Watermelon-like Metallic Co/Graphene-like Nanohybrids from Electrochemical Exfoliation of Anthracite Coal as Superior Oxygen Reduction Reaction Electrocatalyst

摘要

Coal has been employed as both a significant energy supply and resource for the production of modern chemicals and novel carbon materials. Here, we present the synthesis of watermelon-like metallic Co/graphene hybrids with coal as the starting material by approaches of catalytic graphitization, electrochemical exfoliation, and in situ functionalization. The ([BMIm]_(2)[CoCl_(4)]) ion liquid acted as both an electrochemical exfoliation electrolyte and active dopant for the catalyst preparation. It is exhibited that the CoCl~(4–)-based intercalator could be effectively expanded into the gallery region of graphitized coal and resulted in exfoliation of graphene-like nanocarbons. Interestingly, the absorbed Co ligands could be converted into watermelon-like metallic Co encapsulated by 1-butyl-3-methylimidzolium ligand-derived carbons. The electrochemical performance of the [email?protected] catalyst exhibited superior ORR activity to benchmark Pt-C with excellent half-wave potential, higher current density, a direct four-electron pathway, superior methanol tolerance, and stability. This work provides an alternative methodology for the production of graphene-like functional nanocarbons from coal with promising potential in energy conversion applications.