State-of-the-art progress in overall water splitting of carbon nitride based photocatalysts

Converting solar energy into hydrogen (H₂) by photocatalytic water splitting is a promising approach to simultaneously address the increasing energy demand and environmental issues. Half decade has passed since the discovery of photo-induced water splitting phenomenon on TiO₂ photoanode, while the solar to H₂ efficiency is still around 1%, far below the least industrial requirement. Therefore, developing efficient photocatalyst with a high energy conversion efficiency is still one of the main tasks to be overcome. Graphitic carbon nitride (g-C₃N₄) is just such an emerging and potential semiconductor. Therefore, in this review, the state-of-the-art advances in g-C₃N₄ based photocatalysts for overall water splitting were summarized in three sections according to the strategies used, and future challenges and new directions were discussed.