Photocharged carbon nitride with local electron accumulation: Towards outstanding round-the-clock hydrogen peroxide production

Prolonging the lifetime of photogenerated electrons is crucial not only for improving surface photocatalytic reactions under light irradiation, but also for developing round-the-clock applications to overcome solar intermittency. Herein, edge nitrogen vacancies were introduced into K-doped polymeric carbon nitride through a CCl4 assisted molten salt calcination method. The electron lifetime was successfully extended to days by forming photocharged active electron storage equivalents akin to natural photosynthesis. This timescale is far beyond the requirement for surface photocatalytic O2 reduction to H2O2, therefore, an unprecedented photocatalytic H2O2 production rate of 10.02 mmol L-1 h−1 was achieved under visible light, which is 176 times that of pristine carbon nitride and significantly higher than those of the state-of-the-art photocatalysts. Meantime, the stored electrons endow the photocatalyst with a delayed photocatalytic H2O2 evolution ability, allowing the novel prototype of round-the-clock H2O2 evolution to be realized. This intriguing character is ascribed to the strong local electron accumulation at the edge nitrogen vacancies, which realizes the photocharging effect and enhances electron transfer to chemisorbed O2. This work would deepen the understanding and pave the way for designing efficient photocatalysts for round-the-clock applications.