Nanocrystalline immobilised ZnO photocatalyst for degradation of benzoic acid and methyl blue dye

Abstract ZnO thin films were deposited with different solution quantities using spray pyrolysis technique. The effect of thickness variations on photoelectrochemical (PEC), structural, morphological and optical properties are studied. PEC measurements showed maximum photo response about Isc = 0.485 mA and Voc = 632 mV at 1.65 μm film thickness. X-ray diffraction study confirms that the films are polycrystalline with hexagonal crystal structure. Hexagonal shaped grains are observed conformed from surface morphology. The estimated bandgap energy of ZnO films are varies between 3.23 to 3.29 eV. Finally large area (10 × 10 cm2) deposited ZnO photoelectrode were used to study the photocatalytic and photoelectrocatalytic degradation of benzoic acid (BA) and methyl blue (MB) dye under UV radiation. Photoelectrocatalytic degradation result shows 65.7% degradation of BA and for colorant organic compound such as MB dye is about 98.1% is possible. The mineralization of pollutants are studied by measuring chemical oxygen demand (COD) values.