Life cycle of single atom catalysts: a Mössbauer study on degradation and reactivation of tetrapyrrolic Fe–N–C powders†‡
Abstract
The degradation of a single-site atomically dispersed, model Fe–N–C powder catalyst with high activity is investigated using cryo-Mössbauer spectroscopy. The results indicate a degradation initiated by an Fe2+ to Fe3+ oxidation due to coordination of oxygen to tetrapyrrolic Fe–N4 sites at atmospheric conditions (change between characteristic doublets) before iron(III) oxide is formed (sextet). Thermal reactivation can be used to restore substantial catalytic activity of aged Fe–N–C powders.
- This article is part of the themed collection: New horizons in materials for energy conversion, optics and electronics