Construction of a bifunctional BiVO4 based S-scheme heterojunction for enhancing photothermal-photocatalytic oxygen generation and benzaldehyde production

In order to address the main challenges in photocatalysis, such as the recombination of photo-generated carriers and the limited absorption range of light, a successful strategy was developed by creating a photothermal-photocatalytic S-scheme heterojunction through the combination of CdS nanoparticles with BiVO4 nanorods. XPS analysis, as well as SPV results, revealed the establishment, direction, and strength of the internal electric field (IEF) in the created CdS/BiVO4 heterojunction. Due to the matched band structure and the strong IEF, the heterojunction followed the S-scheme transfer mode under light, inducing the strong redox ability and fast separation of photo-generated carriers. Besides that, the heat generated by incorporating a photothermal-effect during illumination also helped to boost the photocatalytic reaction. As a result, the engineered CdS/BiVO4 heterojunction exhibited an impressive benzaldehyde production of 17.45 mmol g−1·h−1, approximately four times higher than that of pure BiVO4 (3.70 mmol g−1·h−1). Furthermore, the oxygen evolution rate of the CdS/BiVO4 heterojunction was 3146.68 µmol·g−1, much higher than that of BiVO4 (1042.98 µmol·g−1). This study introduces a novel approach to overcome the fundamental obstacles in semiconductor photocatalysis, paving the way for enhanced overall performance.