Reactive Template-Derived CoFe/N-Doped Carbon Nanosheets as Highly Efficient Electrocatalysts toward Oxygen Reduction, Oxygen Evolution, and Hydrogen Evolution

The increasing need for clean and sustainable energy inspires researchers to explore low-cost nonprecious metal electrocatalysts for advanced energy storage and conversion. Herein, we develop a reactive template route to fabricate a high-efficiency oxygen reduction reaction (ORR)/oxygen evolution reaction (OER)/hydrogen evolution reaction (HER) trifunctional electrocatalyst (CoFe/NH-C NS) via pyrolyzing the mixture containing CoFe-layered double hydroxide@glucosaminoglycan (CoFe-LDH@p-Glu) and urea/dicyandiamide. In this strategy, the CoFe-LDH not only provides a well-defined two-dimensional template to form carbon NSs but also employs a well-distributed CoFe precursor to form uniform CoFe nanoparticles (NPs). Such a synthetic strategy has been demonstrated effective to controllably fabricate the special nanostructure with metal NPs embedded in N-doped carbon NSs and favorable exposure of active sites, leading to a strong synergistic effect between CoFe and N-doped carbon NSs and abundant electrocatalytic active sites for energy electrocatalysis. CoFe/NH-C NS exhibits superior ORR performances to Pt/C with more positive half-wave potential (844 mV for CoFe/NH-C NS vs 832 mV for Pt/C), longer stability, and better methanol tolerance in alkaline conditions. Furthermore, CoFe/NH-C NS displays an identical current density to commercial RuO2 at 1.8 V (vs RHE) toward OER and a remarkable electrocatalytic property toward HER in alkaline conditions. This work presents fresh strategies for the design and fabrication of high-performance carbon-based energy materials.