Unveiling the cutting-edge progress in boosting the photoelectrochemical water-splitting efficiency of BiVO₄ photoanode with transition metal-based materials for sustainable hydrogen production

To address the significant depletion of fossil fuel reserves, hydrogen (H₂) fuel has emerged as a promising alternative energy source due to its eco-friendly nature and impressive efficiency. Over the years, research efforts have led to the development of various methods for producing H₂, with a particular focus on photoelectrochemical (PEC) water-splitting. Impressively, the interest in bismuth vanadate (BiVO₄) photoanode has been a research focus lately ascribed to its photosensitive characteristic and high electron mobility. Moreover, doping of metals, defects engineering, morphology modification, and synthesis of heterojunction material strategies have been exercised to further improve its PEC water-splitting activity. Consequently, several reviews have been published on the PEC performance of BiVO₄ modified with these strategies. However, to the best of our knowledge, there has been no comprehensive review specifically focusing on the impact of transition metal-based materials on the PEC performance of BiVO₄. In this context, we present a critical review of the recent developments involving the modification of BiVO₄ photoanode with transition metal-based materials for PEC water-splitting. Several transition metals such as nickel (Ni), cobalt (Co), iron (Fe), and tungsten (W) have been used in the recent development of BiVO₄-based photoanodes. Surprisingly, all of the modified BiVO₄ exhibited a substantial improvement in PEC activity with the photocurrent density at 1.23 V_RHE reaching as high as 10.3 mA/cm² has been reported in a previous study. Ultimately, this review highlights the promising potential of modified BiVO₄ for the PEC water-splitting application.