Hollow Nanospheres of Co/N-C Composite as an Efficient Nonprecious Electrocatalyst for Oxygen Reduction Reaction

Hollow nanospheres of Co/N-C composite have been synthesized using silica spheres with solid core and mesoporous shell (SCMS) as hard template and cobalt protoporphyrin as the precursor of C, N and Co by carbonization and etching. With the doping of only 0.68% Co into the hollow composite, activity and selectivity of ORR have been greatly facilitated. Moreover, hollow Co/N-C composite displays good electrochemical durability and tolerance to methanol crossover effect. The excellent catalytic performance of hollow Co/N-C nanospheres towards ORR can be ascribed to their unique hollow structure with mesopores, homogeneously distribution of Co nanoparticles, and suitable doping of N into carbon.