Single‐Atom Catalysts on C₃N₄: Minimizing Single Atom Pt Loading for Maximized Photocatalytic Hydrogen Production Efficiency

Abstract The use of metal single atoms (SAs) as co‐catalysts on semiconductors has emerged as a promising technology to enhance their photocatalytic hydrogen production performance. In this study, we describe the deposition of very low amounts of Pt SAs (<0.1 at %) on exfoliated graphitic carbon nitride (C 3 N 4 ) by a direct Pt−deposition approach from highly dilute chloroplatinic acid precursors. We find that − using this technique−a remarkably low loading of highly dispersed Pt SAs (0.03 wt %) on C 3 N 4 is sufficient to achieve a drastic decrease in the overall charge transfer resistance and a maximized photocatalytic efficiency. The resulting low‐loaded Pt SAs/C 3 N 4 provides a H 2 production rate of 1.66 m mol/h/mg Pt, with a remarkable stability against agglomeration; even during prolonged photocatalytic reactions no sign of light‐induced Pt agglomerations can be observed. We ascribe the high performance and stability to the site‐selective, stable coordination of Pt within the C 3 N 4 structure. Notably the H 2 production rate of the low‐loaded Pt SAs surpasses the activity of Pt SAs deposited by other techniques or nanoparticles at comparable or even higher loading – the optimized Pt SAs decorated C 3 N 4 show ≈5.9 times higher rate than Pt NP decorated C 3 N 4 .