Solar Hydrogen Evolution Boosted by Cu and Pt Single-Atom Sites Anchored on g‑C₃N₄ via Magnetron Sputtering...

Photocatalytic hydrogen (H₂) evolution offers a promising solution to environmental pollution and the global energy crisis. Among different photocatalysts, graphitic carbon nitride (g-C₃N₄), most known as melon in the literature, is distinguished by its availability, large surface area, low cost, and unique optical and electrical properties. However, the efficiency of pristine g-C₃N₄ is limited by rapid electron-hole recombination, presence of charged trapped states and high charge transference resistance. To overcome these challenges, we used a facile magnetron sputtering technique to load Cu and Pt single atoms onto g-C₃N₄, confirmed by AC-STEM, XPS, ICP-OES, and XAS characterizations. This approach not only overcomes the problems related to the charge carrier dynamics of the pristine graphitic carbon nitride but also ensures uniform, contamination-free deposition and high distribution of single atoms, thereby optimizing photocatalytic performance. Under solar irradiation (AM 1.5G) for 5 h, the Cu and Pt-loaded g-C₃N₄ demonstrated significantly improved photocatalytic activity, achieving H₂ accumulated values of 93 μmol and 173 μmol, respectively, compared to only 0.3 μmol for pristine g-C₃N₄. For comparison, Pt and Cu nanoparticles (NPs)- loaded g-C₃N₄ samples were also prepared, achieving H₂ accumulation values of 86.3 and 24.3 μmol, respectively, compared to pristine g-C₃N₄. However, these values are lower than those of Pt and Cu single-atom-loaded samples. The enhanced H₂ evolution performance is attributed to the deposition of metal single atoms acting as electron traps and active catalytic sites, thus improving electron-hole separation. These findings highlight the potential of sputter depositing single-atom to overcome the inherent limitations of g-C₃N₄, paving the way for more efficient and scalable hydrogen production systems.