Correlating structural dynamics and catalytic activity of AgAu nanoparticles with ultrafast spectroscopy and all-atom molecular dynamics simulations

Autor(es)

Ferbonink, G. F. ^[1] ; Rodrigues, T. S. ^[2] ; dos Santos, D. P. ^[1] ; Camargo, P. H. C. ^[2] ; Albuquerque, R. Q. ^[3] ; Nome, R. A. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas UNICAMP, Inst Quim, Campinas, SP - Brazil

^[2] Univ Sao Paulo, Inst Quim, Dept Quim Fundamental, Ave Prof Lineu Prestes 748, BR-05508000 Sao Paulo, SP - Brazil

^[3] Liverpool John Moores Univ, Sch Pharm & Biomol Sci, Liverpool, Merseyside - England

• Tipo de documento: Artigo Científico
• Fonte: FARADAY DISCUSSIONS; v. 208, p. 269-286, AUG 1 2018.
• Citações Web of Science: 0

Resumo

In this study, we investigated hollow AgAu nanoparticles with the goal of improving our understanding of the composition-dependent catalytic activity of these nanoparticles. AgAu nanoparticles were synthesized via the galvanic replacement method with controlled size and nanoparticle compositions. We studied extinction spectra with UV-Vis spectroscopy and simulations based on Mie theory and the boundary element method, and ultrafast spectroscopy measurements to characterize decay constants and the overall energy transfer dynamics as a function of AgAu composition. Electron-phonon coupling times for each composition were obtained from pump-power dependent pump-probe transients. These spectroscopic studies showed how nanoscale surface segregation, hollow interiors and porosity affect the surface plasmon resonance wavelength and fundamental electron-phonon coupling times. Analysis of the spectroscopic data was used to correlate electron-phonon coupling times to AgAu composition, and thus to surface segregation and catalytic activity. We have performed all-atom molecular dynamics simulations of model hollow AgAu core-shell nanoparticles to characterize nanoparticle stability and equilibrium structures, besides providing atomic level views of nanoparticle surface segregation. Overall, the basic atomistic and electron-lattice dynamics of core-shell AgAu nanoparticles characterized here thus aid the mechanistic understanding and performance optimization of AgAu nanoparticle catalysts. (AU)

• Processo FAPESP: 15/21366-9 - Materiais híbridos contendo nanopartículas metálicas para aplicações catalíticas
• Beneficiário: Pedro Henrique Cury Camargo
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 15/26308-7 - Otimização das propriedades físico-químicas de materiais nano-estruturados e suas aplicações em reconhecimento molecular, catálise e conversão/armazenamento de energia
• Beneficiário: Roberto Manuel Torresi
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 16/23430-9 - Explorando a dinâmica estocástica de nanomateriais
• Beneficiário: René Alfonso Nome Silva
• Modalidade de apoio: Auxílio à Pesquisa - Regular