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O: Fachverband Oberflächenphysik

O 20: Poster Session II: Heterogeneous catalysis II

O 20.2: Poster

Montag, 1. März 2021, 13:30–15:30, P

Microscopy of Gold Oxide Formation on TiO₂/Au(111) Model Catalysts for CO Oxidation — •Sabine Wenzel and Irene M. N. Groot — Leiden Institute of Chemistry, The Netherlands

Hydrogen produced from methanol has to be cleaned from traces of CO for its use in fuel cells [1]. Gold-based catalysts have been shown to selectively oxidize CO in H₂ environment at low temperatures [2]. There is ample evidence for strong interactions between gold and typically used supports such as TiO₂ [3]. However, the exact oxidation state of the active phase of gold as well as the role of oxide supports and water remain under debate [4,5,6]. Our set-up [7] allows for the controlled preparation and characterization of model catalyst surfaces in ultra-high vacuum combined with scanning tunneling microscopy at atmospheric pressures. A TiO₂/Au(111) model catalyst was prepared via physical vapor deposition and exposed to CO oxidation reaction conditions. We present evidence for the formation of a surface gold oxide in this environment. Our findings suggest that transfer of atomic oxygen from the titania nanoparticles to the gold substrate does not occur but that contaminants can promote the oxidation of gold.

References: [1] Dhar et al., J. Electrochem. Soc. 1987, 134, 12, 3021 [2] Haruta, The Chemical Record 2003, 3, 75 [3] Palomina et al., ACS Sustainable Chem. Eng. 2017, 5, 10783 [4] Min et al., Chem. Rev. 2007, 107, 2709 [5] Klyushin et al., ACS Catal. 2016 6 , 3372 [6] Kettemann et al., ACS Catal. 2017, 7, 8247 [7] Herbschleb et al., Rev. Sci. Instrum. 2014, 85, 083703