Multiplex Infrared Spectroscopy Imaging for Monitoring Spatially Resolved Redox Chemistry

Autor(es)

Macedo, Lucyano J. A. ^[1] ; Crespilho, Frank N. ^[1]

Afiliação do(s) autor(es)

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

• Tipo de documento: Artigo Científico
• Fonte: Analytical Chemistry; v. 90, n. 3, p. 1487-1491, FEB 6 2018.
• Citações Web of Science: 1

Resumo

IR spectroscopy is an excellent method for understanding surface redox chemistry. However, obtaining sufficient spatial resolution to analyze in situ surface redox reactions is difficult because the aqueous sampling environments provide some challenges for IR spectroscopy. These challenges arise because of the vibrational contribution of water. In this letter, we demonstrate a solution to this problem, where the key development enabling the coupling of spectromicroscopy with electrochemical measurements is a CaF2/electrolyte/Au sandwich IR-sensitive sample holder that acts as an electrochemical cell. In this system, there is a very thin layer of aqueous electrolyte (similar to 10 mu m), and it is possible to monitor, in real time, the vibrational maps and changes to the Au surface modified with iron(II, III) hexacyanoferrate(II, III) by varying the electrochemical potential. By selecting specific vibrational modes with a focal plane array detector, which allows the simultaneous collection of IR spectra from 4096 microscopic regions, chemical maps showing the surface changes were obtained and analyzed using color, providing new insights into how the charge transfer processes affect the chemical composition in specific 2D spatially resolved regions. (AU)

• Processo FAPESP: 13/14262-7 - Filmes nanoestruturados de materiais de interesse biológico
• Beneficiário: Osvaldo Novais de Oliveira Junior
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 15/16672-3 - Desenvolvimento de Bioeletrodos de Alto Desempenho para Miniaturização de Biocélulas a Combustível
• Beneficiário: Frank Nelson Crespilho
• Modalidade de apoio: Auxílio à Pesquisa - Regular