Abstract
The graphdiyne (GDY) used in this study was prepared by mechanochemical method, and it was loaded in situ on Ag2Mo2O7 by hydrothermal method to synthesize GDY/Ag2Mo2O7 (G/AMO), which was used for photocatalytic coupling of peroxydisulfate (PDS) activation and degradation of 2,4-dichlorophenol (2,4-DCP). When 20 mg G/AMO-2.5 was added and the concentration of PDS was 1.0 g/L, 98 % 10 mg/L 2,4-DCP could be degraded within 60 min, and the rate constant was 0.0144 min−1. The influence factor experiments showed that HCO3–, CO32– and H2PO4- favored the degradation of 2,4-DCP and that G/AMO-2.5 had good cyclic stability. According to the capture experiments as well as the ESR test results, the role of degradation actives: ·OH > h+ > SO4·-, the addition of PDS produces SO4·- under photoexcitation, which synergizes with the original ·OH and h+ in the system to further degrade 2,4-DCP. The electronic structure, theoretical bandgap and density of states of the material were calculated by density-functional theory (DFT), and the degradation mechanism was hypothesized in combination with the experimentally obtained bandgap structures: the loading of Ag2Mo2O7 on GDY formed an internal electric field, constructed an S-scheme heterojunction, and inhibited the complexation of the photogenerated charges, which improved the performance of the activated PDS in the degradation of 2,4-DCP. In this paper, a method is provided for the construction of S-scheme heterojunction photocatalysts to activate PDS to degrade pollutants.
Published Version
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