Electrochimica Acta 55 (2010) 6885–6891 Contents lists available at ScienceDirect Electrochimica Acta journal homepage: www.elsevier.com/locate/electacta Controlled synthesis and methanol sensing capabilities of Pt-incorporated ZnO nanospheres Mashkoor Ahmad, Lin Gan, Caofeng Pan, Jing Zhu ∗ Beijing National Center for Electron Microscopy, The State Key Laboratory of New Ceramics and Fine Processing, Laboratory of Advanced Material, Department of Material Science and Engineering, Tsinghua University, Beijing 100084, China article info Article history: Received 21 March 2010 Received in revised form 17 May 2010 Accepted 25 May 2010 Available online 4 June 2010 Keywords: ZnO Platinum Hybrid nanospheres Methanol oxidation Electrodeposition abstract Platinum nanoparticles incorporated ZnO hybrid nanospheres (PtZONS) have been synthesized via elec- trodeposition which is easy to control over the size distribution range. The Pt nanoparticles in ZnO nanospheres have been identified with high-resolution transmission electron microscopy (HRTEM) and energy dispersive spectroscopy (EDS). Methanol sensing capabilities of the nanospheres have been inves- tigated through electrochemical measurements. The electrochemical measurements prove that these nanospheres demonstrate the abilities to electrocatalyze the oxidation of methanol and substantially raise the response current. The sensitivity of the Nafion/PtZONS/glassy carbon modified electrode to methanol is 235.47 AM -1 cm -2 , which is much higher than that of a pure ZnO and Pt nanospheres mod- ified electrodes. Furthermore, it has been revealed that the electrode exhibits a good anti-interference and long-term stability. Our investigation demonstrates that the Pt–ZnO nanospheres can be employed for various applications. © 2010 Elsevier Ltd. All rights reserved. 1. Introduction Nanocrystal-based hybrid nanostructures have received great research attention because they may provide enhanced catalytic, photochemical/physical and thermal stability properties superior to a single system [1–3]. Furthermore, hybrid nanostructures are usually multifunctional [4,5]. Hybrid semiconducting nanostruc- tures are currently a research focus owing to their potential in optoelectronics, drugs delivery, environmental monitoring, con- trol of chemical processes and biomedical diagnosis applications [6,7]. These advantages make hybrid nanostructures one of the most promising candidates for the exploration of new applica- tions. Among the noble metals, Platinum has found widespread use in a range of applications due to its unique physical and chem- ical properties [8–10]. It is also very attractive in that it can be introduced into ZnO lattice and is predicted to serve as a stable electron donor to the conduction band of ZnO [11]. Various methods have been developed for the synthesis of hybrid nanospheres with tunable size and controllable compositions [12,13]. Among differ- ent methods electrodeposition is considered an effective approach for the synthesis of hybrid nanostructures at room temperature with very simple and well-controlled manner. ZnO is a transpar- ent oxide semiconductor that possesses piezoelectric properties, ∗ Corresponding author. Fax: +86 10 62771160. E-mail address: jzhu@mail.tsinghua.edu.cn (J. Zhu). which has been widely used for solar cells [14], optoelectronics devices [15] and electromechanical coupled sensors and transduc- ers [16]. Moreover, ZnO is biocompatible and can be directly used for biomedical applications [17,18]. However, it is well known to be difficult to grow the two materials together in a controlled manner due to lattice mismatch and a large difference in their surface free energies. In spite of many successful demonstrations, it remains a grand challenge to produce large quantities of noble metals-ZnO hybrid nanostructure, together with well-controlled dimensions and morphologies. Recently, many researchers have reported the inclusion of Pt into ZnO to enhance the electrocat- alytic activity of the nanostructures, which is crucial for their practical applications (Ref. [11]). In our previous work, we have been successfully synthesized the PtZONS and repotted the highly sensitive amperometric cholesterol biosensor based on these nanospheres. It has been found that the combination of ZnO and Pt nanoparticles facilitates the low potential amperometric detection of cholesterol and enhances the anti-interference abil- ity of the biosensor. Also, it has been revealed that ZnO improves the electrocatalytic activity of Pt nanoparticles, which in turn enhances the sensitivity of the biosensor for cholesterol detection [19]. On the other hand, methanol is one of the most widely used organic solvents, especially in industrial and household products. It is also potentially valuable as an alternative automobile fuel [20]. However, methanol exposure via inhalation and skin absorp- tion may lead to toxic effects from headaches to blindness with 0013-4686/$ – see front matter © 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.electacta.2010.05.075