CO oxidation as a test reaction for PtGe bimetallic nanoalloys Andoni Ugartemendia 1 , Jose M. Mercero 1 , Abel de Cózar 2,5 , Marko M. Melander 3 , Jaakko Akola 4 and Elisa Jimenez-Izal 1,5 1 Polimero eta Material Aurreratuak: Fisika, Kimika eta Teknologia Saila, Kimika Fakultatea, Euskal Herriko Unibertsitatea (UPV/EHU) and Donostia International Physics Center (DIPC), Spain, 2 Kimika Organikoa I Saila, Kimika Fakultatea, Euskal Herriko Unibertsitatea (UPV/ EHU) and Donostia International Physics Center (DIPC), Spain, 3 Department of Chemistry, Nanoscience Center, University of Jyväskylä, Finland, 4 Department of Physics, Norwegian University of Science and Technology (NTNU), Norway and Computational Physics Laboratory, Tampere University, Finland, 5 IKERBASQUE, Basque Foundation for Science, Spain Bimetallic nanoclusters, also known as nanoalloys, have emerged recently as promising materials with unexpected catalytic properties, where the synergistic effects between the components can lead to enhanced properties as compared to the pure counterparts. 1 In addition, in the size-regime where each atom counts, the size, morphology, alloying concentration, support and adsorption of ligands can drastically modify their properties and thus open a myriad of options in the design of novel catalysts. 2,3 CO oxidation is often used as a probe reaction to model complex catalytic networks. 4 This reaction usually displays bistable kinetics over Pt: 5 at low temperature it suffers from CO poisoning, while at high temperature the adsorption equilibrium of CO changes, becoming more oxygen rich and increasing the reaction rate. Unfortunately, there is still a lack of understanding on the mechanistic details of Pt-based nanoalloys at the atomic level. Herein, we study the catalytic activity of small-size PtGe bimetallic clusters supported on MgO(100), particularly focusing on the effect of alloying concentration. Previously, we have shown that Ge reduces the CO binding energies of PtGe clusters in gas phase, 6,7 so a change of behaviour is expected in the CO oxidation kinetics. Density functional theory (DFT) is employed to i) locate the most stable isomers and adsorption sites by global minima search techniques, 8 ii) assess the stability of the clusters and iii) characterize the energy profiles for the CO oxidation reaction. Finally, the DFT calculations are complemented with microkinetic simulations to thoroughly scrutinized the best reactor conditions. We believe that combining DFT calculations with reliable kinetic models can help screen catalytic materials with optimal activity, selectivity and stability. References 4. H.-J. Freund, G. Meijer, M. Scheffler, R. Schlögl and M. Wolf, Angew. Chem., Int. Ed. , 2011, 50 , 10064–10094. 5. P.-A. Carlsson, M. Skoglundh, P. Thormählen and Bengt Andersson, Topics in Catalysis , 2004, 30 , 375–381. 6. A. Ugartemendia, K. Peeters, P. Ferrari, A. de Cózar, J.M. Mercero, E. Janssens and E. Jimenez-Izal, ChemPhysChem , 2021, 22, 1603–1610. 7. A. Ugartemendia, J.M. Mercero, A. de Cózar and E. Jimenez-Izal, J. Chem. Phys. , 2022, 156 , 174301–174311. 8. H. Zhai and A.N. Alexandrova, J. Chem. Theory Comput. , 2016, 12 , 6213–6226. 1. R. Ferrando, J. Jellinek and R. L. Johnston, Chem. Rev. , 2008, 108 , 845–910. 2. E. Jimenez-Izal and A.N. Alexandrova, Annu. Rev. Phys. Chem. , 2018, 69 , 377–400. 3. L. Liu and A. Corma, Chem. Rev. , 2018, 118 , 4981–5079.
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