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Identification of Active Sites in a Realistic Model of Strong Metal–Support Interaction Catalysts: The Case of Platinum (1 1 1)‐Supported Iron Oxide Film
Author(s) -
Giordano Livia,
Pacchioni Gianfranco,
Noguera Claudine,
Goniakowski Jacek
Publication year - 2014
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201300642
Subject(s) - oxide , metal , catalysis , platinum , oxygen , adsorption , inorganic chemistry , desorption , iron oxide , materials science , substrate (aquarium) , transition metal , chemistry , chemical engineering , chemical physics , metallurgy , biochemistry , oceanography , organic chemistry , engineering , geology
We report DFT+U results on oxygen adsorption and extraction characteristics obtained for a realistic model of a strong metal–support interaction catalyst, exemplified by a Pt(1 1 1)‐supported FeO x ultra‐thin film. Derived from recent experimental results, the model enables a coherent analysis of the activity towards oxygen at a large variety of sites, which range from FeO and FeO 2 oxide terraces to different oxide–metal and oxide–oxide boundaries. We show that the trends in calculated adsorption and desorption energetics are to a large extent specific to the small thickness of the supported oxides and are mainly driven by electron exchange with the underlying metal substrate. The thorough mapping of the activity of different local surface environments enables the identification of the sites that are most likely responsible for the observed low‐temperature activity of FeO x /Pt films in CO oxidation. Beyond the oxide–metal boundaries known for their higher activity than the separate materials, we find that the sites at boundaries between the coexisting oxide phases of different compositions can easily adsorb and release oxygen.