resumo
A novel composite is prepared by the incorporation of the iron-substituted silicotungstate [SiW11FeIII(H2O)O-39](5) (SiW11Fe) into the 3D structure of MIL-101(Cr). Pyrolytic graphite electrodes are modified with SiW11Fe and the composite material SiW11Fe@MIL-101, and the electrochemical behavior of the electrodes is studied by cyclic voltammetry. The SiW11Fe-modified electrode shows three reduction processes: the peak at more positive potentials is assigned to Fe-III -> FeII and the other two peaks to WVI ! WV processes. The SiW11Fe@ MIL-101-modi-fied electrode shows, besides the redox processes assigned to SiW11Fe, an additional peak from the MIL-101(Cr) matrix, which corresponds to CrIII ! CrII reduction. The SiW11Fe@ MIL-101-modified electrode shows excellent tungsten-based electrocatalytic activity towards nitrite and iodate reduction, and chromium- based electrocatalytic properties towards ascorbic acid oxidation. It, thus, ultimately proves to be a modified electrode with multi-electrocatalytic properties.
palavras-chave
METAL-ORGANIC FRAMEWORKS; ELECTROCHEMICAL PROPERTIES; SUBSTITUTED POLYOXOTUNGSTATES; HETEROGENEOUS CATALYSTS; MODIFIED ELECTRODES; CYCLIC VOLTAMMETRY; KEGGIN STRUCTURE; OXIDATION; REDUCTION; HETEROPOLYTUNGSTATES
categoria
Electrochemistry
autores
Fernandes, DM; Granadeiro, CM; de Sousa, PMP; Grazina, R; Moura, JJG; Silva, P; Paz, FAA; Cunha-Silva, L; Balula, SS; Freire, C
nossos autores
Filipe Alexandre Almeida Paz
Investigador Principal
Patrícia Rodrigues da Silva
Bolseiro de investigaçãoProjectos
agradecimentos
The authors thank Fundacao para a Ciencia e a Tecnologia (FCT, Portugal) for financial support through projects PEst-C/EQB/ LA0006/2011 (to REQUIMTE), FCOMP-01-0124-FEDER-037285, PEst-OE/QUI/UI0612/2013 (to CQB), PEst-C/CTM/LA0011/2013 (to CICECO), PTDC/CTM/100357/2008, PTDC/EQU-EQU/121677/2010, and Operation NORTE-07-0124-FEDER-000067-Nanochemistry, and to the postdoctoral fellowships SFRH/BPD/74877/2010 (D. M. F.) and SFRH/BPD/73191/2010 (C. M. G.). Thanks are also given to COST Action CM-1203 PoCheMoN.