Regensburg 2016 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 31: Heterogeneous Catalysis: Theory

O 31.8: Vortrag

Dienstag, 8. März 2016, 12:15–12:30, S053

Formic acid dehydrogenation over Au/CeO₂ catalysts: Theoretical DFT study — •Jan Kučera and Axel Gross — Institute of Theoretical Chemistry, Ulm University, D-89069 Ulm/Germany

Heterogeneous catalysts based on nano-sized Au supported on various oxides (e.g., TiO₂,CeO₂, or SiO₂) can selectively decompose formic acid (FA) to provide pure hydrogen already at low temperatures - a process of high technological relevance in the context of hydrogen technology as part of a sustainable energy concept. Despite of the activity ascribed to Au, the decomposition mechanism depends strongly on the nature of the oxide. Unfortunately, the mechanistic understanding of the function of the support remains unclear, which hampers to establish a route towards better catalysts.

Our computational study focuses on the elucidation of elementary processes behind the FA decomposition over Au/CeO₂. In particular, the reducible surface of CeO₂ facilitates the dynamical formation of catalytically active subnanometer/atomic Au species detached from Au-nanoparticles [1]. We have employed periodic DFT+U models together with a periodic embedded cluster method (PEECM) to investigate the dehydrogenation process of FA over single-Au species on CeO₂. We will discuss the influence of the charge transfer between Au and the CeO₂ support on the catalytic mechanism in the presence of various surface defects.

[1] N. Yi et al., ChemSusChem 6, 816 (2013) 816; Y-G. Wang et al., Nat. Commun. 6, 6511 (2015).