Comparative Studies on Structural, Optical, and Textural Properties of Combustion Derived ZnO Prepared Using Various Fuels and Their Photocatalytic Activity

Pure mesoporous nanosized ZnO samples have been synthesized by combustion synthesis method using different type of fuels such as citric acid, dextrose, glycine, oxalyl dihydrazide, oxalic acid, and urea. All these samples were found to have the standard hexagonal wurtzite structure with the lattice constants <i>a</i> and <i>c</i> having values 3.25 Å and 5.21 Å, respectively. The diffuse reflectance spectra of the prepared samples have shown the maximum absorption of light in the UV region stating that these catalysts can be used as photocatalysts. The BET surface area measurements of the prepared catalysts were found to vary according to the equivalence ratio. The presence of pronounced hysteresis in N₂ adsorption–desorption isotherm curves indicated the three-dimensional network arrangement of pores in the ZnO samples prepared using dextrose and urea as fuels. The photodegradation ability of the various synthesized photocatalysts was tested for the photodegradation of an azo dye, namely, orange G dye solution. ZnO photocatalyst prepared using oxalic acid as fuel showed the highest decolorization and degradation ability under UV light irradiation