Central nitrogen vacancies in polymeric carbon nitride for boosted photocatalytic H₂O₂ production

Polymeric carbon nitride (PCN) with vacancies usually exhibits distinguished mass transfer efficiency, outstanding carrier kinetics and excellent photoactivity. Previous studies have revealed the effect of edge vacancies in heptazine units of PCN; however, the roles of central nitrogen vacancies are scarcely investigated. Herein, central nitrogen vacancies polymeric carbon nitride (PCN-NV_C) is rationally prepared for photocatalytic H₂O₂ production with a rate of 25.1 umol/h (λ > 420 nm), which is 3.5 times than that of pristine PCN. Photoelectronic measurements reveal that the central nitrogen vacancies optimize the kinetic process of electron-hole pairs. Density functional theory (DFT) calculations disclose that PCN-NV_C displays lower O₂ adsorption energy, thereby accelerating the OOH* formation and decreasing the H₂O₂ generation energy barrier. This work not only provides a strategy for constructing central nitrogen vacancies polymeric carbon nitrogen, but also affords a deep understanding of its roles in photocatalytic H₂O₂ production.