Sensors and Actuators B 201 (2014) 526–534 Contents lists available at ScienceDirect Sensors and Actuators B: Chemical jo u r nal homep age: www.elsevier.com/locate/snb Facile preparation of MnO 2 nanotubes/reduced graphene oxide nanocomposite for electrochemical sensing of hydrogen peroxide M.R. Mahmoudian a,b,∗ , Y. Alias a , W.J. Basirun a,c , Pei Meng Woi a , M. Sookhakian d a Department of Chemistry, University of Malaya, Kuala Lumpur 50603, Malaysia b Department of Chemistry, Shahid Sherafat, University of Farhangian, 15916 Tehran, Iran c Institute of Nanotechnology & Catalysis Research (NanoCat), Institute of Postgraduate Studies, University Malaya, 50603 Kuala Lumpur, Malaysia d Department of Physics, University of Malaya, Kuala Lumpur 50603, Malaysia a r t i c l e i n f o Article history: Received 20 February 2014 Received in revised form 9 May 2014 Accepted 9 May 2014 Available online 16 May 2014 Keywords: Composite materials Nanostructures Graphene Electrical properties a b s t r a c t We report the synthesis and application of MnO 2 nanotubes/reduced graphene oxide nanocomposite (MnO 2 NTs/RGO NCs) for the detection of hydrogen peroxide. The MnO 2 NTs/RGO NCs were synthesized via a simple single-step hydrothermal process in acidic KMnO 4 solution without the use of surfactants or templates. The nanocomposites were synthesized with different percentages of RGO (1, 3 and 5%). Field emission scanning electron microscopy, transmission electron microscopy and X-ray diffraction results confirmed the growth of MnO 2 NTs on the RGO surface. Electrochemical properties of the MnO 2 NTs/RGO NCs electrode were investigated by amperometry, cyclic voltammetry and electrochemical impedance spectroscopy. The observations confirmed that the charge transfer resistance of the glassy carbon elec- trode (GCE) coated with MnO 2 NTs/RGO NCs was significantly decreased. The limit of detection and limit of quantification (S/N = 3) of two linear segments (0.1–30 mM and 40–80 mM of H 2 O 2 ) are estimated as 1.29 M, 4.29 M and 0.82 M, 2.75 M, respectively. The reproducibility experiment results prove that the use of MnO 2 NTs/RGO NCs is feasible for the quantitative detection of H 2 O 2 in the range of 0.1–80 mmol L -1 . © 2014 Elsevier B.V. All rights reserved. 1. Introduction In recent years, graphene, a single layer of sp 2 hybridized car- bon atoms has attracted great interest in the development of advanced materials. Graphene oxide (GO), a single layer of graphite oxide, was first produced by treating graphite flakes with strong aqueous oxidizing agents [1] and by epitaxial chemical vapor deposition [2]. Numerous applications can be seen for this fan- tastic material in different areas due to its special structure, good solution-processability and ease of post-functionalization of GO. Due to its excellent conductivity, graphene has found applications in the fabrication of electrochemical sensors, capacitors and biosen- sors [3–5]. Recently, inorganic nanoparticles, such as metal [6,7], metal oxide [8,9], metal hydroxide [10] and metal sulfide [11] have been used in the synthesis of new compositions with graphene. The pres- ence of the graphene significantly improves the electrical property ∗ Corresponding author at: Department of Chemistry, University of Malaya, Kuala Lumpur 50603, Malaysia. Tel.: +61 0173928320. E-mail address: M R mahmoudian@yahoo.com (M.R. Mahmoudian). and functionality of the inorganic particles in these composites. Manganese dioxide (MnO 2 ) has been specifically considered for this purpose, due to its low-cost, abundance and non-toxicity compared to other inorganic oxides such as cobalt, nickel and vanadium [12–15]. On the other hand, the detection of H 2 O 2 , ascorbic acid and nitrite ions are few applications of these com- posite electrodes based on MnO 2 -modified carbon powder that were recently reported [16]. H 2 O 2 is one of the most important universal oxidants due to its wide applications in industry and intermediary role in several environmental and biological reactions [17]. Therefore, the effect of shape and type of metal nanoparticle on the nanocomposite performance as a sensor for H 2 O 2 detec- tion is an interesting area of research. Zheng et al. [18] reported a new sandwich structure nanocomposite based on Ag nanopar- ticles supported on MnO 2 modified multiwall carbon nanotubes which were used to fabricate a non-enzymatic H 2 O 2 sensor. The increase of available surface area, which subsequently increases the electrocatalytic activity and promotes electron transfer, was a reason for the high sensitivity of the fabricated non-enzymatic sensor. Liu et al. [19] synthesized manganese dioxide–silver hybrid nanowire and reported enhanced electrochemical signal charac- teristic of silver which can be attributed to the presence of silver http://dx.doi.org/10.1016/j.snb.2014.05.030 0925-4005/© 2014 Elsevier B.V. All rights reserved.