Irregularities in hydrogen fuel cell catalysts

Armin Hrnjić
Date of publication:
The increasingly evident consequences of climate change are a major motivation for the development of low-carbon technologies, among which fuel cells, using hydrogen as fuel, hold great promise. One of the obstacles to the wider commercialization of the technology is the use of expensive and rare platinum in catalysts, which is why effort goes into trying to reduce the amount of platinum used while preserving the relevant properties of these materials. For the oxygen reduction reaction, one of the reactions in a fuel cell, we use catalysts with alloyed nanoparticles containing platinum and cheaper transition metals. Since certain defects in the nanoparticle structure can occur during the preparation of the catalyst, the effects of all aspects of the structure on the performance in the fuel cell need to be studied in detail.
Researchers from the National Institute of Chemistry, the University of Ljubljana, the Jožef Stefan Institute, and the University of Nova Gorica have investigated the impact of a structural anomaly in hydrogen fuel cell catalysts on their performance. The study confirms that the performance of the investigated catalyst is robust to the presence of certain structural anomalies and thus contributes to a deeper understanding of the structure-property relationships of such functional materials.
For this purpose, the authors of the study prepared platinum-copper-alloy nanoparticles with periodic anti-phase boundaries. These are irregularities in the structure that can occur during thermal annealing, one of the common steps during the preparation of such catalysts. The average distribution of these defects was determined by X-ray powder diffraction, and their occurrence was monitored at different annealing temperatures. The structure was confirmed by other methods and the catalytic performance of the material was measured. It was confirmed that the presence of anti-phase boundaries has no negative effect on the oxygen reduction reaction.
The publication is available in open access at: https://doi.org/10.1016/j.mtnano.2023.100377