Rational design of tungsten-doped cobalt molybdate nanosheet arrays for highly active ethanol-assisted hydrogen production

Abstract

Ethanol oxidation reaction (EOR) is a promising substituent to the conventional oxygen evolution reaction (OER) for highly active and energy-saving hydrogen production. The rational design of bifunctional electrocatalysts to achieve ethanol-assisted water splitting is important, but still maintains challenge. Herein, we successfully synthesize a tungsten (W) doped cobalt molybdate nanosheet arrays on porous copper foam by one-step hydrothermal method (W–CoMoO4/CF). The synthesized W–CoMoO4/CF shows the morphology of neatly stacked cobblestone nanosheets with high surface area and improved reaction kinetics, leading to substantial bifunctional catalytic activity for EOR/hydrogen evolution reactions (HER). To reach a current density of 100 mA cm−2, only an overpotential of 102 mV is demanded when using W–CoMoO4/CF as an electrode for HER, while a potential of 1.40 V is required for EOR. Moreover, the ethanol-assisted water electrolyzer is constructed by using W–CoMoO4/CF as both anode/cathode, which requires a small total voltage of 1.54 V to achieve 100 mA cm−2 and could run steadily for 12 h, revealing its excellent application prospects. This study provides a promising guidance for the development of high-valence metal modified bimetallic oxides for hydrogen generation.