Sensors and Actuators B 173 (2012) 72–78 Contents lists available at SciVerse ScienceDirect Sensors and Actuators B: Chemical j o ur nal homep a ge: www.elsevier.com/locate/snb Ce-doped ZnO nanorods for the detection of hazardous chemical G.N. Dar a,b,c , Ahmad Umar b,d,∗ , S.A. Zaidi b,d , Ahmed A. Ibrahim d , M. Abaker a,b,c , S. Baskoutas c , M.S. Al-Assiri a,b a Department of Physics, Faculty of Sciences and Arts, Najran University, P.O. Box 1988, Najran 11001, Saudi Arabia b Promising Centre for Sensors and Electronic Devices (PCSED), Najran University, P.O. Box 1988, Najran 11001, Saudi Arabia c Department of Materials Science, University of Patras, Rio Patras GR-26504, Greece d Department of Chemistry, Faculty of Sciences and Arts, Najran University, P.O. Box 1988, Najran 11001, Saudi Arabia a r t i c l e i n f o Article history: Received 26 April 2012 Received in revised form 27 May 2012 Accepted 2 June 2012 Available online 9 June 2012 Keywords: Ce-doped ZnO nanorods Structural and compositional properties Hydroquinone Chemical sensor a b s t r a c t This paper reports a successful synthesis, characterizations and an efficient chemical sensor application of as-synthesized Ce-doped ZnO nanorods. The Ce-doped ZnO nanorods were synthesized by simple low-temperature hydrothermal process. The as-synthesized nanorods were characterized in terms of their morphological, structural and compositional properties. The morphological and structural studies revealed that the synthesized nanorods were grown in high-density and possessed well-crystallinity. The as-synthesized nanorods were used as an effective electron mediator for the fabrication of an effi- cient hydroquinone chemical sensor. The fabricated sensor exhibited high and reproducible sensitivity of ∼10.218 ± 0.01 mA cm -2 mM -1 and detection limit of ∼10 nM. To the best of our knowledge, this is the first ever report on the fabrication of hydroquinone chemical sensor using Ce-doped ZnO nanostruc- tures. This work demonstrates that simply synthesized Ce-doped ZnO nanostructures can be used as an effective electron mediator for the fabrication of chemical sensors. © 2012 Elsevier B.V. All rights reserved. 1. Introduction The detection of analytes using modified electrodes has always been the focus of the various researchers over a decade. The modification of electrodes brings numerous advantages for the determination of different chemicals such as improved electro- catalysis reactions, prevention of undesirable surface reactions and untoward fouling effects of electrodes. The ever increasing need of various simple, cost effective, rapid and reproducible analytical techniques for the determination of hazardous and toxic chemicals has pushed the scientific community to search new and more effec- tive materials which could be utilized to fabricate the simple and sensitive sensors. In recent years, the environmental pollution has increased greatly due to the toxic chemicals as reacting species in most of the industries, vast use of fertilizers in agriculture sector, combustion from automobiles and so on [1,2]. Hydroquinone, a phenolic compound, is used in various manufacturing units such as paper industries, coal-tar production, and photographic devel- oping areas. It is one of the highly hazardous polluting chemical, ∗ Corresponding author at: Promising Centre for Sensors and Electronic Devices (PCSED), Najran University, P.O. Box 1988, Najran 11001, Saudi Arabia. Tel.: +966 534574597. E-mail address: ahmadumar786@gmail.com (A. Umar). usually absorbed through the skin and mucous membranes and can cause damage to the lungs, liver, kidney and urinary tract in the living beings [3–5]. Furthermore, hydroquinone is consid- ered to be a potential carcinogen candidate and as an effective xenobiotic micro-pollutant. The environmental monitoring agen- cies have tightened the norms in order to prevent or reduce the pollution caused by it. In this context, it becomes highly desir- able to detect and quantify the leakage of hydroquinone to avoid untoward effects on human health. After exhaustive literature sur- vey, few reports concerning the hydroquinone sensors were found such as Hathoot et al. used poly 1,8-diaminonaphtalene derivatives modified electrodes for electrocatalytic oxidation of hydroquinone [5], while in another report, Wang et al. prepared a self-assembled gold monolayers modified electrode (l-Cys/Au SAMs) of l-cysteine and performed voltammetric sensing of hydroquinone [6]. A biomimetic sensor based on dinuclear copper (II) complex com- bined with a ligand was used to determine the hydroquinone in cosmetics using square wave voltammetry by de Oliveira et al. [7]. Kong et al. synthesized a composite of -cyclodextrin/poly(N- acetylaniline)/carbon nanotube modified glassy carbon electrode (GCE) and conducted voltammetric determination of hydroquinone [8]. In a very recent report, a hybrid material composed of graphene was synthesized by Li et al. using microwave-assisted chemi- cal reduction process and used for electrochemical detection of hydroquinone [9]. All the mentioned reports presented satisfactory results for the evaluation of hydroquinone, however, the discussed 0925-4005/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.snb.2012.06.001