High catalytic activity of indium tin oxide nanoparticle modified electrode towards electro-oxidation of ascorbic acid

Abstract

a b s t r a c tMetal nanoparticles and carbon nanotubes have been shown to possess high electrocatalytic activity. Indium tin oxide (ITO) is a popular electrode material, but the electro-catalytic properties of its nanomaterials have not been reported. We demonstrate here for the first time facile electrocatalytic oxidation of ascorbic acid on ITO nanoparticle-modified electrodes. Compared to the conventional ITO thin film electrode, the voltammetric peak potential for ascorbic acid oxidation was lowered by 800 mV on ITO nanoparticle-modified electrodes to a potential similar to metal electrodes. The ITO nanoparticle was composed of 90% In 2 O 3 and 10% SnO 2 . Since the electrocatalytic activity was also found on In 2 O 3 nanoparticle electrodes but not on SnO 2 nanoparticle electrodes, the In 2 O 3 composition in ITO nanoparticle is mainly responsible for the high activity. In photoluminescence measurement, two intense emission peaks at 415 nm and 438 nm associated with surface oxygen vacancies were observed on the semiconductor electrodes. It was hypothesized that the oxygen vacancies could be the active sites for electrocatalytic reactions. A linear relationship between the oxidation current and ascorbic acid concentration was found in the range of 10 lM to 5 mM, with a lower detection limit of 5 lM and 7.9% RSD (n = 11). The high electro-catalytic activity and transmittance of In 2 O 3 and ITO nanoparticle electrodes make them potentially very useful in opto-electronic devices and chemical/bio-sensors.

Preparation of Indium Tin Oxide Nanoparticle‐modified 3‐Aminopropyltrimethoxysilane‐functionalized Indium Tin Oxide Electrode for Electrochemical Sulfide Detection

“…Higher catalytic activity of ITONP‐modified ITO can be attributed to the higher active catalytic sites than that of the bare ITO and also might be the oxygen vacancy defects on In 2 O 3 of ITONPs. Both causes are speculated for high catalytic properties of ITONP‐modified ITO for ascorbic acid electro‐oxidation by Wei et al earlier .…”

“…However, these modified electrodes may not be stable enough for fabricating a sulfide sensor due to poisoning of electrode surface from sulfide, as discussed in an earlier paragraph for their corresponding bulk electrodes. Recently, in an investigation by Wei et al., an ITONP‐modified ITO electrode displayed better electrocatalytic properties toward ascorbic acid and dopamine than did the ITO bulk electrode . Wei et al.…”

“…However, these modified electrodes may not be stable enough for fabricating a sulfide sensor due to poisoning of electrode surface from sulfide, as discussed in an earlier paragraph for their corresponding bulk electrodes. Recently, in an investigation by Wei et al, an ITONPmodified ITO electrode displayed better electrocatalytic properties toward ascorbic acid and dopamine than did the ITO bulk electrode [31]. Wei et al prepared the ITONP-modified ITO electrode by spin coating a mixture of ITONPs and Tween-20 and successive annealing at 450 8 C. Ideally, this high temperature annealing should be eliminated for process simplification and reduction of the sensor cost [31].Generally, the preparation of the nanomaterials modified electrodes for sulfide sensor are complex and least cost effective as it required to use potential, and too long preparation steps including preprocessing of nanomaterials in harsh condition [4,[32][33][34][35][36].…”

“…Recently, in an investigation by Wei et al, an ITONPmodified ITO electrode displayed better electrocatalytic properties toward ascorbic acid and dopamine than did the ITO bulk electrode [31]. Wei et al prepared the ITONP-modified ITO electrode by spin coating a mixture of ITONPs and Tween-20 and successive annealing at 450 8 C. Ideally, this high temperature annealing should be eliminated for process simplification and reduction of the sensor cost [31].Generally, the preparation of the nanomaterials modified electrodes for sulfide sensor are complex and least cost effective as it required to use potential, and too long preparation steps including preprocessing of nanomaterials in harsh condition [4,[32][33][34][35][36]. Although, some nanomaterial-modified electrodes have been reported for the detection of sulfides due to their good electrocatalytic properties [4,17,[32][33][34][35][36], the fabrication of sulfide sensors using the ITONP-modified ITO, which is prepared at low temperature (40 8C) without preprocessing of commercially available ITONP, has not been reported.…”

Gas phase fabrication of morphology-controlled ITO nanoparticles and their assembled conductive films

“…Facile electrocatalytic oxidation of tripropyl amine (TPA) and ascorbic acid on ITO nanoparticle modified electrodes was found. 11 Due to their wide bandgaps and low resistivities, ITO nanoparticles are known as promising gas-sensitive materials. 12,13 Flexible strain sensors were fabricated based on patterned ITO nanoparticle channels.…”