Nitrogen vacancy induced in situ g-CN p-n homojunction for boosting visible light-driven hydrogen evolution.

Graphitic carbon nitride (g-CN) as a novel photocatalyst with great potentials has been extensively employed in solar-driven energy conversion. Herein, the novel in situ g-CN p-n homojunction photocatalyst with nitrogen vacancies (NV-g-CN) is successfully fabricated via hydrothermal synthesis followed by two-step calcination. The in situ NV-g-CN homojunction can be employed as an effective photocatalyst for hydrogen generation through water splitting under visible light, and the optimum rate constant of 3259.1 μmolgh is achieved, which is 8.7 times as high as that of pristine g-CN. Moreover, the markedly increased photocatalytic performance is ascribed to the enhanced light utilization, large specific surface area and unique nitrogen-vacated p-n homojunction structure, which provides more active sites and improves the separation of photo-excited electron-hole pairs. Besides, the underlying mechanism for efficient charge transportation and separation is also proposed. This work demonstrates that the remodeling of g-CN p-n homojunction with nitrogen vacancies is a feasible way as highly efficient photocatalysts and might inspire some new strategies for energy and environmental applications.