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 (Bi 2 O 2 X) for constructing an effective photocarrier pathway to PFOA. The experimental results and DFT calculations showed that a more intense internal access of Bi 2 O 2 Se 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 H 2 O and facilitating the transformation of electrons to O 2 -• . The pseudo-first-order rate coefficient ( k obs ) was 2 and 4 times higher than Bi 2 O 2 S and TiO 2 , respectively, showing the outstanding photocatalytic activity of Bi 2 O 2 Se. A broad pH (4-8) adaptability of Bi 2 O 2 Se was observed for defluorination, especially in alkali condition. This new understanding may inspire the development of Se-coordinated catalysts.