Adsorption of CO, NO, and H-2 on the Pd(n)Au(55-n )Nanoclusters: A Density Functional Theory Investigation within the van der Waals D3 Corrections

Autor(es)

Batista, Krys E. A. ^[1] ; Da Silva, Juarez L. F. ^[2] ; Piotrowski, Mauricio J. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Pelotas, Dept Phys, POB 354, BR-96010900 Pelotas, RS - Brazil

^[2] Univ Sao Paulo, Sao Carlos Inst Chem, POB 780, BR-13560970 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Physical Chemistry C; v. 123, n. 12, p. 7431-7439, MAR 28 2019.
• Citações Web of Science: 2

Resumo

The PdAu nanoclusters have innumerable potential applications in catalysis, especially because of the changes of the physical and chemical properties as a function of the composition and geometric shape; however, the understanding of the adsorption process is far from satisfactory mainly because of the strong dependence of the adsorption properties on the size, shape, and composition of the nanoclusters. Here, we report a study, based on density functional theory calculations, of the CO, NO, and H-2 molecules adsorbed on PdAu nanoclusters, where we performed a systematic study for bimetallic PdnAu55-n nanoclusters, considering the main energetic, structural, and electronic properties in relation to the composition, and after that, for specific compositions, we performed the adsorption of one molecule (CO, NO, and H-2) on the nanoclusters. We have obtained the lowest energy structures for monometallic and bimetallic nanoclusters, based on the excess energy, where we identified the maximum stability, n = 20, with the Au atoms in the surface region (atoms directly exposed to the vacuum) and Pd atoms in the core region. For the molecular adsorption, we consider Pd-55, Au-55, and Pd20Au35, for which we find that the adsorbed NO systems have higher adsorption energies (in modulus) because of the highest position of the center of gravity of the d-states in relation to the Fermi level. In general, the molecules prefer the top site, with the Pd-molecule bonds being more intense than the Au-molecule bonds. The intermediate adsorption energy values obtained for Pd20Au35 nanoclusters, for CO and NO adsorptions, show the promising Pd-Au combination to build catalysts that are adequate to avoid catalyst poisoning. (AU)

• Processo FAPESP: 17/11631-2 - CINE: desenvolvimento computacional de materiais utilizando simulações atomísticas, meso-escala, multi-física e inteligência artificial para aplicações energéticas
• Beneficiário: Juarez Lopes Ferreira da Silva
• Modalidade de apoio: Auxílio à Pesquisa - Programa Centros de Pesquisa em Engenharia