Texturing in situ: N,S-enriched hierarchically porous carbon as a highly active reversible oxygen electrocatalyst†
Facile yet rational design of an efficient reversible oxygen electrocatalyst is critical for many renewable energy conversion and storage technologies. Here we report a simple and general synthetic protocol for fabricating a hierarchically porous and heteroatom doped carbon catalyst, which exhibited outstanding oxygen reduction/evolution activities (with a metric potential difference of 0.72 V in 1 M KOH, the best value for metal-free catalysts reported to date) with good stability in different electrolytes. The excellent performances of the catalyst were primarily endowed by our synthetic protocol, which integrates good conductivity, abundant accessible dopant species and suitable porous architectures within an in situ pyrolysis reaction. As a result, the performances of rechargeable Zn–air batteries based on the optimized catalyst substantially outperform those afforded by a benchmark Pt/C catalyzer. Our work is expected to open up new avenues for developing other efficient catalysts in a facile and viable way.