Premium
Mechanism of CO Oxidation on Pd/CeO 2 (100): The Unique Surface‐Structure of CeO 2 (100) and the Role of Peroxide
Author(s) -
Kim Yongseon,
Lee Hosik,
Kwak Ja Hun
Publication year - 2020
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.202000714
Subject(s) - zigzag , catalysis , adsorption , density functional theory , raman spectroscopy , chemistry , oxygen , peroxide , reaction mechanism , crystallography , inorganic chemistry , computational chemistry , organic chemistry , physics , geometry , mathematics , optics
Understanding the atomic mechanism of low‐temperature CO oxidation on a heterogeneous catalyst is challenging. We performed density functional theory (DFT) calculations to identify the surface structure and reaction mechanism responsible for low‐temperature CO oxidation on Pd/CeO 2 (100) surfaces. DFT calculations reveal the formation of a unique zigzag chain structure by the oxygen and Ce atoms of the topmost surface of CeO 2 (100) with Pd atoms located between the zigzag chains. O 2 adsorbed on such Pd atoms is stable in the presence of CO but plays a very important role in lowering the activation barrier for low‐temperature CO oxidation by forming a square‐planar PdO 4 structure and facilitating further O 2 adsorption. In‐situ Raman spectroscopy studies confirm the adsorbed oxygen species to be peroxides. The calculated activation barrier for CO oxidation, based on the mechanism suggested by these unique structures and peroxides, is 31.2 kJ/mol, in excellent agreement with our experimental results.