in catalysis are of prime scientific and industrial importance and call for a better understanding. In this paper the origin of the cobalt particle size effects in Fischer−Tropsch (FT) catalysis was studied. Steady-State Isotopic Transient Kinetic Analysis (SSITKA) was applied to provide surface residence times and coverages of reaction intermediates as a function of Co particle size (2.6−16 nm). For carbon nanofiber supported cobalt catalysts at 210 °C and H2/CO = 10 v/v, it appeared that the surface residence times of reversibly bonded CHx and OHx intermediates increased, whereas that of CO decreased for small (