Selectively doping pyridinic and pyrrolic nitrogen into a 3D porous carbon matrix through template-induced edge engineering: enhanced catalytic activity towards the oxygen reduction reaction

Abstract

Developing cost-effective and highly efficient oxygen reduction electrocatalysts, such as non-precious metal and metal-free catalysts, is undoubtedly crucial for the commercialization of low-temperature fuel cells. Here, edge-rich nitrogen doped porous carbon catalysts for the oxygen reduction reaction (ORR) with a high proportion of pyridinic and pyrrolic N (up to 94%) were synthesized by an in situ released CO₂ activation method, using glucose and melamine as precursors and nano-CaCO₃ as the template. The catalysts exhibit a three-dimensional structure, hierarchical pores and large pore volumes. Benefiting from the increased active site density and structural advantage, the optimized catalyst shows excellent ORR activity with a half-wave potential of 0.853 V and long-term stability in alkaline media, which is among the best for metal-free catalysts reported to date.