Atomically dispersed Co atoms in nitrogen-doped carbon aerogel for efficient and durable oxygen reduction reaction

Developing non-noble-metal-based electrocatalysts as alternatives to replace Pt-based catalysts for oxygen reduction reaction (ORR) is crucial for large scale industrial application of fuel cells. Herein, we report a facile method to synthesize atomically dispersed Co atoms anchored on nitrogen-doped carbon aerogels with a 3D hierarchically porous network structure via F127-assisted pyrolysis of a phenolic resin/Co2+ composite and subsequent HCl etching treatment. HRTEM, AC-STEM, XRD, XPS, and Raman spectroscopy measurements demonstrate that Co atoms are homogeneously atomically dispersed on nitrogen-doped carbon aerogels within the porous structure by coordination with pyridinic-N. Among a series of samples, the Co-NCA@F127-1: 0.56 catalyst exhibits an enhanced ORR activity with onset potential (Eonset) of 0.935 V vs. RHE, the high diffusion limiting current density of 5.96 mA cm−2 at 0.45 V, as well as an excellent resistance to methanol poisoning and good long-term stability in alkaline medium, comparable to the state-of-the-art Pt/C catalyst. This work may provide a novel and ingenious thought in the design and engineering of efficient and robust electrocatalysts based on single transition-metal atoms supported by nitrogen-doped carbon materials.