One-Pot Synthesis of Fe-N-Containing Carbon Aerogel for Oxygen Reduction Reaction

Three-dimensional Fe-N-C aerogel catalysts for the oxygen reduction reaction (ORR) are prepared with resorcinol-formaldehyde-melamine and iron precursor using one-pot sol-gel process followed by supercritical drying and heat treatment in nitrogen (N-2) and then ammonia (NH3) atmospheres. We studied the effect of the synthesis conditions (Fe precursor and Fe content) of organic aerogel and the heat treatment parameters (including temperature and duration) under N-2/NH3 atmosphere on the structural properties and ORR catalytic activities of the resulting Fe-N-C aerogel catalysts. The Fe-N-C aerogel catalysts were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and N-2-adsorption/desorption, and the ORR activities were studied by the rotating disk electrode method. It was found that the pore structure, the chemical composition, and ultimately the ORR performance were largely affected by the nature of iron precursor, iron content, and the conditions of heat treatment. The catalysts using Iron (III) acetylacetonate as Fe precursor incorporated with 3 wt% of Fe followed by the HT at 800 degrees C for 1 h under N-2 and then 950 degrees C under NH3 for 30 min showed the highest content of active site (Fe-N-x) and largest mesopore volume, resulting in an enhanced catalytic activity and mass-transport property.

Automated summary

The synthesis conditions and heat treatment parameters of Fe-N-C aerogel catalysts significantly influence their structural properties and ORR catalytic activities, suggesting that appropriate synthesis methods and heat treatment conditions can enhance catalytic performance.