Gold nanoparticle, surface plasmon resonance enhanced visible-light-driven debromination of tetrabromodiphenyl ethers by ZnIn2S4

2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) is a highly toxic organic pollutant. Owing to the high structural stability, BDE-47 is difficult to be naturally decomposed. In this study, Au nanoparticles decorated flower-like ZnIn 2 S 4 microspheres were successfully fabricated and applied for the rapid removal of BDE-47 driven by visible-light irradiation. It was revealed that 3 wt% Au-loaded ZnIn 2 S 4 (Au/ZnIn 2 S 4 ) has the highest removal rate for BDE-47 (0.90118 h −1 ). A study of the reaction path and mechanism shows that the bromine adjacent to the oxygen atom in BDE-47 tends to be removed via electron transfer. This is attributed to the band-gap excitation of ZnIn 2 S 4 , the surface plasmon resonance effect of the Au nanoparticles, and the Schottky junctions between them. Furthermore, density functional theory calculations show that the strong affinity between Au 0 and the bromine atom adjacent to the oxygen atom in BDE-47 can lengthen the carbon–bromine bond and further weaken the bond upon the accumulation of electrons. This may be the main reason for the rapid debromination of BDE-47. This study provides a new perspective on the photocatalytic removal of moderately brominated polybrominated diphenyl ethers.