Abstract

FORERO, Andrés et al. Theoretical study of the CO Oxidation with O₂ using Au-Pd and Au-Pt catalysts. Rev.Colomb.Quim. [online]. 2022, vol.51, n.1, pp.48-57.  Epub Oct 26, 2022. ISSN 0120-2804.  https://doi.org/10.15446/rev.colomb.quim.v51n1.101015.

In the current study were development calculations based on Density Functional Theory (DFT) with the B3PW91/LANL2DZ approach for optimizing both monometallic and bimetallic systems: Au9, AusPd, Au8Pt, AuPds, AuPts, Pd9 y Pt9. Such materials were theoretically tested as catalyst for the oxidation of carbon monoxide (CO) and the most favorable system for its further adsorption was determined. The substitution of Pt and Pd by Au atoms in the nonamers generated a change in the tridimensional structure of the system. The global reactivity analysis showed that the most reactive cluster is Pt9 followed by AuPts. On the other hand, the Fukui indexes identified the most susceptible sites for a nucleophilic attack of both clusters. The CO adsorption generated an oxidation cascade which liberated ∼ 4.5 eV, indicating that the reaction is highly exothermic and exergonic. Both AuPt8 and Pt9 showed the lowest values of activation energy in the determining step of the mechanism. In general, the substitution of a Pt (Pd) atom by an Au atom does not affect the reactivity of the nonamers and then it is inferred that the AuPds cluster could be a promissory catalyst in the CO oxidation.

Keywords : Bimetallic clusters; selective oxidation of CO; reactivity indexes; adsorption.

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