Enhanced Photocatalytic Activity and Charge Carrier Separation of a Nickel Impregnated Zinc Oxide Catalyst for the Visible Photodegradation of Remazol Brilliant Violet-5R and Methyl Orange

Abstract

ZnO was impregnated with Ni in order to increase its photocatalytic performance in the visible region. The Ni-impregnated ZnO catalyst was synthesized by wet impregnation. The synthesis of Ni/ZnO catalyst, its morphological analysis and elemental analysis was confirmed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) spectroscopy which confirmed that 4.66% Ni was impregnated at the surface of ZnO. The synthesized catalyst was applied for the photocatalytic degradation of Remazol Brilliant Violet-5R (RBV-5R) and methyl orange (MO) in aqueous solution. The catalyst dosage, pH, dye concentration, and effect of scavengers were optimized. 98.92% degradation of RBV-5R was observed at pH 10 using 0.1 g of catalyst, 5 mmol H₂O₂ in 20 min, whereas 83.77% MO was degraded using 0.2 g of the catalyst at pH 4 in 30 min. The order of reaction was also determined by applying kinetic models and the degradation followed pseudo first-order kinetics for both dyes.

Keywords:

• Methyl orange
• photocatalytic degradation
• Remazol Brilliant Violet-5R
• spectrophotometry