Tailoring hydrophilicity and electronic interactions and transfer: Enhancing hydrogen production through size-tuned CuNi alloys

[Display omitted] •CuNi nanoalloys of different sizes were supported on Al-STO via hydrothermal and impregnation reduction methods.•The size effect of CuNi nanoalloys significantly influences the interaction and transfer of charges.•CuNi nanoalloys with larger particle sizes exhibit outstanding hydrophilicity.•The size of CuNi nanoalloys also affects theactivity in photocatalytic hydrogen evolution reaction. Investigating eco-friendly, effective, and economical cocatalysts for photocatalytic hydrogen evolution remains a significant challenge. In this research, different methods were utilized to synthesize CuNi nanoalloys of varied particle sizes supported on Al-doped SrTiO3 (Al-STO), delving into the effects of CuNi alloy particle size, catalyst material hydrophilicity, and charge dynamics on photocatalytic efficiency. The study meticulously examined how different particle sizes of CuNi alloys impacted the photocatalytic activity of Al-STO, noting that larger CuNi alloy nanoparticles significantly enhance and stabilize photocatalytic hydrogen evolution, achieving a rate of 58.14 µmol/h. A detailed comparative analysis was also conducted, focusing on the nanoalloys' distribution, elemental composition, and optical characteristics, thereby elucidating the critical role of particle size in influencing the physicochemical properties of CuNi nanoalloys. Furthermore, comprehensive Density Functional Theory (DFT) calculations were carried out to confirm the robust interactions between the alloy and support, as well as the electronic synergies within the CuNi alloy components. These interactions are shown to greatly affect charge transfer efficiency and the adsorption energy of the reactants, such as water molecules. This investigation paves the way for adopting non-precious bimetallic cocatalysts in efficient photocatalytic hydrogen production, offering valuable insights for future clean energy research endeavors.