Towards the Effect of Pt-0/Pt delta+ and Ce3+ Species at the Surface of CeO2 Crystals: Understanding the Nature of the Interactions under CO Oxidation Conditions

Autor(es)

Borges, Lais Reis ^[1] ; da Silva, Anderson Gabriel Marques ^[2] ; Braga, Adriano Henrique ^[1] ; Rossi, Liane Marcia ^[1] ; Suller Garcia, Marco Aurelio ^{[1, 3]} ; Vidinha, Pedro ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Quim, Dept Quim Fundamental, Av Prof Lineu Prestes 748, BR-05508000 Sao Paulo, SP - Brazil

^[2] Pontificia Univ Catolica Rio de Janeiro, Dept Engn Quim & Mat, R Marques Sao Vicente 225, BR-22451900 Rio de Janeiro - Brazil

^[3] Univ Fed Maranhao, Dept Quim, Ave Portugueses 1966, BR-65080805 Sao Luis, Maranhao - Brazil

• Tipo de documento: Artigo Científico
• Fonte: CHEMCATCHEM; v. 13, n. 5 JAN 2021.
• Citações Web of Science: 0

Resumo

We synthesized CeO2 nanowires and nanocubes showing [110]+[100] and [100] surfaces predominantly, respectively, once the different surface energies play a crucial role in the behavior of Ce4+/Ce3+ reversibility. We found out that Pt/CeO2 nanowires presented more Ce3+ content, oxygen vacancies, and atomically dispersed Pt, indicating a stronger Pt-Ce interaction. In contrast, the Pt/CeO2 nanocubes presented a higher contribution of Pt delta+ species, suggesting a well-controlled Pt particle size (similar to 1 nm) and significant interaction with ceria, with oxygen species more available at the surface. Thus, we suggest that the ceria's different surface energies may lead to different Pt distributions of species over the supports. H-2-reduction treatment led to changes in Pt structure that showed a better catalysis performance for the Pt/CeO2 nanowires essentially, supported by XPS and CO-DRIFTS. Nevertheless, this step did not cause improved activity to the point of overcoming the nanocubes-based catalyst, and the reasons were fully discussed. Herein, we propose that catalysts ` performance depends on a complex combination of several materials ` characteristics. These features may lead to different reaction pathways depending on the pre-treatment of the samples. (AU)

• Processo FAPESP: 14/50279-4 - Brasil Research Centre for Gas Innovation
• Beneficiário: Julio Romano Meneghini
• Modalidade de apoio: Auxílio à Pesquisa - Programa Centros de Pesquisa em Engenharia
• Processo FAPESP: 15/14905-0 - Desenvolvimento de membranas (bio)catalíticas para a valorização de CO2
• Beneficiário: Pedro Miguel Vidinha Gomes
• Modalidade de apoio: Auxílio à Pesquisa - Programa BIOEN - Regular