Rational Construction of Heterojunction of Bi₄V₂O₁₁/Au/ZnRh₂O₄ to Promote Photocatalytic Overall Water Splitting

Abstract

The rational design of heterojunction Z-scheme photocatalysts with controlled particle alignment is critical for improving the efficiency of overall water splitting. In this study, we report the fabrication of a Z-scheme photocatalyst composed of Bi₄V₂O₁₁ (BVO), Au nanoparticles and ZnRh₂O₄ (ZRO), with a focus on spatially aligning the constituent particles via an electrostatic assembly method. The surface of BVO was functionalized with 3-aminopropyltrimethoxysilane (APTMS) to promote the uniform deposition of Au nanoparticles, which subsequently enabled the anchoring of ZRO particles, forming a well-aligned heterojunction photocatalyst (BapAcZ). Structural and spectroscopic analyses confirmed the successful formation of the ternary composite with embedded Au between BVO and ZRO. Photocatalytic tests under monochromatic light at 700 nm revealed that BapAcZ exhibits significantly higher activity and reproducibility than randomly assembled composites, achieving an apparent quantum efficiency (AQE) of 4.7 × 10⁻² %, which is 1.8 times that of the control sample. These findings highlight the importance of particle-level structural engineering in designing efficient Z-scheme systems for solar water splitting and provide insights for further development of multi-component photocatalytic systems with precisely controlled architectures.