Study on the effect of alkali promoters on the formation of cobalt carbide (Co2C) and on the performance of Co2C via CO hydrogenation reaction

Abstract

The present investigation deals with an alkali metal assisted synthesis of cobalt carbide (Co2C), starting from carburizing reduced complex precursors (obtained from Co3O4 with the addition of Li2O, Na2O and K2O) using CO as a carburization source. It is found that the Co2C formation could be significantly accelerated by the Li component. A comparative study reveals that the promotion effect of Li component may be related to the H2 adsorption on the reduced precursor, which enhanced the ability of the precursor to react with CO. Furthermore, the Co2C prepared from the precursor containing Li component shows a considerable increase in activity for CO hydrogenation and an improved fraction of higher alcohols in the total alcohol products, compared to the Co2C prepared without promoters. An attempt is made to elucidate the catalytic behavior of the as-prepared Co2C samples.