Regensburg 2019 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 20: Poster Monday: Electronic Structure

O 20.6: Poster

Montag, 1. April 2019, 17:45–20:00, Poster F

CO Oxidation by noble metal single atom catalysts on transition metal doped oxides — •Debolina Misra and Satyesh Yadav — Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai, India

Stability of transition metal (TM) defects in BaO and MgO have been studied using density functional theory. Our defect formation energy calculations show that TM atoms at various charge states can be stabilized not only at the substitutional sites, but some of them can also be accommodated well in the tetrahedral voids available in the oxides. We use this result to solve the problem of binding noble metal atoms in heterogeneous catalysis by proposing a new and effective way to anchor them on the support material. Single atoms of Pt, Pd and Au are considered on TM (Nb, Mo) doped BaO {001} surface for CO oxidation. Both hollow (H) and O-top (O) positions of the oxide surface are considered as the possible binding sites for the metal atoms. Our results reveal that compared to bare BaO {001} surface, noble metals bind more strongly when the surface is doped by Nb or Mo. For example, binding energy of Au changes from -1.28 eV (H) and -1.85 eV (O) in BaO {001}, to (i) -3.61 eV (H) and -3.69 eV (O) in Nb-doped, and (ii) -3.57 eV (H) and -3.70 eV (O) in Mo-doped {001} surface. This is attributed to the charge transfer between TM dopants and the noble metal atoms. Our calculated adsorption energies of CO molecule on the noble metal atoms are comparable to other catalytically active systems. We further calculate the minimum energy pathway and the reaction barriers for all the elementary steps of CO oxidation.