Dependence Properties of Sol-Gel Derived CuO@SiO2 Nanostructure to Diverse Concentrations of Copper Oxide

V Homaunmir,S H Tohidi,G Grigorya,M Ayatollah Zada Shirazi

doi:10.1155/2013/156813

Abstract

Various concentrations of copper oxide were embedded into silica matrix of xerogel forms using copper source Cu(NO3)2·3H2O. The xerogel samples were prepared by hydrolysis and condensation of tetraethyl orthosilicate (TEOS) with determination of new molar ratios of the components by the sol-gel method. In this paper, three samples of copper oxide were doped into silica matrices using different concentrations. We obtained 10, 20, and 30 wt.% of copper oxide in silica matrices labeled as A, B, and C, respectively. The absorption and transmittance spectra of the gel matrices were treated at different concentrations by Uv-vis spectrophotometer. Quantities of water and transparency in the silica network change the spectral characteristics of Cu2+ ions in the host silica. Absorption spectra of the samples heated to higher concentration complete the conversion of Cu2+ ions to Cu+ ions. The effects of concentration of copper oxide were characterized by X-ray diffraction (XRD) patterns, and the transmission electron microscope (TEM) micrographs. Also, textural properties of samples were studied by surface area analysis (BET method) at different concentrations.

Highlights

Sol-gel processing is a relatively new technique in the preparation of glasses and primarily to get potentially high purity and homogeneity as well as low processing temperatures compared with the traditional glass melting techniques [1]
Comparison of surface area, porosity, density, and pore volumes for these samples and obtained results show that A sample is the best material for catalytic activity [22]
The transmittance spectra of high temperature treated copper ions doped into silica matrices indicate that the broad bond with filtering effect

Summary

Introduction

Sol-gel processing is a relatively new technique in the preparation of glasses and primarily to get potentially high purity and homogeneity as well as low processing temperatures compared with the traditional glass melting techniques [1]. Hydrolysis and polycondensation of alkoxide precursors followed by aging and drying are of the best methods used for making sol-gel of silica monolith [2]. Introducing transition metals into hydrolysable precursors through sol-gel method permits the formation of numerous novel materials that exhibit important optical and/or catalytic properties [3, 4]. Mohanan and Brock [6] have studied copper oxide silica aerogel composites by varying pH values, copper precursor salts, and treatment temperatures. They found that based-catalyzed gels underwent a gradual change from bonded Cu+2 ions to segregated copper oxide at different heating conditions. The aim of present work is understanding the effect of concentration on the spectroscopic properties of different copper concentrations (10, 20, and 30 wt.%)

Methods

Results

Conclusion