Effective Breaking of the Fluorocarbon Chain by the Interface Bi2O2X···PFOA Complex Strategy via Coordinated Se on Construction of the Internal Photogenerated Carrier Pathway.

Abstract

The destruction of perfluorooctanoic acid (PFOA) from outside was inhibited by the "barrel spiral" barrier, but the construction of the photocatalyst-PFOA complex provided a direct attack on photogenerated reactive species (RSs). Here, we investigated the bridging ability of bismuth oxychalcogenide (Bi2O2X) for constructing an effective photocarrier pathway to PFOA. The experimental results and DFT calculations showed that a more intense internal access of Bi2O2Se was built via the terminal carboxylate tail, and the weaker electrostatic interaction of Bi-Se bonds helped realize the smaller band gap and slower recombination of photocarriers, thereby inhibiting the invalid annihilation of holes with H2O and facilitating the transformation of electrons to O2-•. The pseudo-first-order rate coefficient (kobs) was 2 and 4 times higher than Bi2O2S and TiO2, respectively, showing the outstanding photocatalytic activity of Bi2O2Se. A broad pH (4-8) adaptability of Bi2O2Se was observed for defluorination, especially in alkali condition. This new understanding may inspire the development of Se-coordinated catalysts.