Electronic Structure Studies and Photocatalytic Properties of Cubic Bi1.5ZnNb1.5O7

Ganchimeg Perenlei,Peter C Talbot,Jose A Alarco,Wayde N Martens

doi:10.1155/2015/575376

Ganchimeg Perenlei, Peter C Talbot + Show 2 more

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https://doi.org/10.1155/2015/575376

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Abstract

The photocatalytic ability of cubic Bi1.5ZnNb1.5O7(BZN) pyrochlore for the decolorization of an acid orange 7 (AO7) azo dye in aqueous solution under ultraviolet (UV) irradiation has been investigated for the first time. BZN catalyst powders prepared using low temperature sol-gel and higher temperature solid-state methods have been evaluated and their reaction rates have been compared. The experimental band gap energy has been estimated from the optical absorption edge and has been used as reference for theoretical calculations. The electronic band structure of BZN has been investigated using first-principles density functional theory (DFT) calculations for random, completely and partially ordered solid solutions of Zn cations in both theAandBsites of the pyrochlore structure. The nature of the orbitals in the valence band (VB) and the conduction band (CB) has been identified and the theoretical band gap energy has been discussed in terms of the DFT model approximations.

Highlights

The textile industry is one of the biggest consumers of synthetic dyes which comprise a large number of chemicals, mostly organic compounds [1]
The main crystal peaks in the patterns are indexed to Bi1.5ZnNb1.5O7 (JCPDS PDF, 04-016-3002) in the Inorganic Crystal Structure Database (ICSD) database, which indicates that the cubic BZN compounds are obtained at both sintering temperatures
The assumption of a random solid solution of Zn may give a reasonable explanation for the X-ray and neutron diffraction properties of cubic BZN structure, density functional theory (DFT) calculations indicate that, to obtain band gaps in the electronic band structure, some degree of partial order in the substitution is required

Summary

Introduction

The textile industry is one of the biggest consumers of synthetic dyes which comprise a large number of chemicals, mostly organic compounds [1]. International Journal of Photoenergy better than BiNbO4/BiTaO4 [13] and Bi2MoO6/Bi2WoO6 [14], respectively Another type of materials with mixed atoms, such as Bi2MNbO7 (M=Al, Ga, In, Fe) [15, 16] and Bi2MTaO7 (M=Al, Ga, In, Fe) [17, 18], has been studied for photocatalytic removal of organic dye pollutants from water. These compounds have ideal pyrochlore structure with A2B2O7 general composition and generally exhibit diverse physical properties, which are useful for a wide range of applications [19, 20]. Particular focus has been paid on the assumptions concerning the substitutions and the effects of these on the size and nature of the band gaps

Experimental Procedure

Theoretical Calculations

Results and Discussion

Conclusions