Exploring Bi₄V₂O₁₁ as Photoanode for Water Splitting with a Wide Range of Solar Light Capture and Suitable Band Potential

Bi₄V₂O₁₁ possesses a bandgap of ~1.9 eV, and the band positions of minimum conduction band and maximum valence band straddle the redox potentials of H⁺/H₂ and O₂/H₂O. In the current work, photoanode made of particulate Bi₄V₂O₁₁ film displays a wide range of light adsorption. However, when the anode was fabricated by drop-casting and examined for photoelectrochemical water splitting, the photocurrent density of the pristine Bi₄V₂O₁₁ was low. Improvement has then been carried out by Mo-doping. The Mo-doped Bi₄V₂O₁₁ photoanode achieves a maximum photocurrent density of 0.3 mA/cm² after a post deposition necking treatment to improve the connectivity of the drop-cast particles in the film. This material also shows a stability with maintaining 80% photocurrent after 2 h test. Discussion has been made on the displayed performance in PEC water splitting of the Bi₄V₂O₁₁ materials. Potential solutions have been proposed for this type of promising photoanode material for water splitting.