Fischer-Tropsch to olefins over Co2C-based catalysts: Effect of thermal pretreatment of SiO2 support

Abstract

SiO2 supported Co2C-based catalysts were used for Fischer-Tropsch to olefins (FTO), and the effect of thermal pretreatment of SiO2 support under different temperatures on the Co2C morphology and catalytic performance was investigated. It was found that the interaction between cobalt and support was weakened when SiO2 was pretreated at high temperature (990 °C) due to the decreased content of surface SiOH groups. The relative weak interaction between cobalt and support benefited the formation of cobalt manganese composite oxide after calcination and reduction, and thus promoted the generation of Co2C nanoprisms with promising FTO performance. In contrast, for the SiO2 support pretreated at 350 °C or 650 °C, the strong interaction between cobalt and support led to phase separation of cobalt and manganese. As a result, only Co2C nanospheres were generated which displayed low activity and high methane selectivity.