Electronic Structure Regulations of Polymeric Carbon Nitride via Molecular Engineering for Enhanced Photocatalytic Activity

Polymeric carbon nitride (PCN) has initiated another wave of studies on its properties and behavior since the discovery of its photocatalytic ability. However, pristine PCN is unable to cope with the growing varieties of applications. Making PCN more adaptive to evolving conditions is one of the greatest challenges. Molecular engineering strategy proves to be a powerful tool to modify PCN with specified purpose, revealing that what is really appealing on PCN is its structural and electronic adjustability. By tuning the molecular structure of PCN, the in-plane electronic environment is accordingly changed, hence improving its photocatalytic activity. Herein, to further understand the relationship between the molecular structure of PCN and its photocatalytic performance, a comprehensive review on the recent progress of molecular engineering on PCN photocatalysts is presented. After introducing the fundamental properties of PCN and typical molecular engineering methodologies, the effects of different approaches of molecular structure modifications on the electronic structure of PCN are discussed in detail to unveil the role of molecular structures in electronic configuration regulation and the resultant photocatalytic performance. Finally, design principles of efficient PCN photocatalysts based on molecular engineering are provided, facilitating the understanding of its photocatalysis mechanism on the electronic level.