The mechanistic difference of 1T-2H MoS2 homojunctions in persulfates activation: Structure-dependent oxidation pathways

Two-dimensional layered MoS 2 recently demonstrates great potentials in water purification via adsorption and catalysis. The structure-catalysis relationship of MoS 2 has not been well addressed. Herein, we investigated the mechanistic difference of 1 T-2H MoS 2 homojunctions in catalytic activation of peroxymonosulfate (PMS) and peroxydisulfate (PDS) for degrading butyl paraben (BPB). PMS/1 T-2H MoS 2 attains higher performance in BPB removal compared to PDS/1 T-2H MoS 2 . 1 T phase in MoS 2 primarily contributed to PMS activation to produce SO 4 − , OH and 1 O 2 , while the defects in MoS 2 coordinated the PDS activation to generate OH, 1 O 2 and O 2 − . Nevertheless, OH-induced BPB removal was the top priority for PMS/1 T-2H MoS 2 and PDS/1 T-2H MoS 2 . The different activation pathways and reactive species resulted in the varying BPB removal, by-product distributions and toxicity. This work provides new insights into the different functions of MoS 2 in persulfates activation and the guidance in rational design of oxidant-oriented MoS 2 composites for sewage purification.