Titanium Carbide Composite Hollow Cobalt Sulfide Heterojunction with Function of Promoting Electron Migration for Efficiency Photo-Assisted Electro-Fenton Cathode

Constructing heterostructure within electrocatalysts proves to be an attractive approach to adjust the interfacial charge redistribution to promote the adsorption of reactive species and accelerate the charge transfer. Herein, we present the one-pot solvothermal synthesis of Ti3C2 supported hollow CoS2/CoS microsphere heterostructure with uneven charge distribution as the cathodic catalyst, which displays a superior quasi-first-order degradation rate (0.031 min−1) for sulfamethazine (SMT) in photo-assisted electric–Fenton (EF) process. CoS2/CoS/Ti3C2 is proven to favor the 2e− oxygen reduction reaction (ORR), with H2O2 selectivity up to 76%. The built-in potential present in the heterojunction helps to accelerate electron transfer, thus promoting the production of H2O2. Subsequently, H2O2 is rapidly activated to produce ∙OH due to the synergistic effect of Co and S. Notably, CoS2/CoS/Ti3C2 exhibits enhanced photo-assisted EF (PEF) performance under light. The excellent photocatalysis properties of CoS2/CoS/Ti3C2 are attributed to that the unique hollow microsphere structure of catalyst improves the light absorption, and the uneven charge distribution of CoS2/CoS heterojunctions promotes the separation of photo-generated holes and electrons. Given the above advantages, CoS2/CoS/Ti3C2 cathode delivers a high degradation rate of 98.5%, 91.8%, and 94.5% for SMT, bisphenol A, and sulfadiazine, respectively, with TOC removal efficiency of 76% for SMT with 120 min. This work provides a novel light of the design and construction of efficient PEF cathodes for the treatment of antibiotic wastewater.