Theoretical Studies on the Stability and Reactivity of the Metal-Doped CeO2(100) Surface: Toward H2 Dissociation and Oxygen Vacancy Formation

Wei Zhang; Min Pu; Ming Lei

doi:10.1021/acs.langmuir.0c00644

Theoretical Studies on the Stability and Reactivity of the Metal-Doped CeO₂(100) Surface: Toward H₂ Dissociation and Oxygen Vacancy Formation

Langmuir. 2020 Jun 2;36(21):5891-5901. doi: 10.1021/acs.langmuir.0c00644. Epub 2020 May 19.

Authors

Wei Zhang¹, Min Pu¹, Ming Lei¹

Affiliation

¹ State Key Laboratory of Chemical Resource Engineering, Institute of Computational Chemistry, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, China.

PMID: 32378412
DOI: 10.1021/acs.langmuir.0c00644

Abstract

Surface doping is a common method to improve the performance of nanostructured materials. Different dopants will affect the structure and catalytic reactivity of the support. For a comprehensive understanding of the doping effects of metals doped into CeO₂, we conducted density functional theory (DFT) studies on the stabilities and geometry structures of transition-metal atoms (M = Fe, Co, Ni, Cu; Ru, Rh, Pd, Ag; Os, Ir, Pt, Au) doped into CeO₂(111), (110), and (100) surfaces. Moreover, the reactivity for H₂ dissociation and oxygen vacancy formation are systematically investigated on M-doped CeO₂(100) surfaces. The greater the binding energies of doped M atoms on the CeO₂ surface, the more difficult the formation of oxygen vacancies. The doped Co and Ir atoms do not directly participate in H₂ activation but serve as a promoter to make the H-H bond to break easily. The Cu, Ru, Pd, Ag, Pt, and Au atoms could act as the catalytically active center for H₂ dissociation and greatly reduce the activation energy barrier. Besides, it is easier to generate H₂O (W^M) and a surface oxygen vacancy from the intermediate H2^M/H4^M than from H3^M/H5^M, which is related to the acid-base interaction between H_Ce/M* and H_O* in H2^M/H4^M. This work could provide theoretical insights into the atomic structure characteristics of the transition-metal-doped CeO₂(100) surface and give ideas for the design of hydrogenation catalysts.