ORIGINAL PAPER Application of nickel phosphate nanoparticles and VSB-5 in the modification of carbon paste electrode for electrocatalytic oxidation of methanol Abdolraouf Samadi-Maybodi & Seyed Karim Hassani Nejad-Darzi & Mohamad Reza Ganjali & Hoda Ilkhani Received: 13 May 2012 / Revised: 4 March 2013 / Accepted: 8 March 2013 # Springer-Verlag Berlin Heidelberg 2013 Abstract Carbon paste electrodes were modified by nickel phosphate nanoparticles and nickel phosphate Versailles Santa Barbara-5 molecular sieves. Then, transition metal ions of Ni (II) were incorporated to the nickel phosphate by immersion of the modified electrode in a 0.1-M nickel chloride solution. The electrochemical behaviors of the modified electrodes were studied using cyclic voltammetry. These modified elec- trodes were used as anode for the electrocatalytic oxidation of methanol in alkaline medium. The influence of some param- eters such as different molecular sieves, scan rate of potential, and methanol concentration was investigated on the anodic peak height of the methanol oxidation. The best result was obtained by nickel phosphate nanoparticles. Keywords Nickel phosphate nanoparticles . VSB-5 . CPE modified electrodes . Methanol oxidation . Alkaline medium Introduction Aluminosilicate zeolites and related nanoporous materials are widely used in the domains of ion exchange, separation, and shape-selective catalysis [1–4]. Open-framework metal phosphate and metal-incorporated aluminophosphate molecu- lar sieves have attracted considerable attention for applications in catalysis, adsorption, separations, etc. [5–8]. Nanoporous nickel phosphates Versailles Santa Barbara-n (VSB-n) attract great benefit, because their configurations are thermo-stable and including transitional metal nickel [9–11]. These materials are used on the basis of catalytic, spectroscopic, magnetic, and electronic properties, which were rarely displayed in traditional zeolites or other porous silicas [9–17]. The structure of VSB-5 contains a hexagonal array composing of 24-member-ring one-dimensional uniform channels with the diameter of 1.2 nm [13–15]. The unit cell formula of VSB-5 is Ni 20 [(OH) 12 (H 2 O) 6 ][(HPO 4 ) 8 (PO 4 ) 4 ]·12H 2 O[13]. Nanostructure materials have generated intense scientific and technological interest over the last few years because of their unique properties and potential applications in areas as diverse as electronics, optics, information storage, bio- medicine, sensors, and product labeling [18]. Recently, nanozeolites have attracted significant attention from re- searchers [19]. The design of modified electrodes for electrocatalysis has been extensively developed because it provides an excellent way to facilitate (accelerate) charge transfer processes [20–22]. This contributes to decrease the overpotentials which is often required to perform electrochemical transformations, as well as to increase the intensity of the corresponding voltammetric responses. Up to now, electrocatalytic studies with mesoporous silica-based materials are only beginning to be explored [23, 24]. Zeolites and nanozeolites have high surface areas with strongly organized microporous channel systems that exhibit an advantage compared to other classical support materials that are of interest for fuel cell technology [25]. They have advantages of ion exchange with the unique molecular sieving properties of the zeolite. Also, zeolite- A. Samadi-Maybodi (*) Analytical Division, Faculty of Chemistry, University of Mazandaran, P.O. Box: 47416–95447, Babolsar, Iran e-mail: samadi@umz.ac.ir S. K. H. Nejad-Darzi Department of Chemistry, Faculty of Science, Babol University of Technology, Babol, Iran M. R. Ganjali : H. Ilkhani Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran, Iran J Solid State Electrochem DOI 10.1007/s10008-013-2059-6