Hollow polymeric ionic liquid spheres with hierarchical electron distribution: A novel composite of g-C₃N₄ for visible light photocatalytic water splitting enhancement

Graphitic carbon nitride (g-C₃N₄) has been considered as a promising organic semiconductor for photochemistry but under great challenges of severe recombination rate of photogenerated electron-hole pairs, the weak ability of light harvesting, and other inherent defects. Herein, uniformed hollow polymeric ionic liquid spheres with layer gradients of electron structure were developed innovatively combining with g-C₃N₄ nanosheets driven by sonication and electrostatic forces. These two components can form a novel system due to the distinction of electron between poly(ionic liquids) (PILs) and g-C₃N₄. The novel as-developed PILs-x loaded on the g-C₃N₄ surface benefits the transfer and supplement of photoinduced electrons resulting from the effects of “electronic reservoir”. Meanwhile, the light harvesting of the PILs-x/g-C₃N₄ is also enhanced significantly. In addition, the “ion modulated effect” was studied by tuning the species of anion in PILs structure, achieving controllable regulation of photocatalytic activity. Benefiting from the above fascinating properties, the PILs-x/g-C₃N₄ system exhibit a significantly enhanced hydrogen evolution efficiency with Pt as co-catalyst under visible light irradiation compared with the Pt/PCN. This study opens a new sight to strengthen the photocatalytic activity of g-C₃N₄ by using functional hollow PILs with layer gradients of electron structure for various applications in energy and environmental fields.