Spinel-oxide-integrated BiVO₄ photoanodes with photothermal effect for efficient solar water oxidation

Abstract

Spinel oxide materials have been widely used as oxygen evolution catalysts to enhance the photoelectrochemical (PEC) performance of photoelectrodes. Herein, we demonstrate that the water splitting efficiency of a photoanode can be further enhanced by introducing its photothermal effect. Under near-infrared radiation, the temperature of the NiCo2O4/BiVO4 photoanode increases moderately, leading to improved water oxidation kinetics and charge transport simultaneously. With the assistance of the photothermal effect, the obtained photoanode reaches a photocurrent density of 6.20 mA cm-2 at 1.23 V vs reversible hydrogen electrode. A series of spinel-type MCo2O4 oxides (M = Mn, Zn, Cu, and Fe) are deposited on the surface of the BiVO4 photoanode to show similar photothermally enhanced PEC performance. The research discovery provides a way for improving the catalytic activity of photoanode materials with a photothermal effect, which may be applied to various fields of energy conversion, including CO2 reduction, N2 fixation, and pollutant degradation.