Honeycomb-like porous carbon with N and S dual-doping as metal-free catalyst for the oxygen reduction reaction

Abstract

It has been a major challenge to dispose the unrenewable high-performance polymers (HPPs) after their large-scale application in our society. Here we report an approach to reuse one kind of HPP as carbon and sulfur sources in synthesizing nitrogen and sulfur dual-doped honeycomb-like porous carbon catalysts for oxygen reduction reaction. Briefly, poly(phenylene sulfide sulfone) with S atoms in polymer chain as sulfur source, dicyandiamide as nitrogen source and SiO2 nanoparticles as hard-template are pyrolyzed in designed temperatures under argon atmosphere. Then N, S dual-doped carbon catalysts (N, S@C) are obtained after subjected etching treatment. By adjusting moderate amount of SiO2, the optimized catalyst (denoted as N, S@CM-1000) pyrolyzed at 1000 °C, shows best ORR electrocatalytic activity in alkaline environment. Impressively, when N, S@CM-1000 is used as a cathode catalyst, the corresponding assembled zinc-air batteries exhibit a maximum power density of 90 mW cm−2 with long-term durability and high rate capacity. Therefore, this work provides a feasible way to resolve and reuse the unrenewable HPP for synthesizing heteroatom doped carbon-based catalysts.