Electrochemical glucose-to-formic acid conversion coupled with alkaline hydrogen production over nanostructured CuCo2O4 catalysts

Abstract

Coupling the hydrogen evolution reaction (HER) with the electrochemical oxidation of glucose (GOR), which is one of the most abundant biomass-based platform molecules, could be a promising approach to reduce energy consumption of hydrogen production and meanwhile produce the value-added chemicals powered by renewable energy. However, GOR remains difficult to develop an efficient electrocatalyst with high-activity and low-cost. Herein, we introduce a serious of earth-abundant elements into Co3O4 spinel nanostructure as electrocatalysts for GOR. The optimized CuCo2O4 spinel oxide nanoneedle exhibits excellent GOR electrocatalytic activity, which only requires 1.31/1.40 V vs reversible hydrogen electrode (RHE) to achieve the high current densities of 200/500 mA cm−2 and obtains a high 98% faraday efficiency of formate at 1.40 V vs RHE. The high performance is attributed to the abundant oxygen vacancies and transient formation of CoOOH active species on the surface of CuCo2O4 and rapid consumption by the spontaneous chemical reaction with glucose, which are evidenced by in-situ Raman spectroscopic measurements and electrochemical tests. The two-electrode electrolytic cell voltage of GOR coupled with HER is about 370 mV lower than that of the overall water electrolysis at 200 mA cm-2.