Spectrochimica Acta Part A 86 (2012) 271–275 Contents lists available at SciVerse ScienceDirect Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy j ourna l ho me page: www.elsevier.com/locate/saa As-synthesis of nanostructure AgCl/Ag/MCM-41 composite Sh. Sohrabnezhad a,∗ , A. Pourahmad b a Department of Chemistry, Faculty of Science, University of Guilan, P.O. Box 1914, Rasht, Iran b Department of Chemistry, Faculty of Science, Rasht Branch, Islamic Azad University, Rasht, Iran a r t i c l e i n f o Article history: Received 3 August 2011 Received in revised form 5 October 2011 Accepted 14 October 2011 Keywords: Heterogeneous catalysis Nanostructure Silver nanoparticles Plasmonic resonance Photocatalysis a b s t r a c t In this work, we present the simple synthetic route for silver chloride/silver nanoparticles (AgCl/Ag- NPs) using as-synthesis method. The structure, composition and optical properties of such material were investigated by transmission electron microscopy (TEM), UV–visible diffuse reflectance spectroscopy (UV–vis DRS), X-ray diffraction (XRD) and FTIR. Powder X-ray diffraction showed that when AgNO 3 con- tent is below 0.1 wt.% in synthetic gel, the guest AgCl/Ag-NPs is formed on the silica channel wall, and lower exists in the crystalline state. When AgNO 3 content exceeds this value, AgCl/Ag nanoparticles can be observed in high crystalline state. The absorption at 327 nm ascribed to the characteristic absorp- tion of the AgCl semiconductor. Ag nanoparticles have been shown to exist in the nanocomposite at 375 nm. When AgNO 3 content is above 0.1 wt.% in synthetic gel, spectra exhibited stronger absorption at 450–700 nm that was attributed to the surface plasmonic resonance of silver nanoparticles. The obtained AgCl/Ag/MCM-41 sample exhibit enhanced photocatalytic activity for the degradation of methylene blue under visible-light irradiation. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Silver chloride AgCl has a direct band gap of 5.6 eV and an indirect band gap of 3.25 eV [1]. However, silver halides are photosensitive materials extensively used as source materials in photographic films. On absorbing a photon, a silver halide particle generates an electron and a hole, and subsequently the photo- generated electron combines with an Ag + ion to form an Ag 0 atom. Ultimately, a cluster of silver atoms is formed within a sil- ver halide particle upon repeated absorption of photons. Despite its photosensitivity, AgCl can be made a stable and efficient pho- tocatalyst under ultraviolet and visible light if photo-generated electrons are prevented from combining with Ag + ions and if photo-generated holes are combined with Cl - ions to form Cl 0 atoms. These requirements are met by a new photocatalyst Ag/AgCl, in which silver nanoparticles are formed on the surface of AgCl powder particles [2,3]. An alternative way of meeting the requirements is to prepare a composite semiconductor sys- tem in which AgCl particles are formed on support materials with high surface area such as mesoporous materials and zeolites [4–6]. The development of visible-light-driven photocatalysts has been an attractive research field due to ambitions of water ∗ Corresponding author. Tel.: +98 451 551 7137; fax: +98 451 551 4701. E-mail address: sohrabnezhad@guilan.ac.ir (Sh. Sohrabnezhad). splitting, pollutant destruction, and bacterial disinfection [7–10]. Most research has been concentrated on anatase (TiO 2 ), which is photostable, nontoxic, cheap, and active. Due to its large band gap of 3.2 eV, UV light (I < 400 nm) is necessary to generate the electron–hole pairs, thus restricting its absorption of solar energy. Thus, several attempts have been made to overcome this barrier, including phase and morphological control, doping, surface sensi- tization, composite photocatalysts, heterojunction photocatalyts, and plasmonic photocatalysts [11–13]. Among them, the plasmonic photocatalysts are one of the most promising approaches because of their outstanding performance in photocatalytic processes. The plasmonic photocatalyst combines the plasmon resonance of noble-metal nanoparticles with a semiconductor catalyst. Noble- metal nanoparticles show strong visible-light absorption because of size- and shape-dependent plasmon resonance, which acceler- ates the separation process of the photogenerated electrons and holes in the semiconductor catalyst [14–16]. Herein, we present the simple synthetic route for silver chlo- ride/silver nanoparticles (AgCl/Ag-NPs) using as-synthesis method. From the controlled amount of adding AgNO 3, silver nanoparticles with surface plasmonic resonance were successfully synthe- sized and size-dependent photocatalytic activity was explored in the decomposition of organic dye molecule under visible light. In addition, the detailed formations of silverchloride/silver nanoparticles into the MCM-41 were scrutinized using diffraction pattern, transmission electron microscopy, and diffuse reflectance spectroscopy. 1386-1425/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.saa.2011.10.035