Effect of noble metal ions dopants on solar photoelectrochemical water splitting and electrochemical supercapacitive performance of BiVO₄ hollow tubes

Owing to their poor electrochemical properties, photoelectrochemical (PEC) solar water splitting and electrochemical energy storage activity of BiVO₄ are presently limited in their applications. One of the effective methods for improving electrochemical activity is the doping of noble-metal ions into the host lattice. The doping of noble-metal ions can improve absorption in visible light and support the direct transfer of energy via hot electrons. In this study, the synthesis of Au-doped BiVO₄ nanostructured catalysts with different concentrations of Au ions was prepared via a template-free ultrasonication technique, and it's both solar-driven PEC water splitting and electrochemical storage properties were examined. The optimal doped photoelectrode exhibited a lower resistance to charge transfer than other photoelectrodes, including a significant enhancement in photocurrent density (0.102 mAcm⁻²), which is approximately 4.1 times superior over undoped photoanode. Furthermore, the optimal doped electrode exhibited an electrochemical capacitance that is 2 times greater than that of the pure electrode. The excellent electrochemical behavior and PEC properties of the optimal doped electrode were attributed to the increase in surface area and suitable band gap. Consequently, enables the dispersion of electron at the interface of electrode/electrolyte. Solar PEC solar water splitting and supercapacitor performance of the optimal doped electrodes were significantly improved by the proper incorporation of Au ions.