Tuning the Photocatalytic Performance of Tungsten Oxide by Incorporating Cu₃V₂O₈ Nanoparticles for H₂ Evolution Under Visible Light Irradiation

The green energy production through water splitting under visible light irradiation has become an emerging challenge in the 21st century. Photocatalysis, being a cost-competitive and efficient technique, has grabbed much more attention for environmental applications, especially for hydrogen evolution. In this article, the hybrid Cu₃V₂O₈-WO₃ nanostructures were prepared through the hydrothermal method by using copper acetate, ammonium metavanadate, and Na₂WO₄ · 2H₂O as precursors. The varying contents of Cu₃V₂O₈ in WO₃ were 0.2%, 0.5%, 1.0%, 2.0%, and 3.0%. The X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), UV-Vis, and photoluminescence (PL) emission spectroscopy were used to investigate the structural, morphological, surface area, and optical properties of prepared samples. The average crystalline size of the pure WO₃ ranges from 10 to 15 nm and 70 to 195 nm for an optimal composite sample. The structural phase of the hybrid WO₃-Cu₃V₂O₈ nanoparticles was found to transfer from monoclinic to hexagonal by incorporating the Cu₃V₂O₈ contents. The enhanced photocatalytic performance for hydrogen evolution was observed for 2% Cu₃V₂O₈-WO₃ composite sample. The key to this enhancement lies at the heterojunction interface, where charge separation occurs. In addition, the excellent photocatalytic activity was attributed to a higher surface area, efficient charge separation, and extended visible light absorption. This work provides an in-depth understanding of efficient separation of charge carriers and transfer processes and steer charge flow for efficient solar-to-chemical energy applications.