Hollow RuV-Co(OH)2 arrays for efficiently electrocatalytic H2 production assisted by glucose oxidation

Abstract

Electrochemical water splitting is a promising method for hydrogen production but is restricted by sluggish oxygen evolution reaction (OER), so we propose to replace OER with the thermodynamically preferred glucose oxidation reaction (GOR) to reduce the supply voltage. Herein, hollow RuV-Co(OH)2 arrays have been fabricated by the hydrothermal method of sacrificing ZIF-67 to codope vanadium (V) and ruthenium (Ru). Electrochemical studies show that RuV-Co(OH)2 has excellent hydrogen evolution reaction (HER) activity with a low overpotential of 77 mV at the current density of 10 mA cm−2 (η10 = 77 mV) and good GOR activity. Density functional theory (DFT) calculations indicate that V and Ru tune the electronic structure of RuV-Co(OH)2, greatly increasing the density of the active sites. Moreover, RuV-Co(OH)2 assembled glucose-assisted hydrogen evolution cell exhibits a battery voltage of 1.42 V for a current density of 10 mA cm−2, a significant reduction of 240 mV compared to overall water splitting along with higher-value glucose oxidation products. Furthermore, RuV-Co(OH)2 exhibits outstanding stability. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) analysis demonstrate that RuV-Co(OH)2 has superior mechanical stability. This work opens up a new approach to designing novel bifunctional electrocatalysts for energy-saving H2 production and valuable coproductions.