Enhanced charge carrier separation and stable photoelectrochemical water splitting via a high-performance BiVO4/BiOBr Type-II heterojunction

The development of an ideal photoanode that exhibits broad light absorption, efficient photogenerated carrier separation, and superior transmission efficiency remains a pivotal challenge in enhancing the sluggish photoelectrochemical (PEC) water splitting reaction. Here, we present an efficacious strategy to bolster the PEC performance of oxygen evolution by fabricating a BiVO4/BiOBr heterojunction through a combined electrochemical deposition-calcination approach and the successive ionic layer adsorption and reaction (SILAR) method. The band structure of BiOBr is optimally aligned with BiVO4, enabling the heterojunction to significantly enhance the separation efficiency of photogenerated charges and accelerate the kinetics of PEC water oxidation. Under simulated sunlight irradiation, the BiVO4/BiOBr heterojunction exhibits a remarkable photocurrent density of 2.69 mA/cm(2) at 1.23 V vs. reversible hydrogen electrode (RHE), surpassing the performance of bare BiVO4 film (0.46 mA/cm(2) at 1.23 V vs. RHE) and demonstrating exceptional stability. This work offers novel insights into the rational design and fabrication of solar-driven PEC water splitting photoanodes.