Graphite carbon nitride photocatalytic materials: A roadmap to modification for current and future water purification

Graphite carbon nitride (g-C3N4), as a metal-free photocatalytic material, has been widely used in the field of water purification due to its advantages of abundant raw materials, low cost, simple preparation, strong stability, and environmental friendliness. However, the photocatalytic performance of pure g-C3N4 is dramatically reduced due to the fast recombination of photoelectron-hole, low light absorption rate, and easy agglomeration. Therefore, in recent years, a series of modification methods were developed to improve the photocatalytic efficiency of g-C3N4, which were experimentally proved with outstanding water purification performance in face of various pollutants (dyes, antibiotics, metal ions, microbiology, etc.). The purpose of this review is to provide insight into these novel approaches to the design and modification of g-C3N4. Then, the corresponding applications in water purification of such emerging new g-C3N4-based photocatalysts are also summarized. Finally, the challenges and future opportunities for their practical applications are also intensively highlighted.