Enhanced photocatalytic activity for degrading pollutants of g-C 3 N 4 by promoting oxygen adsorption after H 3 BO 3 modification

The g-C 3 N 4 has been modified by a hydrothermal post treatment with orthoboric acid. It is shown that the surface modification with an appropriate amount of orthoboric acid obviously enhances the surface photovoltage responses of g-C 3 N 4 , clearly indicating that the separation of photogenerated charges is greatly improved. This is well responsible for the enhanced photocatalytic activities for degrading representative gas-phase acetaldehyde, and liquid-phase phenol. Moreover, it is demonstrated that the amount of O 2 adsorbed on the surfaces of g-C 3 N 4 is greatly increased after H 3 BO 3 modification based on the O 2 temperature-programmed desorption curves. It is suggested that the orthoboric acid modification favors O 2 adsorption to promote the photogenerated electrons captured for improved photocatalytic activities. This work would provide feasible routes to further improve the photocatalytic performance of semiconductors for degrading pollutants.