Controlled over-growth for nail-like and urchin-like cobalt with enhanced CO hydrogenation activity

Abstract

Cobalt catalysts have great potentials towards CO hydrogenation. Herein, a facial H2 pressure-controlled strategy was developed to synthesize two typical branched cobalt nanostructures: nail-like cobalt and urchin-like cobalt. The H2-controlled over-growth mechanisms have been proposed, and supported by both experiments and DFT calculations. The over-growth of Co nanocrystals can be finely controlled by the selective and competitive adsorption between H2 and OAm molecules on cobalt surface. Both nail-like cobalt and urchin-like cobalt exhibit superior CO hydrogenation activity to ordinary Co nanoparticles, due to their HCP phase, unique branch structure with high specific area, and more exposed active (1 0 −1 1) crystal facets.