Bottom-up synthesis of MOF-derived hollow N-doped carbon materials for enhanced ORR performance

Abstract

The search on low-cost, ultra-stable, and high-performance non-novel metal replacements to the Pt-based catalysts for oxygen reduction reaction (ORR) is of great urgency. Herein, a bottom-up method has been proposed to synthesize unique hollow N-doped carbon spheres (HNCSs) from an initial amorphous coordination polymer (CP) template-assisted route for the first time. HNCSs exhibit competitively comparable high electrocatalytic ORR activity, excellent reaction selectivity, and stronger long-term stability and negligible methanol crossover effect compared to the commercial Pt/C under the alkaline medium. Together with the other two reported carbonaceous ORR catalysts, including SCSs and NGPCs, our HNCSs possess the lowest Tafel slope of 65.7 mV dec−1 which is close to Pt/C (62.6 mV dec−1), and show much enhanced ORR activity (JL = 5.34 mA cm−2) and stability (Retention = 96.5%, Time = 10 h). This CP-templated route for hollow carbon materials will shed light on a new synthetic strategy to prepare high-performance carbon-based and/or metal-free ORR catalysts.