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

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 (C3N4) 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 (0.03wt%) on C3N4 is sufficient to achieve a drastic decrease in the overall charge transfer resistance and a maximized photocatalytic efficiency. The resulting low‐loaded Pt SAs/C3N4 provides a H2 production rate of 1.66 mmol/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 C3N4 structure. Notably the H2 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 C3N4 show ≈5.9 times higher rate than Pt NP decorated C3N4.