Strategies to enhance photocatalytic activity of graphite carbon nitride-based photocatalysts

With the rapid development of photocatalysis field, photocatalysts have received increasing attention due to their important role in environmental pollution and energy crisis. As a nonmetallic polymeric material, graphite carbon nitride (g-C3N4) is rich in sources and its preparation is simple, and thus has been widely used as a visible-light-responsive photocatalyst. In this review, we have summarized the recent progress related to the design, modification, and construction of g-C3N4 based photocatalysts with excellent photocatalytic performances. First, we have described the basic structure and properties of g-C3N4. Thereafter, we have pointed out that the defects of pristine g-C3N4 and illustrated the general design principles for all of modified strategies. Subsequently, we have discussed various strategies to optimize the photocatalytic properties of g-C3N4 in detail, including constructing Z-scheme heterojunctions based on g-C3N4, morphological controlling, metal deposition, ion doping, dye sensitization, quantum dots modification, and acid treatment. Particularly, we have comprehensively explicated the critical factors governing the performance of the photocatalyst and the enhanced photocatalytic mechanisms of each modification strategy with examples. Finally, we have indicated the challenges of photocatalysis technology using g-C3N4 and proposed the opportunities for further development.