Catalytic ativities of single-atom catalysts for CO oxidation: Pt1/FeOx vs. Fe1/FeOx

4 years ago

Catalytic ativities of single-atom catalysts for CO oxidation: Pt1/FeOx vs. Fe1/FeOx

An FeO x -based Pt single-atom catalyst (SAC), Pt1/FeO x , has stimulated significant recent interest owing to its extraordinary activity toward CO oxidation. The concept of SAC has also been successfully extended to other FeO x supported transition metal systems both experimentally and theoretically. However, the FeO x substrate itself (denoted by Fe1/FeO x following the same nomenclature of Pt1/FeO x ) as a typical transition metal oxide possesses a very low catalytic activity toward CO oxidation, although it can be viewed as Fe1/FeO x SAC. Here, to understand the catalytic mechanism of FeO x -based SACs for CO oxidation, we have performed density functional theory calculations on Pt1/FeO x and Fe1/FeO x for CO oxidation to address the differences between these two SACs in terms of the catalytic mechanism of CO oxidation and the chemical behavior of the catalysts. Our calculation results indicated that the catalytic cycle of Fe1/FeO x is much more difficult to accomplish than that of SAC Pt1/FeO x because of a high activation barrier (1.09 eV) for regeneration of the oxygen vacancy formed when the second CO2 molecule desorbs from the surface. Moreover, density of states and Bader charge analysis revealed differences in the catalytic performance for CO oxidation by the SACs Fe1/FeO x and Pt1/FeO x . This work provides insights into the fundamental interactions between the single-atom Pt1 and FeO x substrate, and the exceptional catalytic performance of this system for CO oxidation.

Publisher URL: www.sciencedirect.com/science

DOI: S1872206717628791