Which Type of Carbon Nitride More Suits Photocatalysis: Amorphous or Crystalline?

Graphitic carbon nitride (g-C3N4) has witnessed tremendous research interest due to its narrow bandgap, intrinsic 2D structure, and abundant raw materials. Although g-C3N4 has some shortcomings such as low specific surface area, poor conductivity and rapid charge carries recombination, various modification methods are constantly emerging to enhance its potential application value in photocatalysis. Increasing the crystallinity of g-C3N4 is an effective strategy to improve the in-plane charge separation efficiency. However, it is also reported that amorphous g-C3N4 possesses a higher adsorption and activation ability over reactants due to its richer surface functional groups than crystalline g-C3N4. Which type of g-C3N4 more suits photocatalysis, and which modification method is more suitable for boosting the activity of two types of g-C3N4, respectively? Based on these issues, the recent advances in the preparation and properties of amorphous and crystalline g-C3N4 are summarized, and their performance improvement strategies are overviewed thoroughly. Upon systematic comparison and analysis, which modification strategy is more suitable for the two types of g-C3N4, respectively, is proposed. Their applications are also summed up especially in environment remediation and energy conversation. Finally, the ongoing opportunities and future challenges for amorphous and crystalline g-C3N4 in the photocatalysis territory are taken for consideration. The recent advances in the preparation and properties of amorphous and crystalline g-C3N4 are summarized, and their performance improvement strategies are also overviewed thoroughly. Upon systematic comparison and analysis, the photocatalytic performance of both amorphous and crystalline g-C3N4 is summarized, offering their perspectives on which form is more suitable for photocatalytic applications. image