Single-source precursor synthesis of nitrogen-doped porous carbon for high-performance electrocatalytic ORR application

Abstract

Simple and efficient synthesis of metal-free nitrogen-doped carbon for electrocatalysts is of great scientific and practical significance. This paper reports a novel method to synthesize nitrogen-doped porous carbon nanomaterials (NPCs) for electrocatalytic oxygen reduction reaction (ORR) application using ferric citrate as the single precursor, involving the pyrolysis of ferric citrate under ammonia and etching the impurities with a HCl aqueous solution. The phase, chemical composition, microstructure and porous texture of the as-obtained NPCs were characterized, and their electrochemical ORR property was investigated. The results verify that the N content and microstructure of the NPCs are adjusted by changing the process parameters in pyrolysis. The typical NPCs has a hierarchical porous structure with a specific surface area of 250 m2 g−1 and a total pore volume of 1.13 cm3 g−1. In ORR test, the NPCs exhibit a low onset potential of −115 mV and their ORR activity is comparable to commercial Pt/C catalysts. In addition, the NPCs are of an excellent property in methanol tolerance. This single-source, simple but robust method to synthesize metal-free NPCs for electrochemical ORR applications paves the possible way towards abundant and environment-friendly electrocatalysts.