Regulating directional transfer of electrons on polymeric g-C3N5 for highly efficient photocatalytic H2O2 production.

[Display omitted] • A novel metallic and non-metallic co-doped polymeric g-C 3 N 5 was fabricated. • K and I co-doping g-C 3 N 5 improved the photocatalytic H 2 O 2 production activity. • DFT calculations indicated that O 2 molecules serve as the electron trap sites. • K and I co-doping g-C 3 N 5 enhanced the adsorption and activation capacity of O 2. Graphite carbon nitride (g-C 3 N 5) has been widely used in various photocatalytic reactions due to its higher thermodynamic stability and better electronic properties compared to g-C 3 N 4. However, it is still challenging to endow g-C 3 N 5 with high performance on photocatalytic hydrogen peroxide (H 2 O 2) production. Herein, potassium and iodine are co-doped into g-C 3 N 5 (g-C 3 N 5 -K, I) for photocatalytic production of H 2 O 2 with high efficiency. As expected, the photocatalytic H 2 O 2 production rate over the g-C 3 N 5 -K, I (2933.4 μM h−1) reaches to 84.22 times as that of g-C 3 N 5. The excellent photocatalytic H 2 O 2 production activity is mainly ascribed to the co-doping of K and I, which significantly improves the capacity of oxygen (O 2) adsorption, selectivity of two-electrons oxygen reduction reaction (2e− ORR) and separation efficiency of charge carriers. The density functional theory (DFT) calculations reveal that O 2 molecules are more conducive to being adsorbed on g-C 3 N 5 -K, I. Besides, the result of excited states further indicates that photo-generated electrons can be directionally driven to the adsorbed O 2 molecules, which are effectively activated to form H 2 O 2. The findings will contribute to new insights in designing and synthesizing g-C 3 N 5 based photocatalysts for the H 2 O 2 production. [ABSTRACT FROM AUTHOR]