BiVO₄ Ceramic Photoanode with Enhanced Photoelectrochemical Stability

Monoclinic bismuth vanadate (BiVO₄) is an attractive material with which to fabricate photoanodes due to its suitable band structure and excellent photoelectrochemical (PEC) performance. However, the poor PEC stability originating from its severe photo-corrosion greatly restricts its practical applications. In this paper, pristine and Mo doped BiVO₄ ceramics were prepared using the spark plasma sintering (SPS) method, and their photoelectrochemical properties as photoanodes were investigated. The as-prepared 1% Mo doped BiVO₄ ceramic (Mo-BVO (C)) photoanode exhibited enhanced PEC stability compared to 1% Mo doped BiVO₄ films on fluorine doped Tin Oxide (FTO) coated glass substrates (Mo-BVO). Mo-BVO (C) exhibited a photocurrent density of 0.54 mA/cm² and remained stable for 10 h at 1.23 V vs. reversible hydrogen electrode (RHE), while the photocurrent density of the Mo-BVO decreased from 0.66 mA/cm² to 0.11 mA/cm² at 1.23 V vs. RHE in 4 h. The experimental results indicated that the enhanced PEC stability of the Mo-BVO (C) could be attributed to its higher crystallinity, which could effectively inhibit the dissociation of vanadium in BiVO₄ during the PEC process. This work may illustrate a novel ceramic design for the improvement of the stability of BiVO₄ photoanodes, and might provide a general strategy for the improvement of the PEC stability of metal oxide photoanodes.