Electrochemical Studies and Sensing of Iodate, Periodate and Sulphite Ions at Carbon Nanotubes/ Prussian Blue Films Modified Platinum Electrode

摘要

This work describes the modification of platinum electrode with and without functionalised multi- 2- walled carbon nanotubes (MWCNT-SO3 ) and prussian blue nanoparticles (PB) for the detection ofiodate, periodate and sulphite ions. The modified electrodes were characterised using techniques suchas transmission electron microscopy (TEM), electron dispersive X-ray spectroscopy (EDX), cyclicvoltammetry (CVs) and electrochemical impedance spectroscopy (EIS). The Pt-MWCNT-PB electrodeexhibited enhanced electron transport and catalytic efficiency towards the electrocatalysis of iodate- - 2- (IO3 ), periodate (IO4 ) and sulphite (SO3 ) compared to the other electrodes studied. The electrodewas characterised by some level of adsorption due to adsorbed intermediates. The degree of adsorption-1 was quantified as indicated by the Tafel values of 211.0, 176.2, and 129.2 mVdec for iodate,periodate and sulphite respectively. The analytes were detected at micromolar level. The limit of6 3 -1 -1 6detection and the catalytic rate constant were 8.30 M (1.37x10 cm mol s ), 8.06 M (0.34x10 3 -1 -1 7 3 -1 -1 cm mol s ) and 4.70 M (5.24 x 10 cm mol s ) for iodate, periodate and sulphite. The electrodedetects iodate in the presence of the interfering effect from other oxo-anions. This electrode can bereliably used to assay iodate in real or commercial salt composition.