posted on 2022-01-12, 20:33authored byAlice Boudet, Olivier Henrotte, Ndrina Limani, Fatima El Orf, Frédéric Oswald, Bruno Jousselme, Renaud Cornut
In
this article, we set up a methodology to investigate the relationship
between the catalytic activity and the agglomeration state of platinum
group metal-free ORR catalysts. To this end, we have developed a statistical
approach based on scanning electrochemical microscopy (SECM) and atomic
force microscopy (AFM). Two catalysts are investigated at very low
loadings in order to access their intrinsic activity. Differences
in terms of dispersion, stability of the inks, and adherence on the
substrate are observed, highlighting the importance of measuring the
exact amount and agglomeration state of the materials under study.
The agglomeration state of the deposits measured by AFM explains the
differences in activity measured by SECM. The performances of the
catalysts are compared, and the contributions of the intrinsic activity
and the agglomeration state are identified. This work paves the way
toward various applications ranging from the benchmarking of new catalysts
to the optimization of an ink formulation, for ORR and beyond.