Effective Proton Concentration as a Descriptor for Local Reaction Environment of Nanoparticle-Based Electrocatalysts

ChemRxiv

Abstract

Electrocatalyst nanoparticles, attached to an electronically conductive support material, are key components determining the performance and lifetime of electrochemical devices like fuel cells and electrolyzers. Differences in intrinsic (electronic) properties between nanoparticle and support induce phenomena subsumed as electro–ionic metal–support interactions. These phenomena are responsible for heterogeneously distributed electron densities and electrical double layer properties along the surface. The resulting local reaction environment, qualitatively different from that of single-crystalline extended surfaces, remains poorly understood. In an effort to address this shortcoming, the current work introduces a novel descriptor for the local reaction environment, namely the effective proton concentration. This descriptor can be obtained theoretically by averaging the proton concentration over the reaction plane around supported nanoparticles. Using gold-supported silver nanoparticles as a model system, we have investigated how the effective proton concentration depends on the size and the density of nanoparticles, Fermi levels of nanoparticle and support materials, bulk electrolyte concentrations, and electrode potential. Results will be discussed in view of the suitability of this effective parameter to be used in the design and optimization of supported nanoparticle-based electrocatalysts for electrochemical applications.

Authors 4

1. Yufan Zhang Aachen

   Forschungszentrum Jülich · RWTH Aachen University

   Affiliation as printed

   Forschungszentrum Jülich

   RWTH Aachen University

2. Tobias Binninger

   Forschungszentrum Jülich

   Affiliation as printed

   Forschungszentrum Jülich

3. Jun Zh. Huang Aachen

   Forschungszentrum Jülich · RWTH Aachen University

   Affiliation as printed

   Forschungszentrum Jülich

   RWTH Aachen University

4. Michael Hermann Eikerling Aachen

   Forschungszentrum Jülich · RWTH Aachen University

   Affiliation as printed

   Forschungszentrum Jülich

   RWTH Aachen University