Affiliation:
1. Key Laboratory of Pollution Processes and Environmental Criteria (Ministry of Education) Nankai University Tianjin 300071 P. R. China
2. School of Materials Science and Engineering Georgia Institute of Technology Atlanta GA 30332 USA
3. School of Engineering China Pharmaceutical University Nanjing 210009 P. R. China
4. Department of Chemical and Biomolecular Engineering National University of Singapore Singapore 117585 Singapore
Abstract
AbstractThe past decade has witnessed the great potential of Fe‐based single‐atom electrocatalysis in catalyzing oxygen reduction reaction (ORR). However, it remains a grand challenge to substantially improve their intrinsic activity and long‐term stability in acidic electrolytes. Herein, we report a facile chemical vapor deposition strategy, by which high‐density Fe atoms (3.97 wt%) are coordinated with square‐planar para‐positioned nitrogen and phosphorus atoms in a hierarchical carbon framework. The as‐crafted atomically dispersed Fe catalyst (denoted Fe‐SA/PNC) manifests an outstanding activity towards ORR over the entire pH range. Specifically, the half‐wave potential of 0.92 V, 0.83 V, and 0.86 V vs. reversible hydrogen electrode (RHE) are attained in alkaline, neutral, and acidic electrolytes, respectively, representing the high performance among reported catalysts to date. Furthermore, after 30,000 durability cycles, the Fe‐SA/PNC remains to be stable with no visible performance decay when tested in 0.1 M KOH and 0.5 M H2SO4, and only a minor negative shift of 40 mV detected in 0.1 M HClO4, significantly outperforming commercial Pt/C counterpart. The coordination motif of Fe‐SA/PNC is validated by density functional theory (DFT) calculations. This work provides atomic‐level insight into improving the activity and stability of non‐noble metal ORR catalysts, opening up an avenue to craft the desired single‐atom electrocatalysts.