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O: Fachverband Oberflächenphysik
O 7: Heterogeneous Catalysis: Experiment
O 7.6: Vortrag
Montag, 12. März 2018, 11:45–12:00, MA 141
Segregation Phenomena in Size-Selected Bimetallic CuNi Nanoparticle Catalysts — •Lukas Pielsticker1, Ioannis Zegkinoglou1, Nuria J. Divins1, and Beatriz Roldan Cuenya1,2 — 1Department of Physics, Ruhr University Bochum — 2Department of Interface Science, Fritz-Haber Institute of the Max Planck Society
Catalytic systems based on bimetallic alloy nanoparticles (NPs) often exhibit significantly superior catalytic properties compared to their monometallic counterparts. The spatial atomic distribution in such bimetallic nanocatalysts plays a pivotal role in their efficiency and stability. Employing near-ambient pressure (NAP-XPS) and ultrahigh vacuum X-ray photoelectron spectroscopy (XPS) together with atomic force microscopy (AFM), surface segregation, restructuring, and sintering phenomena in size-controlled CuNi NPs supported on SiO2/Si substrates were systematically investigated as a function of temperature, chemical state, and reactive gas environment [1]. The depth profile of the elemental composition of the particles was determined under operando CO2 hydrogenation conditions by varying the X-ray photon energy. The morphological changes induced by adding CO to the reaction mixture were investigated. Our study showed that the initial chemical state of the NPs and the adsorbate-induced effects sensitively affect restructuring in CuNi nanocatalysts, suggesting that their surface atomic composition and thus their catalytic properties can be tuned by appropriate plasma and annealing treatments.
[1] Pielsticker et al., J. Phys. Chem. B, Just Accepted Manuscript (2017), DOI: 10.1021/acs.jpcb.7b06984.