Tuning the Co active sites in Co/ZnNC for improving oxygen reduction reaction

The M N C (M = non-noble metal) materials have been utilized as highly active and cost-efficient catalysts for boosting the ponderous kinetics of oxygen reduction reaction (ORR). However, the fabrication and tailoring of bi-active sites in M N C catalysts are essential for ORR. In this investigation, the N -doped porous carbon supported Co– and Zn- based nanoparticles (Co/Zn N C) catalyst was synthesized by carbonizing the composite of ZIF-8 and cobalt phthalocyanine. By tailoring the numbers of active sites in Co/Zn N C, the catalyst achieved a maximum half-wave potential ( E 1/2 ) of 0.846 V ( vs RHE ) and a highest limiting current density of 5.4 mA cm −2 in alkaline medium. After 20,000 cyclic voltammetry cycles, the E 1/2 shift of Co/Zn N C has been only shifted about 30 mV, outperforming commercial Pt/C catalysts (126 mV). Density Functional Theory calculations reveal that the cooperative interaction between adjacent Zn and Co active sites enhances the adsorption of ORR intermediates, thus boosting the overall reaction kinetics. This investigation offers a novel strategy for the construction of highly active and cost-effective metal catalysts as well as tailoring the numbers of active sites for ORR.