Interface engineering of BiVO₄/Zn₃V₂O₈ heterocatalysts for escalating the synergism: Impact of Cu electron mediator for overall water splitting

The risk of global warming is increasing due to excessive consumption of fossil fuels. To fill the gap between production and consumption of conventional energy sources, modern societies are searching green and renewable alternatives. In this work, BiVO₄/Zn₃V₂O₈ heterocatalysts were synthesized and interfacially engineered for overall water splitting reactions. To obtain the structural and interfacial morphologies, catalysts were characterized by XRD, FTIR, Raman spectroscopy, SEM and AFM techniques. The optical and chemical characteristics of as-synthesized catalysts were evaluated using UV–Vis/DRS, PL, EIS, EDX, XPS and BET analysis. The role of Cu metal, synergism between BiVO₄/Zn₃V₂O₈ and mechanistic approaches were further revealed. The results depict that Cu metal exceptionally compete to sustain the synergism as an electron mediator source. The synergistic effect and electron mediator were found as key factors to boost the overall water splitting efficiencies. Due to interfacial engineering of BiVO₄/Zn₃V₂O₈ system, charge transfer becomes more feasible for the redox reactions (i.e. water splitting). It was examined that due to presence of Cu metal, rate of overall water splitting reaction was higher than the catalysts having no mediator (i.e. absence of Cu). During photoreaction, two successive rates for H₂ and O₂ evolution were speculated 17.66 and 8.96 mmol g⁻¹ h⁻¹, respectively which delivers approximately 5.04 kJ g⁻¹ h⁻¹ energy. On the basis of results and activities, it could be concluded that, this research will exhibit exceptional potential and hold promise of an ultimate transition to the water splitting and green energy technologies.