In-situ gas foaming synthesis of N, S-rich co-doped hierarchically ordered porous carbon as an efficient oxygen reduction reaction catalyst

Abstract

The design and manufacture of cost-effective and efficient oxygen reduction reaction (ORR) catalysts is critical to the widespread application of multiple energy conversion devices. Herein, a combination of in-situ gas foaming and the hard template method is proposed to construct the N, S-rich co-doped hierarchically ordered porous carbon (NSHOPC) as an effective metal-free electrocatalyst for ORR via carbonizing a mixture of polyallyl thiourea (PATU) and thiourea in silica colloidal crystal template (SiO2-CCT) voids. Benefiting from the hierarchically ordered porous (HOP) architectures and the mass doping of N and S, NSHOPC displays excellent ORR activities (the half-wave potential of 0.889 V in 0.1 M KOH and 0.786 V in 0.5 M H2SO4) and long-term stability, which are all better than those of Pt/C. As the air cathode in a Zn-air battery (ZAB), NSHOPC exhibits a high peak power density of 174.6 mW·cm−2 and long-term discharge stability. The remarkable performance of the as-synthesized NSHOPC signifies broad prospects for actual applications in energy conversion devices.