Phase engineering induces electron redistribution to turn periodate activation activity of MoS2

Abstract

MoS2-based materials are promising in the field of wastewater treatment. However, the potential application and intrinsic mechanism of MoS2-driven periodate (PI) remains unclear. Here, the MoS2 materials with different 1T/2H ratios, which were characterized by XRD, Raman and XPS were synthesized. The MoS2/PI system could signally promote oxytetracycline (OTC) degradation under dark conditions and 1T/2H ratio of MoS2 has a noticeable effect on the catalytic performance. Specially, the kobs of L-1T-MoS2 (50% 1T phase) was 1.59 and 3.62 times of H-1T-MoS2 (∼74% 1T phase) and 2H-MoS2 (100% 2H phase). The results of quenching experiments, EPR, EIS, I-t and Tafel polarization curves showed that •OH and 1O2, rather than O2•−, H2O2, IO3•, high-valent oxide oxidation and electron transfer, played important roles in MoS2/PI systems. XPS analysis and DFT calculations revealed that Mo was the primary site and phase engineering increased the electron density of Mo sites in MoS2, thereby regulating the activation of PI. These results would enrich understandings on phase engineering of MoS2 to turn its catalytic performance for OTC degradation.