Nanocomposites of gold and modified g-C3N4 for enhanced hydrogen evolution via synergistic surface plasmon resonance and Schottky junction effects

Nanocomposites have demonstrated excellent performance as photocatalysts in various photocatalytic reactions. Herein, we developed a nanocomposite comprising modified graphitic carbon nitride (MCN) and gold nanoparticles (Au NPs) for the hydrogen evolution reaction (HER). The MCN was synthesized via co-polymerization of melamine and malonamide. The Au/MCN nanocomposite exhibited hydrogen evolution rates of 86.7 µmol·h − 1 ·g − 1 under visible light and 1281.2 µmol·h − 1 ·g − 1 under simulated sunlight, respectively. The photocatalytic HER rate of Au/MCN under simulated sunlight was enhanced by a factor of 99.3 compared to pristine g-C 3 N 4 nanosheet (CN). Controlled hydrogen evolution experiments confirmed the contribution of the surface plasmon resonance (SPR) effect. By combining HER results with conventional characterization and electrochemical tests, we elucidated the photocatalytic mechanism, revealing that the Schottky junction and SPR effect synergistically enhance the photocatalytic performance. The SPR effect was further verified by photocatalytic experiments and ultraviolet-visible diffuse reflectance spectroscopy.