Edge engineering of carbon nitride for enhanced sacrificial agent-free photocatalytic H2O2 evolution

Abstract

Photocatalytic oxygen reduction reaction (ORR) offers a green and sustainable route to produce H2O2. Electronic structure modulation and spin density distribution of the photocatalyst are crucial to the ORR activity. Heteroatom sulfur-doped and functionalized carbon nitride with abundant edge active sites is prepared for photocatalytic H2O2 generation. The as-obtained catalyst provides a faster H2O2 production rate of 416.7 μmol g−1h−1 under visible light (λ ≥ 420 nm) without using sacrificial agents. The enhanced photocatalytic performance is attributed to extended light absorption and improved carrier separation ability for the modulation of the electronic structure. The experimental and theoretic study demonstrates that sulfur doping and terminal group modulation show higher localized spin density, thus promoting the O2 absorption and the higher spin density and charge redistribution via edge active sites make the strong interaction between *OOH and the catalyst, which lowers the energy barrier of *OOH formation, thus facilitating the H2O2 generation.