Low-dimensional Mo:BiVO4 photoanodes for enhanced photoelectrochemical activity

Abstract

Vertically oriented pure BiVO₄ and Mo-doped BiVO₄ nanoworm array films with a diameter of about 100 nm were prepared using the pulsed laser deposition (PLD) technique. Photoanodes doped with 1% molybdenum at vanadium sites provided superior photocurrent density, up to 2.1 mA cm⁻² and 1.7 mA cm⁻² at 1.23 V vs. the reversible hydrogen electrode (RHE) with Na₂SO₃ as the hole scavenger for substrate to electrode illumination and electrolyte to electrode illumination, respectively. The improved photoelectrochemical (PEC) performance of 1% Mo:BiVO₄ photoanodes primarily originated from an appropriately regulated composition and a desirably controlled porous morphology. The outstanding PEC performance highlights the significance of a vertically oriented nanoworm array nanoarchitecture with a large surface area as a promising photoanode that ensures enhanced light absorption without sacrificing effective charge collection. This study is expected to enable BiVO₄ to be applied as an efficient photoanode in PEC water splitting processes and to open the door to the large-scale manufacture of metal oxide photoanodes using the PLD technique for highly efficient photochemical performance.