The developments in carbon-modified graphitic carbon nitride for photoelectrochemical water splitting: a mini review

Graphitic carbon nitride (g-CN), as a potential photoelectrode for photoelectrochemical water splitting, has garnered significant research attention owing to its favorable attributes, including a suitable bandgap, abundant elemental composition, excellent thermal stability, and non-toxicity. However, the limited efficiency of visible light absorption and poor electrical conductivity of pure g-CN result in low photocurrent density and photocatalytic activity, falling short of meeting the requirements for commercial applications. In contrast, graphitic carbon materials possess high conductivity and stability, appearing to be an excellent candidate for enhancing the photocatalytic performance of g-CN while maintaining its stability. Recently, nitrogen vacancies, surface junction, carbon crystallite introduction, and carbon atom doping methods have been employed to prepare carbon-modified g-CN. The introduced π-electron conjugated system by sp²-hybridized carbon atoms indeed extends the visible light absorption and photocurrent of g-CN, resulting in improved photocatalytic performance. In this review, we highlight recent advancements in the development of carbon-modified g-CN and offer insights into the future prospects of g-CN-based films.