Moderate Surface Segregation Promotes Selective Ethanol Production in CO2 Hydrogenation Reaction over CoCu Catalysts.

Abstract

Cobalt-copper (CoCu) catalyst is known to have potential industrial application to catalyze CO/CO 2 hydrogenation reactions. And CoCu alloy has been elucidated as major active phase during reactions. However, due to the elemental surface segregation and even dealloying phenomena, the actual surface morphology of CoCu alloy is still unclear. Herein, combining theory and experiment, this paper describes the dual effect of surface segregation and varied CO coverage over CoCu(111) surface on the reactivity in CO 2 hydrogenation reactions. The wrestling relation between C-O bond scission and further hydrogenation of intermediate *CH 2 O was discovered as the key step to promote ethanol production. The theoretical investigation suggests that moderate Co segregation provides a suitable surface Co ensemble with lateral interactions of co-adsorbed *CO, leading to promoted selectivity to ethanol, in agreement with theory-inspired experiments.