Synthesis, characterization and photocatalytic activities of Al-doped ZnO for degradation of methyl orange dye under UV light irradiation

Semiconductor photocatalysts with better photocatalytic properties have been widely researched to be an alternative for dye removal application with better photocatalytic properties. In the present work, Al-doped ZnO which act as a photocatalysts was prepared by modified sol-gel technique at different Al concentrations to evaluate the effect of different Al doping concentration towards the photocatalytic degradation performance of methyl orange dye. The crystallinity of Al-doped ZnO was analysed by X-ray diffraction (XRD) at room temperature. The structural properties, surface morphology and elemental composition were studied via scanning electron microscope (SEM) attached with energy dispersive X-ray spectroscopy (EDS). From XRD, all Al-doped ZnO samples show a polycrystalline nature with a hexagonal wurtzite structure. The average crystallite size was determined by Scherrer’s equation in the range of 79.29–86.50 nm. The Al ion was successfully incorporated into the Zn lattice confirmed by (101) peak shifting from the XRD results. The photocatalytic activities have been carried out by irradiating the photocatalysts under ultraviolet (UV) irradiation. The 1 mol% Al-doped ZnO exhibited a significant increase in the percentage degradation and photocatalytic efficiency compared to others with value of 88.87% degradation and rate constant k of 3.45 × 10−2 min−1 under 60 min irradiation. In the present work,  Al-doped ZnO could be reused minimum of five cycles in its recyclability reaction.