www.spm.com.cn Sensors and Actuators B 136 (2009) 464–471 Contents lists available at ScienceDirect Sensors and Actuators B: Chemical journal homepage: www.elsevier.com/locate/snb Nano TiO 2 –Au–KI film sensor for the electrocatalytic oxidation of hydrogen peroxide Soundappan Thiagarajan, Buo-Wei Su, Shen-Ming Chen ∗ Electro analysis and Bioelectrochemistry Laboratory, Department of Chemical Engineering and Biotechnology, National Taipei University of Technology, No.1, Section 3, Chung-Hsiao East Road, Taipei 106, Taiwan, ROC article info Article history: Received 2 August 2008 Received in revised form 1 November 2008 Accepted 10 November 2008 Available online 21 November 2008 Keywords: Nano TiO2 Flower shaped nano Au KI film H2O2 oxidation abstract A glassy carbon and indium tin oxide (ITO) electrodes have been modified with the nano TiO 2 –Au–KI film by the adsorption of TiO 2 nanoparticles on the electrodes followed with the electrochemical deposi- tions of nano Au and KI film. Further the nano TiO 2 –Au–KI film modified ITO was examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. From the microscopic results, the adsorbed nano TiO 2 particles size were found in the range of 70–100nm. Here the electrochemical depositions of nano Au were formed as a flower shape were in the size range of 230 nm to 1 m. Next the electrochemical behavior of nano TiO 2 –Au–KI film has been examined in different pH solutions. The nano TiO 2 –Au–KI film modified glassy carbon electrode (GCE) showed good electrocatalytic activity towards the oxidation of H 2 O 2 in phosphate buffer solutions (pH 7.0). The linear range of detection for H 2 O 2 oxida- tion using nano TiO 2 –Au–KI film was found as 1 × 10 -5 to 1 × 10 -4 M and 1 × 10 -9 to 1 × 10 -7 M in CV and differential pulse voltammetry (DPV) techniques. The practical applications of nano TiO 2 –Au–KI film was evaluated by analyzing the real samples such as antiseptic and contact lens cleaner solutions containing H 2 O 2 . © 2008 Elsevier B.V. All rights reserved. 1. Introduction Hydrogen peroxide has been used as antiseptic and anti- bacterial agent for many years due to its oxidizing effect. It was used by hospitals, doctors, and dentists in sterilizing, cleaning, and treating everything from floors to root canal procedures. Further H 2 O 2 acts as a powerful oxidizing agent, so it could be applied in so many organic compound synthesis reactions [1]. The biological systems will be directly affected by hydrogen peroxide; therefore, the central nervous system diseases could be formed [2]. Accord- ing to these reasons, there is a need of a sensor to detect the H 2 O 2 in clinical and environmental applications [3]. Further the detec- tion and determination of H 2 O 2 can be done in several methods like spectrophotometric [4], titrimetric [5], fluorescence [6], phos- phorescence [7] and chromatographic methods [8]. Although these methods exhibit obvious result for the determination of H 2 O 2, they still have their own technical drawbacks and some of them were quite expensive. Generally in electrochemical analysis, the reduc- tion or oxidation of hydrogen peroxide is not applicable at bare electrodes. At the bare electrode, it shows the slow electrode kinet- ics and high over potential required for this redox reaction. To overcome this problem, the modified electrodes have been widely ∗ Corresponding author. Tel.: +886 2270 17147; fax: +886 2270 25238. E-mail address: smchen78@ms15.hinet.net (S.-M. Chen). applied [9]. Further the modified electrodes have shown interest- ing ability toward hydrogen peroxide detection. But they exhibited with many problems linked to the film deposition process, its tox- icity, poor repeatability, and stability. Also the sensitivity of the modified electrodes was restricted to micro molar concentrations. For these reasons, there is a need to develop a simple and reli- able methods for fabrication of novel sensor for hydrogen peroxide detection at nanomolar or in lower concentration range. The self-assembly method is one of the experimentally sim- plest and cheapest one for the fabrication of nanoparticles from the solution to electrode surface. In self-assembly techniques, the electrostatic adsorption based oppositely charged materials was developed and has been a promising method for the fabrication of thin films [10]. The self-assembled nano particles have been widely used in the modification of surface properties like mate- rials, sensors, microelectronics, and molecular devices [11]. On the other hand, the metal and metal oxide particles in the form of nano size exhibited in higher surface area to reduce the cost and very easily immobilized on electrode surfaces, having their potential applications in the relative biomedical field. Various metal oxide particles have been used for the determination of H 2 O 2 . For exam- ple, nickel oxide [12], iron oxide [13], zirconium oxide [14], tungsten oxide [15], manganese oxide [16], and cobalt oxide [17] have been successfully used for their applications in fabrication of hydro- gen peroxide sensor. Likewise, the titanium oxide nano particles became apparent and fascinating in the electrochemistry field. It 0925-4005/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.snb.2008.11.009