Facile synthesis of porous C-doped C3N4: fast charge separation and enhanced photocatalytic hydrogen evolution

Abstract

Metal-free graphitic carbon nitride (g-C₃N₄) is a promising semiconductor material that can utilize visible light for photocatalytic hydrogen production. The photocatalytic activity can be further enhanced by improving the kinetics of photocarrier transfer and absorption efficiency of visible light. Herein, we demonstrate a facile strategy for the synthesis of C-doped g-C₃N₄ with porous hierarchical structure by simple co-pyrolyzation of acrylamide and dicyandiamide together. The addition of trace amount of acrylamide not only endows g-C₃N₄ with high porosity and specific surface area, but also promotes electron–hole separation and charge transfer due to the introduction of carbon dopant into the g-C₃N₄ structure. With 2 wt% of acrylamide in the precursor, the resulted C-doped g-C₃N₄ can deliver 3.4 times higher photocatalytic activity for hydrogen evolution than that of the bulk g-C₃N₄. Our present work provides valuable information for the performance-based optimization of composition and structural properties, as well as large scale production of high performance g-C₃N₄ photocatalysts.