SiW11Fe@ MIL-101(Cr) Composite: A Novel and Versatile Electrocatalyst

Abstract

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.