Iron-Nitrogen-Carbon Aerogel for Enhanced Oxygen Reduction in Acidic Media: The Influence of Temperature

Abstract

The oxygen reduction reaction (ORR) in an acidic environment is crucial for fuel cell technology. Understanding its complex kinetics and developing advanced catalyst materials have the potential to drive significant improvements in energy efficiency, paving the way for sustainable, green energy solutions. In this work, Iron-Nitrogen-Carbon@aerogel (Fe(FcP)_x-N-C@Aerogel) catalysts are developed by carbonizing polypyrrole (PPy) and ferrocene. The ORR performance of these catalysts is investigated across different annealing temperatures. The catalysts’ shape and structure are validated through scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), revealing that changes in annealing temperature affect morphology and nitrogen-containing functional groups of the catalyst. Linear sweep voltammetry (LSV) and rotating disk electrode (RDE) studies demonstrated that Fe(FcP)₈₀₀-N-C@Aerogel catalysts exhibit excellent performance, with a half-wave potential of 0.687 V and an average electron transfer number of 3.98 under acidic conditions. These findings suggest a near-four-electron reaction pathway, highlighting the catalyst's strong ORR activity, high efficiency, and durability, with only 17.4 mV LSV curve decay after 10,000 cycles. In conclusion, Fe(FcP)_x-N-C@Aerogel advances ORR catalysis in acidic media by delivering exceptional performance and durability, driven by its innovative architecture and precisely engineered active sites, setting a new benchmark for high-efficiency energy conversion.