Atomic Fe Dispersed on N-Doped Carbon Hollow Nanospheres for High-Efficiency Electrocatalytic Oxygen Reduction

Exploration of high-efficiency, economical, and ultrastable electrocatalysts for the oxygen reduction reaction (ORR) to substitute precious Pt is of great significance in electrochemical energy conversion devices. Single-atom catalysts (SACs) have sparked tremendous interest for their maximum atom-utilization efficiency and fascinating properties. Therefore, the development of effective synthetic methodology toward SACs becomes highly imperative yet still remains greatly challenging. Herein, a reliable SiO2-templated strategy is elaborately designed to synthesize atomically dispersed Fe atoms anchored on N-doped carbon nanospheres (denoted as Fe-N-C HNSs) using the cheap and sustainable biomaterial of histidine (His) as the N and C precursor. By virtue of the numerous atomically dispersed Fe-N-4 moieties and unique spherical hollow architecture, the as-fabricated Fe-N-C HNSs exhibit excellent ORR performance in alkaline medium with outstanding activity, high long-term stability, and superior tolerance to methanol crossover, exceeding the commercial Pt/C catalyst and most previously reported non-precious-metal catalysts. This present synthetic strategy will provide new inspiration to the fabrication of various high-efficiency single-atom catalysts for diverse applications.