Recent progress in g-C₃N₄ based low cost photocatalytic system: Activity enhancement and emerging applications

Graphitic C₃N₄ (g-C₃N₄) has continuously attracted attention since it was reported as a metal-free semiconductor for water splitting. However, its ability to evolve hydrogen from water is significantly dependent on the use of noble metal co-catalyst, mainly Pt. In recent years, good progress has been achieved in developing co-catalysts containing earth abundant elements only for constructing low cost and efficient g-C₃N₄ based photocatalytic systems. Besides, exfoliation of bulk g-C₃N₄ into two dimensional g-C₃N₄ nanosheets offers large surface area and exposed active sites, which are beneficial for activity enhancement. Furthermore, oxygen evolution and CO₂ photoreduction over g-C₃N₄ have gained increasing interests due to the demand to achieve overall water splitting and conversion of CO₂ into chemicals and fuels. In this mini-review, we will briefly summarize the latest research works on g-C₃N₄ based photocatalytic systems during the last three years with emphasis on the progress achieved in enhancing the hydrogen evolution activity of g-C₃N₄ by loading noble metal free co-catalysts, exfoliating bulk g-C₃N₄ into nanosheets, and applying the g-C₃N₄ system in photocatalytic O₂ evolution and CO₂ reduction.