Non-noble-metal bismuth nanoparticle-decorated bismuth vanadate nanoarray photoanode for efficient water splitting

Abstract

Sunlight-driven photoelectrochemical (PEC) water splitting using earth-abundant semiconductor-based materials offers one promising strategy to produce attainable and sustainable carbon free energy. Herein, we demonstrate for the first time that a heterojunction nanostructure of a Bi/BiVO₄ photoanode is fabricated by directly coupling semimetal Bi nanoparticles to BiVO₄ nanoarrays, showing excellent water oxidation performance. The as-obtained photoanode exhibits a remarkable photocurrent density of 1.96 mA cm⁻² at 1.23 V versus a reversible hydrogen electrode (vs. RHE) under AM 1.5G (100 mW cm⁻²) irradiation, which is approximately 2-fold higher than that of the pristine BiVO₄. Based on the detailed analyses of J–V, i–t, M–S and EIS plots, the reason for the high photocurrent density of Bi/BiVO₄ can be attributed to the improved charge separation efficiency, the enhanced hole injection efficiency and the suppressed back reaction of water oxidation.