Highly dispersible graphitic carbon nitride: Synthesis and its 2-electron photocatalytic reduction activity of O2

Abstract Graphitic carbon nitride (g-CN) is a promising visible light-driven photocatalyst due to its favorable band gap. However, the limited number of active sites and rapid electron-hole recombination largely limit the photocatalytic efficiency of g-CN. This work provides a salt-template method (STM) to produce carbon nitride nanoparticles with high crystalline and dispersibility. 20-50 nm g-CN particles are achieved with high dispersion in aqueous phase, which permits a quasi-homogeneous aqueous photocatalytic oxidation and reduction conditions. It shows excellent photocatalytic activity for H2O2 generation and RhB degradation under visible light. An apparent H2O2 generation rate of 6.32 mmol·g−1·h−1 and an apparent RhB degradation rate constant (kapp) of 0.1707 min-1 were achieved on g-CN from salt-templated method, which are about 32 times and 2 times higher than that of g-CN derived from non-salt-template method, respectively. Increasing the crystallinity as well as reducing the g-CN nanoparticle size were found enhancing the electron-hole separation efficiency and resulting in more active sites. It offers a better and promising photocatalyst for H2O2 generation and organic pollution photodegradation.