In situ photodeposition of Cu and Ni(OH)₂ dual cocatalyst: Synergistic effect on enhancing g-C₃N₄ photocatalytic H₂ evolution

The hydrogen generated through photocatalytic technology is crucial for environmental resources and energy supply. The key to solving photocatalytic efficiency is the migration and compounding of photogenerated carriers. In this paper, Cu is chosen as an electron co-catalyst with good metallic properties to replace the expensive metal. Meanwhile, Ni(OH)₂ unites with g-C₃N₄ to facilitate hole transfer as a hole co-catalyst. The data shows that the g-C₃N₄ photocatalyst using Cu and Ni(OH)₂ as modified co-catalyst has the maximum hydrogen evolution efficiency (2037.3 μmol·g⁻¹·h⁻¹). Due to the Ni(OH)₂ and Cu nanoparticles combined with g-C₃N₄ and their synergistic effect, the hydrogen evolution activity of the dual-loaded photocatalyst is higher than the sum of that of the single-loaded Cu-C₃N₄ (303.6 μmol·g⁻¹·h⁻¹) and Ni(OH)₂-C₃N₄ (447.3 μmol·g⁻¹·h⁻¹). The photoluminescence spectra (PL) showed that Cu-Ni(OH)₂-C₃N₄ possessed the lowest carrier recombination rate and the fastest carrier transfer rate, consistent with the hydrogen evolution performance results. Data from electrochemical workstations show that composite samples owned a lower electrochemical impedance. The above experiments indicate that the double-loaded synergistic catalytic g-C₃N₄ possesses a more vital photocatalytic driving force, which has implications for studying energy-catalytic conversion.