Cobalt Oxide-Supported Pt Electrocatalysts: Intimate Correlation between Particle Size, Electronic Metal–Support Interaction and Stability

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Abstract
Oxide supports can modify and stabilize platinum nanoparticles (NPs) in electrocatalytic materials. We studied related phenomena on model systems consisting of Pt NPs on atomically-defined Co3O4(111) thin films. Chemical states and dissolution behavior of model catalysts were investigated as a function of the particle size and the electrochemical potential by ex situ emersion synchrotron radiation photoelectron spectroscopy and by online inductively coupled plasma mass spectrometry. Electronic metal-support interaction (EMSI) yields partially oxidized Ptδ+ species at the metal/support interface of metallic nanometer-sized Pt NPs. In contrast, sub-nanometer particles form Ptδ+ aggregates which are exclusively accompanied by subsurface Pt4+ species. Dissolution of Cox+ ions is strongly coupled to the presence of Ptδ+ and the reduction of subsurface Pt4+ species. Our findings suggest that EMSI directly affects the integrity of oxide-based electrocatalysts and may be employed to stabilize Pt NPs against sintering and dissolution.
Funding Information
  • Bundesministerium f?r Bildung und Forschung (05K19WE1)
  • Deutsche Forschungsgemeinschaft (214951840, 322419553, 431733372, CH 1763/5-1, EXC 315, FOR 1878)
  • Grantov? Agentura Cesk? Republiky (20-11688J, GACR 20-11688J)
  • Czech Ministry of Education (LM2018116)
  • CERIC-ERIC consortium
  • Bayerisches Staatsministerium f?r Wirtschaft, Landesentwicklung und Energie
  • Grant Agency of the Charles University (262120)
  • Helmholtz Institute Erlangen-N?rnberg for Renewable Energy