Short Communication Template synthesis of zinc oxide nanoparticles entrapped in the zeolite Y matrix and applying them for thermal control paint Zeinab Fereshteh a , Mohammad Reza Loghman-Estarki a,b,n , Reza Shoja Razavi b , Mehrdad Taheran c a Department of Material Engineering, Isfahan University of Technology, Isfahan, 84154-83111, Iran b Department of Material Engineering, Malek Ashtar University of Technology, Shahinshahr, Isfahan, Iran c Department of Chemical Engineering, Faculty of Engineering, University of Isfahan, Isfahan, Iran article info Available online 20 November 2012 Keywords: Zeolite Y ZnO nanoparticles Nanocomposite Nanopigment Nanopaint White Thermal Control Paint abstract Zinc oxide nanoparticles within faujasite zeolites have been synthesized by a procedure comprising of (i) ion-exchange of zinc ions into the zeolite, (ii) precipitation of zinc ions with sodium hydroxide within the supercage of the zeolite, and (iii) calcination. The products were characterized by XRD, SEM, TEM, EDX and FTIR techniques. The size of the ZnO particles was in the range of 24 74 nm. Finally, ZnO@zeolite was used as a pigment and its optical properties were studied. & 2012 Elsevier Ltd. All rights reserved. 1. Introduction There is a sizeable body of published research con- centrating on semiconducting nanomaterials as these demonstrate significant quantum size effects (QSE) [1]. Optical and electrical properties of these materials can be tuned by the size of semiconductor material [1,2]. Thus particles size should be controlled for particular applications. Various preparative methods have been explored to produce nanosized particles. These methods include the control of particle growth by employing matrices or stabilizers such as thiols, glasses, polymers, reverse micelles, zeolites, xerogels, etc. Zeolite matrices of microporous materials have been used to support nanosized clusters of ZnO [3]. In general, zeolites are three-dimensional microporous crystalline solids with well-defined aluminosilicates struc- tures [4]. Diversity in pore size, shape, topology, and frame- work composition provides zeolites a rich variety of interesting properties and industrial applications such as catalysts, ion exchangers, and adsorbents [5]. Their frameworks, being typically anionic, may contain linked cages, cavities or channels. Guest cation can populate the pores to maintain its electrical neutrality and participate in ion-exchange processes with other types of metals when it is in aqueous solution [4]. So far, some attempts have been made to make nanosized clusters, semiconductors, polymers, catalysts [6–11] in zeolite pores. In the present work, we have used zeolite Y as a template for synthesizing ZnO nanoparticles. Zinc oxide is a wide band-gap II–VI semiconductor (band-gap¼ 3.37 eV, 298 K) and shows significant QSE when quantum dots approach the Bohr radius, ca. 1.8 nm [7]. These properties make ZnO an excellent candidate for applications such as photodetectors [8], solar cells [9], nanolasers [10], gas sensors [11,12], and structural ceramics [13]. Finally, we also survey optical properties of ZnO@zeolite as a pigment via UV–visible diffusion reflectance (DRS) spectroscopy. 2. Experimental 2.1. Materials Zinc (II) acetate (99%), sodium hydroxide (99%) and sodium zeolite-Y (Si/Al ¼ 2.5 and pore size 1.8 nm) and zeolite A were purchased from Sigma-Aldrich. All chemicals Contents lists available at SciVerse ScienceDirect journal homepage: www.elsevier.com/locate/mssp Materials Science in Semiconductor Processing 1369-8001/$ - see front matter & 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.mssp.2012.08.005 n Corresponding author at: Department of Material Engineering, Isfahan University of Technology, Isfahan, 84154-83111, Iran. E-mail addresses: mrloghman@ma.iut.ac.ir, loghman57@gmail.com (M.R. Loghman-Estarki). Materials Science in Semiconductor Processing 16 (2013) 547–553