BiVO₄ Photoanode with Exposed (040) Facets for Enhanced Photoelectrochemical Performance

A BiVO₄ photoanode with exposed (040) facets was prepared to enhance its photoelectrochemical performance. The exposure of the (040) crystal planes of the BiVO₄ film was induced by adding NaCl to the precursor solution. The as-prepared BiVO₄ photoanode exhibits higher solar-light absorption and charge-separation efficiency compared to those of an anode prepared without adding NaCl. To our knowledge, the photocurrent density (1.26 mA cm^-2 at 1.23 V vs. RHE) of as-prepared BiVO₄ photoanode is the highest according to the reports for bare BiVO₄ films under simulated AM1.5G solar light, and the incident photon-to-current conversion efficiency is above 35% at 400 nm. The photoelectrochemical (PEC) water-splitting performance was also dramatically improved with a hydrogen evolution rate of 9.11 μmol cm^-2 h^-1, which is five times compared with the BiVO₄ photoanode prepared without NaCl (1.82 μmol cm^-2 h^-1). Intensity-modulated photocurrent spectroscopy and transient photocurrent measurements show a higher charge-carrier-transfer rate for this photoanode. These results demonstrate a promising approach for the development of high-performance BiVO₄ photoanodes which can be used for efficient PEC water splitting and degradation of organic pollutants.