B, N-doped carbon nanosheets embedded with Co nanoparticles for enhanced oxygen reduction reaction

Co-based materials with optimized adsorption energy of reaction intermediates have become the promising electrocatalyst for enhanced oxygen reduction reaction (ORR). Here, B, N-doped carbon nanosheets embedded with Co nanoparticles are reported by a simple wet chemical method and further pyrolysis process. The average size of Co nanoparticles is 10.03 +/- 1.6 nm. X-ray photoelectron spectroscopy and electrochemical measurements show that those doped with B enrich active sites of the catalyst with highly active B-C bond and provide greater electrochemical surface area for ORR. The material shows impressive ORR performance with a positive half-wave potential of 0.87 V and a superior limiting current density of 6.88 mA cm(-2) outperforming commercial Pt/C in alkaline solution. Noticeably, the optimized electron structure of Co-N species significantly weakens the Co-O bond and adsorption energy of OOH*, which could promote the occurrence of close to the four-electron ORR process. This work, besides showing electrocatalysts with excellent ORR performance, provided an approach for optimizing catalytic activity of Co-based materials.