Anchored Cu single atoms on porous g-C3N4 for superior photocatalytic H2 evolution from water splitting

One of the most promising strategies for producing hydrogen is photocatalytic water splitting, in which the photocatalyst is a key component. Among many semiconductor photocatalysts, g-C3N4 has attracted great attention due to its narrow band gap, excellent stability and low cost. However, practical application is limited by its poor intrinsic activity. In this work, a high-performance porous g-C3N4 (PCN) photocatalyst with anchored Cu single atoms (CuSAs) was synthesized by a one-step co-heating approach. The obtained Cu1.5–PCN displays an excellent hydrogen evolution rate (HER) of 2142.4 μmol h−1 g−1 under visible light (=420 nm), which is around 15 and 109 times higher than those of PCN and bulk g-C3N4, respectively. In addition, it also shows good stability during H2 evolution. The results of experimental research and DFT simulations indicate that the single Cu ions formed bonds with the N-ring and these remain stable. Meanwhile, the special electronic structure of the Cu–N charge bridge extends the light absorption band to the visible-light region (380–700 nm). This high-performance and low-cost photocatalyst has great potential in solar energy conversion.