Electrolytic core–shell Co@C for diethyl phthalate degradation

Greenhouse gases carbon dioxide (CO2) can be converted into high value-added carbon materials by molten salt electrolysis. Herein, we employ CO2 as the inorganic carbon source to prepare a core–shell catalyst ([email protected]) by molten salt electrolysis for the activation of peroxymonosulfate (PMS) to degrade diethyl phthalate (DEP). The electrolytic [email protected] catalyst presents a high catalytic performance for the degradation of DEP with a high turnover frequency (TOF) value (2.28 min−1), a relatively low catalyst dosage (Cat = 50 mg L–1), low oxidant concentration (PMS = 0.46 mM), a wide range of pH applicability (pH = 3–9), and low activation energy (Ea = 38.88 kJ mol−1). In addition, the Co leaching rate is low (<1 mg L–1) in the pH range of 5–11 and the total organic carbon (TOC) removal was reached 78.9% under the catalyst dosage was 50 mg L–1. The DEP degradation pathways mainly involved ethyl formate elimination, ethoxy abstraction, carboxyl abstraction, decarboxylation, hydroxy abstraction, esterification and ring cleavage of DEP. Further, theoretical calculations confirm that Co nanoparticles (Co NPs) encapsulated with graphitized carbon shell derived from CO2 reduce the work function (WF) of catalysts, enhance the length of bond O–O (IO-O) of PMS molecule, and facilitate the charge transfer from the catalysts to PMS molecule. This work provides a new insight into the utilization of CO2 served as inorganic carbon sources and the design of heterogeneous catalysts.