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

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.