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Exploring the Adsorption Properties of Small Molecules on CeZr-Based Nanoclusters

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Author(s):
Bezerra, Raquel C. ; Calderan, Felipe V. ; Felicio-Sousa, Priscilla ; Peraca, Carina S. T. ; Quiles, Marcos G. ; Da Silva, Juarez L. F.
Total Authors: 6
Document type: Journal article
Source: ACS OMEGA; v. 10, n. 37, p. 14-pg., 2025-09-13.
Abstract

An atomistic understanding of the interactions between the molecules and surfaces is crucial to optimize the catalytic performance in heterogeneous systems. In this investigation, calculations based on density functional theory are used to characterize the adsorption of a set of catalytically motivated molecules (CO, CO2, CH4, NH3, H2O, SO2) on ceria (Ce15O30), zirconia (Zr15O30), and mixed ceria-zirconia (Ce8Zr7O30) nanoclusters, which were selected based on their relevance in a variety of catalytic reactions. To obtain an improved analysis of all optimized adsorbed structures, we developed an automated algorithm to characterize the adsorption modes, covering the orientation and site preferences, based on the combination of Coulomb matrix representations with k-means clustering, using Silhouette scores to define the number of representative structures. From our calculations and analysis, we found that the 6 closest substrate atoms to the adsorbed molecule provide an optimal representation for the characterization of orientation and site preference of the selected molecules. The adsorption modes of CO, CO2, CH4, NH3, H2O, and SO2 were grouped into distinct classes, showing consistent orientation patterns, such as parallel or inclined geometries relative to the substrate. In general, the adsorption process does not induce large deformations in the oxide nanoclusters. In the lowest energy structures, the specific interaction preferences of the molecules with the oxide clusters follow the pattern: CO and NH3 form bonds via lone pairs on the C and N atoms, respectively; CH4 assumes the umbrella configuration; and H2O and SO2 interact through their O atoms. In particular, the SO2 molecule undergoes large changes in the bond angle, indicating a possible deformation toward the SO3 molecule, especially in ceria nanoclusters. With the exception of SO2, all remaining molecules contribute electron density to the substrate upon adsorption, whereas SO2 functions as an electron acceptor (Lewis acid). (AU)

FAPESP's process: 21/03357-3 - Computational study of methane conversion in new products using cerium oxide-based catalysts
Grantee:Carina de Souza Teixeira Peraça
Support Opportunities: Scholarships in Brazil - Doctorate
FAPESP's process: 18/21401-7 - Multi-User Equipment approved in grant 2017/11631-2: cluster computational de alto desempenho - ENIAC
Grantee:Juarez Lopes Ferreira da Silva
Support Opportunities: Multi-user Equipment Program
FAPESP's process: 17/11631-2 - CINE: computational materials design based on atomistic simulations, meso-scale, multi-physics, and artificial intelligence for energy applications
Grantee:Juarez Lopes Ferreira da Silva
Support Opportunities: Research Grants - Applied Research Centers Program
FAPESP's process: 22/09285-7 - Chemical space exploration via semi-supervised learning for design of new materials
Grantee:Marcos Gonçalves Quiles
Support Opportunities: Regular Research Grants