PI/g-C₃N₄ composite photocatalyst with enhanced activity of degrading pollutants under visible light

Constructing heterojunction structure is of great significance for enhancing photocatalytic activity. Herein, a novel layered PI/g-C₃N₄ heterojunction was successfully prepared by a simple chemical adsorption method. The photocatalytic activity of PI/g-C₃N₄ heterojunction was determined by degradation of rhodamine B (RhB) under visible light. The 20PICN composite photocatalyst degraded RhB by 99% within 2 h, while pure g-C₃N₄ degraded RhB by only 69.9%. Moreover, the kinetic constant of 20PICN composite photocatalyst was 3.8 times that of g-C₃N₄. The 20PICN composite photocatalyst had excellent cycle stability. After five cycles of testing, the crystal structure had not changed and the ability to degrade RhB had not significantly decreased. It was found that h⁺ and ·O²⁻ were the main active species in the degradation process. The possible mechanism of PI/g-C₃N₄ degradation of RhB was explored. The formation of heterojunction improved the separation efficiency of photogenerated carriers, thereby enhancing its photocatalytic activity. This study provides a reference for the industrial production and application of g-C₃N₄-based metal-free photocatalyst.