A hybrid-DFT investigation of the Ce oxidation state upon adsorption of F, Na, Ni, Pd and Pt on the (CeO2)(6)cluster

Autor(es)

Ozorio, Mailde S. ^[1] ; Andriani, Karla F. ^[1] ; Da Silva, Juarez L. F. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Sao Carlos Inst Chem, POB 780, BR-13560970 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Physical Chemistry Chemical Physics; v. 22, n. 25, p. 14099-14108, JUL 7 2020.
• Citações Web of Science: 4

Resumo

The formation of small polarons in CeO(2-x)compounds has been investigated mainly on solids, compact surfaces, and large nanoparticles. However, those findings cannot be easily transferred to small ceria clusters, where size effects might play a crucial role. In this work, we report a hybrid density functional theory investigation within the Heyd-Scuseria-Ernzerhof functional to elucidate the response of the Ce oxidation state upon the adsorption of F, Na, Ni, Pd, and Pt on the (CeO2)(6)cluster. Among the selected species, only the Na and Ni adatoms contribute to the formation of a single small-polaron neighboring the Ce(III+)cation (i.e., change from Ce(IV+)to CeIII+) accompanied by a local distortion in the cluster structure, which can be explained by the large magnitude of the charge transfer from the adatoms to the cluster and change in the nature of the Ce f-states (delocalized to localized). The same effect is also obtained by adding a single electron to the (CeO2)(6)cluster. The Pd and Pt adatoms yield only small charge transfer to the (CeO2)(6)cluster, which is not enough to affect the Ce oxidation state. As expected, F binds to the cationic Ce sites and leads to the same effects as obtained by removing a single electron from the cluster, which implies the formation of a localized hole with O p-character above the highest occupied molecular orbital accompanied also by a local structural distortion; however, it does not affect the Ce oxidation state. (AU)

• Processo FAPESP: 18/21401-7 - EMU concedido no processo 2017/11631-2: cluster computacional de alto desempenho - ENIAC
• Beneficiário: Juarez Lopes Ferreira da Silva
• Modalidade de apoio: Auxílio à Pesquisa - Programa Equipamentos Multiusuários
• Processo FAPESP: 18/11152-0 - Desenvolvimento de catalisadores para conversão direta de metano em metanol: uma investigação ab initio utilizando a da Teoria Funcional da Densidade
• Beneficiário: Karla Furtado Andriani
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• 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