Few-Layer Meets Crystalline Structure: Collaborative Efforts for Improving Photocatalytic H₂O₂ Generation over Carbon Nitride

Although the conversion of O 2 and H 2 O to H 2 O 2 over graphite carbon nitride (g-C 3 N 4 ) has been realized by means of the photocatalytic process, the catalytic activity of pristine g-C 3 N 4 is still restricted by the rapid charge recombination and inadequate exposure of the active site. In this work, we propose a straightforward strategy to solve these limitations by decreasing the thickness and improving the crystallinity of g-C 3 N 4, resulting in the preparation of few-layered crystalline carbon nitride (FL-CCN). Benefiting from the minimal thickness and highly ordered in-plane triangular cavities within the structure, FL-CCN processes an extended π-conjugated system with a reduced charge transfer resistance and expanded specific surface area. These features accelerate the efficiency of photogenerated charge separation in FL-CCN and contribute to explore of its surface active sites. Consequently, FL-CCN exhibits a significantly improved H 2 O 2 evolution rate (63.95 μmol g –1 h –1 ), which is 7.8 times higher than that of pristine g-C 3 N 4 (8.15 μmol g –1 h –1 ), during the photocatalytic conversion of O 2 and H 2 O. This systematic investigation offers valuable insights into the mechanism of photocatalytic H 2 O 2 generation and the development of efficient catalysts.