Rational design of donor-acceptor engineered g-C3N4 for boosted H2O2 production via photocatalytic O2 reduction

Artificial photo-driving 2e- oxygen reduction reaction (ORR) offers a promising strategy for H2O2 production, while the O2-to-H2O2 conversion suffers from low activity and selectivity. Herein, by grafting thiophene (TP) onto the edge of g-C3N4, we develop a donor-acceptor-engineered catalyst (g-C3N4-TP) for efficient H2O2 production. The optimized g-C3N4-TP exhibits an H2O2 production rate of 552 mu mol g-1 h-1 under visible irradiation with an apparent quantum yield of 3.2 % at 420 nm, which is ca. 4 times that of pristine g-C3N4. Experiments and theoretical calculations identify that the enhanced photocatalytic performance is ascribed to the introduced TP units, which are capable of promoting the separation of electron-hole pairs, altering the adsorption mode of O2, and reducing the energy barriers for H2O2 production. This work deepens the understanding of O2 adsorption and conversion on g-C3N4, paving a new way for efficient H2O2 production by rational designing donor-acceptorengineered photocatalysts.