Space-Confined Synthesis of Lasagna-Like N-Doped Graphene-Wrapped Copper-Cobalt Sulfides as Efficient and Durable Electrocatalysts for Oxygen Reduction and Oxygen Evolution Reactions

Searching for efficient and economical bifunctional oxygen electrocatalyst is urgent for exploring the sustainable energy technologies. Herein, the unique lasagna-like structured copper-cobalt sulfides wrapped by N-doped reduced graphene oxide (CuCoS/N-rGO) were first fabricated through in-situ controllable growth of bimetallic MOFs (CuCo-BTC) on GO followed by further pyrolysis and sulfuration. The interconnected structure was formed because the bimetal ions and carboxyl groups in CuCo-BTC precursor combines with the functional groups (-COOH, -OH, etc.) on the surface of GO to interconnect the graphene sheets to avoid agglomeration of subsequent pyrolysis. In turn, the carbonized graphene was used as a space-constrained reactor to wrap CuCoS particles to prevent the aggregation, and the electronic distribution changed between them to produce excellent synergistic effect. In the exploration of the molar ratios of bimetallic ions, the optimal CuCoS-4/N-rGO with nCo: nCu of 4:1 possessed unique structure, l...