Cobalt-Embedded Nitrogen-Doped Carbon Nanosheets for Oxygen Reduction Reaction under Alkaline and Acidic Media

Abstract

The development of cost-effective oxygen reduction reaction (ORR) catalysts is of great importance and urgency for green energy technologies. Herein, the uniform Co nanoparticles encapsulated in two-dimensional (2D) nitrogen-doped graphiticcarbon nanosheets (Co@N−C) were synthesized by a one-step solvent-free, template-free, and scalable green pyrolysis strategy. Originating from the mutually reinforcing effect between Co nanoparticles and N−C active sites in the stable 2D porous conductive nanosheet structure, the optimized Co@N−C-700 obviously accelerates the catalytic performance for the ORR under both alkaline and acidic conditions. Especially, it showed good performance compared to 20 wt % Pt/C-JM in terms of higher half-wave potential (E 1/2 = 0.86 V), larger current density (J L = 6.1 mA• cm −2 ), and better stability, as well as stronger resistance to methanol crossover. In addition, the 2D Co@N−C-700 still exhibits superior operation performance to commercial Pt/C in a hybrid Zn−air battery test.