Gallo, I.B.; Carbonio, E.A.; Villullas, H.M.: What Determines Electrochemical Surface Processes on Carbon Supported PdAu Nanoparticles? ACS Catalysis 8 (2018), p. 1818-1827
10.1021/acscatal.7b03734
Open Access Version
Abstract:
Supported bimetallic nanoparticles have good activities in heterogeneous catalysis and electrocatalysts. Among those systems, PdAu shows improved stability and enhanced catalytic activity towards electrochemical reactions such as oxygen reduction, formic acid oxidation and hydrogen evolution. The aim of this work was to study comprehensively the influence of ligand and ensemble effects on surface processes, such as oxide ormation/reduction, oxidation of adsorbed CO and adsorption of hydrogen, taking place on carbon-supported PdAu nanoparticles of different compositions. Towards that end, we thoroughly characterized the properties of PdAu/C catalysts with nominal Au contents of 20 to 50 % (in atoms) prepared by the same procedure and having similar average particle diameters. The combination of results obtained by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) indicates that nanoparticles had Pd-enriched surfaces and Au-rich interior. X-ray absorption spectroscopy (XAS) measurements around the Pd L3 edge evidenced that Au promotes an increase in the electronic occupation of the Pd 4d band, consistent with XPS results.