Co 2 B and Co Nanoparticles Immobilized on the N-B-Doped Carbon Derived from Nano-B 4 C for Efficient Catalysis of Oxygen Evolution, Hydrogen Evolution, and Oxygen Reduction Reactions

A novel hybrid electrocatalyst of Co B and Co nanoparticles immobilized on N-B-doped carbon derived from nano-B C (Co B/Co/N-B-C/B C) is in situ synthesized by pyrolysis of nano-B C supporting Co(OH) nanoparticles with melamine. The Co B and Co nanoparticles are formed and anchored on the generated N and B codoped carbon and undecomposed B C. The hybrid exhibits remarkable catalytic performances toward the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR)-a very small potential of 1.53 V at 10 mA cm for the OER and a high catalytic kinetics and superior durability for the ORR-which are superior to the RuO and Pt/C catalyst, respectively. Most impressively, the hybrid delivers a very small potential gap of 710 mV, which is lower than those of most bifunctional electrocatalysts reported. In addition, the hybrid also shows a satisfying hydrogen evolution reaction performance offering a small overpotential of 220 mV at 10 mA cm and wonderful stability. The excellent trifunctional catalytic performances issue from synergetic effects of Co B, metal Co, Co/N-doped carbon, and B self-doped carbon coexisting in the hybrid with good interaction mutually. This work provides a new-type efficient multifunctional catalyst for regenerative fuel cell and overall water-splitting technologies.