Publications by authors named "Arnaud Viola"

Designing electrocatalysts with optimal activity and selectivity relies on a thorough understanding of the surface structure under reaction conditions. In this study, experimental and computational approaches are combined to elucidate reconstruction processes on low-index Pd surfaces during H-insertion following proton electroreduction. While electrochemical scanning tunneling microscopy clearly reveals pronounced surface roughening and morphological changes on Pd(111), Pd(110), and Pd(100) surfaces during cyclic voltammetry, a complementary analysis using inductively coupled plasma mass spectrometry excludes Pd dissolution as the primary cause of the observed restructuring.

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Article Synopsis
  • Surface strain is a key factor in gas phase catalysis and electrocatalysis, affecting how adsorbates bind to catalysts.
  • Researchers used advanced techniques at the European Synchrotron Radiation Facility to study strain in individual platinum nanoparticles while controlling their electrochemical environment.
  • Findings revealed a complex strain distribution in the nanoparticles that varies with their structure, which can help in designing better nanocatalysts for energy applications.
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Unsupported nanoparticles are now recognized as model catalysts to evaluate the intrinsic activity of metal particles, irrespectively of that of the support. Co nanoparticles with different morphologies, rods, diabolos and cubes have been prepared by the polyol process and tested for the acceptorless catalytic dehydrogenation of alcohols under solvent-free conditions. Rods crystallize with the pure hcp structure, diabolos with a mixture of hcp and fcc phases, while the cubes crystallize in a complex mixture of hcp, fcc and ε-Co phases.

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Article Synopsis
  • The one-step seed-mediated synthesis method is popular for creating ferromagnetic metal nanoparticles due to its ability to control particle shape, but it has limited mechanistic studies.
  • This research focuses on the heteronucleation process during the synthesis of cobalt nanoparticles in liquid polyols, using high-resolution imaging and hydrogen evolution measurements to track nucleation and growth.
  • The study reveals that iridium and ruthenium seeds play a crucial role in the nucleation, and their influence on cobalt's microstructure varies, showcasing the relationship between the nucleating agent and particle formation.
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