Insights into the improved photocatalytic performance of fluorine surface modified mpg-C3N4 at room temperature under aqueous conditions

Proposed mechanism for the synthesis of the fluorine-modified mpg-C3N4 photocatalyst. Display Omitted •The F surface modification mpg-C3N4 photocatalysts can be achieved by adjusting the pH values of aqueous solution.•The introduction of F atoms leads to the surface state and then optimizes band gap structure of mpg-C3N4.•The modified mpg-C3N4 shows potential application in environment purification. A novel fluorine surface modified mesoporous carbon nitride (mpg-C3N4) photocatalysts were synthesized by etching SiO2 with NH4HF2. The mechanism of formation and the factors that affect its photocatalytic activity were investigated. Interestingly, the introduction of F atoms improves the performance of surface state and widens the energy band gap of surface-modified mpg-C3N4 due to the higher separation and efficient mobility of the photoinduced carriers. Consequently, the fluorine-modified mpg-C3N4 exhibits higher carrier lifetime (8.64 ns) than mpg-C3N4 (7.14 ns), which improves the photocatalytic efficiency under ultraviolet light. The enhanced photocatalytic activity was evaluated by studying the degradation experiments of Rhodamine B. It is expected that the present fluorine modification at the surface of mpg-C3N4 may provide new insights in basic research and energy conversion.