Molybdenum (VI)-oxo Clusters Incorporation Activates g-C3N4 with Simultaneously Regulating Charge Transfer and Reaction Centers for Boosting Photocatalytic Performance

Establishing local built-in electric field of 2D semiconductors is one of the promising strategies to regulate the oriented charge delivery to active centers for enhancing photocatalytic performance. Herein, a novel heptamolybdate polyanions-intercalated porous g-C3N4 ([Mo7O24](6-)-pCN) catalyst with integrating highly desirable visible-light photocatalytic features is reported. After intercalation, the apparent reaction rate constants (k(app)) of [Mo7O24](6-)-pCN for bisphenol A (BPA) and 4-chlorophenol (4-CP) photodegradation are remarkably enhanced, which are 9.0 and 6.4 times faster than those of pCN, respectively. Analogously, the k(app) values of [Mo7O24](6-)-CN for BPA and 4-CP removal are also improved by contrast with CN. The experimental results and density functional theory calculations indicate that a local built-in electric field is formed in [Mo7O24](6-)-pCN with a polarization direction from aromatic rings of g-C3N4 to the inserted [Mo7O24](6-) clusters. Driven by the electric field, photogenerated carriers can be efficiently separated for better reactive oxidative species (ROSs) production. These O atoms are also proved as adsorption sites for phenols, greatly reducing the migration distance of ROSs and thus improving photocatalytic performances. This work offers a reliable strategy to construct local built-in electric field via polyoxometalates intercalation for effective solar energy conversion and phenolic wastewater remediation.

Automated summary

A novel porous g-C3N4 catalyst with heptamolybdate polyanions intercalation is reported, which establishes a local built-in electric field for enhancing the photocatalytic performance.