Partial Oxidation of Methanol on Gold: How Selectivity Is Steered by Low-Coordinated Sites

Salma Eltayeb; Lenard L Carroll; Lukas Dippel; Mersad Mostaghimi; Wiebke Riedel; Lyudmila V Moskaleva; Thomas Risse

doi:10.1021/acscatal.3c04578

Partial Oxidation of Methanol on Gold: How Selectivity Is Steered by Low-Coordinated Sites

ACS Catal. 2024 May 6;14(10):7901-7906. doi: 10.1021/acscatal.3c04578. eCollection 2024 May 17.

Authors

Salma Eltayeb¹, Lenard L Carroll², Lukas Dippel¹, Mersad Mostaghimi^{2

3}, Wiebke Riedel¹, Lyudmila V Moskaleva², Thomas Risse¹

Affiliations

¹ Institut für Chemie und Biochemie, Freie Universität Berlin, Arnimallee 22, 14195 Berlin, Germany.
² Department of Chemistry, Faculty of Natural and Agricultural Sciences, University of the Free State, P.O. Box 339, Bloemfontein 9300, South Africa.
³ Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), P.O. Box 3640, 76021 Karlsruhe, Germany.

Abstract

Partial methanol oxidation proceeds with high selectivity to methyl formate (MeFo) on nanoporous gold (npAu) catalysts. As low-coordinated sites on npAu were suggested to affect the selectivity, we experimentally investigated their role in the isothermal selectivity for flat Au(111) and stepped Au(332) model surfaces using a molecular beam approach under well-defined conditions. Direct comparison shows that steps enhance desired MeFo formation and lower undesired overoxidation. DFT calculations reveal differences in oxygen distribution that enhance the barriers to overoxidation at steps. Thus, these results provide an atomic-level understanding of factors controlling the complex reaction network on gold catalysts, such as npAu.