Engineering oxygen into ultrathin graphitic carbon nitride: synergistic improvement of electron reduction and charge carrier dynamics for efficient photocatalysis

The fast separation rate of photogenerated carriers and the high utilization of sunlight are still a major challenge that restricts the practical application of carbon nitride (g-C3N4) materials in the field of photocatalytic hydrogen (H2) evolution. Here, ultrathin oxygen (O) engineered g-C3N4 (named UOCN) was successfully obtained by a facial gaseous template sacrificial agent-induced bottom-up strategy. The synergy of O doping and exfoliating bulk into an ultrathin structure is reported to simultaneously achieve high-efficiency separation of photogenerated carriers, enhance the utilization of sunlight, and improve the reduction ability of electrons to promote photocatalytic H2 evolution of UOCN. As a proof of concept, UOCN affords enhanced photocatalytic H2 evolution (93.78 μmol h−1) under visible light illumination, which was significantly better than that of bulk carbon nitride (named CN) with the value of 9.23 μmol h−1. Furthermore, the H2 evolution rate of UOCN at a longer wavelength (λ = 450 nm) was up to 3.92 μmol h−1 due to its extended light absorption range. This work presents a practicable strategy of coupling O dopants with ultrathin structures about g-C3N4 to achieve efficient photocatalytic H2 evolution. This integrated engineering strategy can develop a unique example for the rational design of innovative photocatalysts for energy innovation.