Effect of Metal Doping on the Band Gap Energy of Zirconia: Photocatalytic Degradation of Acid Red 4

Abstract ZrO 2 , Sn@ZrO 2 , Pd@ZrO 2 , and Ni/Pd@ZrO 2 were synthesized as an efficient photocatalyst using an induced microwave irradiated coprecipitation procedure. The synthesized catalysts were screened for photodegradation of azo model dye (Acid Red 4: AR‐4) under UV irradiation. Ni/Pd@ZrO 2 showed excellent catalytic efficiency. The crystallinity of materials was confirmed by X‐ray diffraction (XRD) pattern, while surface morphology was investigated by Scanning Electron Microscopy (SEM). The composition of synthesized catalysts was studied by elemental mapping and EDX. HRTEM analysis showed small a change in the d‐spacing of Pd@ZrO 2 , Ni/Pd@ZrO 2 , which was attributed to crystal defects and their enhanced photocatalytic efficiency. Different reaction parameters (dye concentration, catalyst dose, pH, and temperature) were optimized for achieving the best photocatalysis. The kinetic study showed the degradation of AR‐4 proceeds through a pseudo‐first order kinetic model. The catalyst was separated from the reaction medium, washed, dried, and reused for five experimental runs in order to demonstrate the stability and reusability of the catalyst.