Stable Pd-Doped Ceria Structures for CH4 Activation and CO Oxidation

Ya-Qiong Su; Ivo A W Filot; Jin-Xun Liu; Emiel J M Hensen

doi:10.1021/acscatal.7b03295

Stable Pd-Doped Ceria Structures for CH₄ Activation and CO Oxidation

ACS Catal. 2018 Jan 5;8(1):75-80. doi: 10.1021/acscatal.7b03295. Epub 2017 Nov 20.

Authors

Ya-Qiong Su¹, Ivo A W Filot¹, Jin-Xun Liu¹, Emiel J M Hensen¹

Affiliation

¹ Laboratory of Inorganic Materials Chemistry, Schuit Institute of Catalysis, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.

Abstract

Doping CeO₂ with Pd atoms has been associated with catalytic CO oxidation, but current surface models do not allow CO adsorption. Here, we report a new structure of Pd-doped CeO₂(111), in which Pd adopts a square planar configuration instead of the previously assumed octahedral configuration. Oxygen removal from this doped structure is favorable. The resulting defective Pd-doped CeO₂ surface is active for CO oxidation and is also able to cleave the first C-H bond in methane. We show how the moderate CO adsorption energy and dynamic features of the Pd atom upon CO adsorption and CO oxidation contribute to a low-barrier catalytic cycle for CO oxidation. These structures, which are also observed for Ni and Pt, can lead to a more open coordination environment around the doped-transition-metal center. These thermally stable structures are relevant to the development of single-atom catalysts.