From pure water to hydrogen peroxide on a novel 2,5,8-triamino-tri-s-triazine (melem)-derived photocatalyst with a high apparent quantum efficiency.

Photocatalytic hydrogen peroxide (HO) production is a green process but remains a great challenge. Herein, a novel photocatalyst with high activity for HO production, is developed based on 2,5,8-triamino-tri-s-triazine (melem) by linking it with 2, 3-naphthalene dicarboxylic anhydride (NDA). The obtained melem/NDA hybrid not only exhibited narrowed band gap and obviously enhanced visible light absorption, but also showed reduced charge recombination originated from its spatial distribution in HOMO and LUMO induced by the introduction of NDA as verified by DFT calculations. More significantly, the sufficient LUMO and HOMO positions for the optimal sample, melem/NDA, ensured efficient HO production from pure water via both the oxygen reduction reactions mainly through the two-step one-electron path and the water oxidation reaction through the one-step two-electron path. Consequently, melem/NDA achieves an apparent quantum efficiency of as high as 6.9 % at 420 nm. This work sheds light on developing high-performance organic photocatalysts for boosting photocatalytic HO production.