Comprehensive evaluation of copper vanadate (α-CuV2O6) for use as a photoanode material for photoelectrochemical water splitting

Abstract

This study is an initial account of solution-based spray pyrolysis-produced n-type copper vanadate (CuV2O6) thin film photoanodes. CuV2O6 photoelectrodes have been tested for their ability to oxidize water in aqueous (pH 6.8) solutions using photoelectrochemical (PEC) tests. The band edge positions, band gap energy, photocurrent generation, flat band potential, chemical make-up, chemical stability, charge carrier transit, and O2 production faradic efficiency are a few of the physical and photophysical features measured and described. According to the findings, CuV2O6 possesses a satisfactory bandgap of 1.9 eV and appropriate band locations that allow for the use of visible light for overall solar water splitting. Under AM1.5 simulated sunlight, the maximum photocurrent density recorded is 0.18 mA cm− 2 at 1.23 VRHE with Na2SO3 acting as a hole scavenger. As evidenced by film shape, surface compositions before and after the PEC measurements, and outstanding structural and compositional stability throughout the oxygen evolution reaction (OER), the CuV2O6 photoelectrodes performed well. CuV2O6 photoanodes also exhibit almost a unit faradic efficiency for the oxidation of water. The overall photoelectrochemical efficiency, however, is constrained by the photogenerated charge carriers' weak mobility (∼8 ×10−3 cm2 V−1 s−1), short lifetime (∼20 ns), and limited hole diffusion length (∼20.4 nm), according to time-resolved microwave conductivity (TRMC) tests. Based on the current findings, this study offers new insight into building enhanced high-quality CuV2O6 photoanodes by methodically clarifying numerous important physical and photoelectrochemical characteristics for the photooxidation of water.