Facile synthesis of a highly efficient Co/Cu@NC catalyst for base-free oxidation of alcohols to esters

Abstract

The direct oxidation of alcohols to esters is an environmentally benign and cost-effective organic synthetic strategy, but it is still a great challenge to discover an economic, highly active, and long-term stable catalyst for efficient transformation of alcohols to esters under milder conditions. Herein, we developed cobalt and copper nanoparticle -co-decorated nitrogen-doped carbon catalysts (CoCu@NC_n) through two steps of ball milling and calcination. It was found that CoCu@NC_n could catalyze the oxidation of alcohols to esters effectively in the absence of basic additives. The catalytic activity was much higher than those of monometallic Co@NC₂ and Cu@NC₂ samples, and the catalyst can be conveniently recovered and quite steadily reused. Through a series of control experiments and characterizations, it is concluded that the remarkable catalytic performance of CoCu@NC₂ was associated with the synergistic effect between the two metal components, the enhanced basic active sites and the active surface area.