Aluminium Doped Zinc Oxide Tripod Nanostructures Synthesised Via Hot Tube Thermal Evaporation For Photo-Decolourisation Of Methylene Blue

Water pollution is one of the most concern in modern society today. The increase in the need of clean water and to sustain environmentally friendly have motivated the advancement in development of water cleaning technology. Therefore, photocatalysis is introduced as an alternative treatment to purify wastewater. This research aims to synthesis aluminium doped zinc oxide (Al-doped ZnO) as photocatalyst using low cost hot-tube thermal evaporation method. Six samples were prepared by varying the wt% of Al dopant (S1=1wt%, S2=2wt%, S3=3wt%, S4=4wt%, S5=5wt% and S6=6wt%) during the deposition process. FESEM shows all samples showing different types of morphology with S3 (3wt%) closely grown a wurtzite hexagonal rod shaped. EDX spectra shows all samples exhibit sharp peaks of Zn followed by O2 and Al proves that all samples were well produced. Furthermore, the strongest diffraction peak for XRD of all samples was found at (101), exhibiting a single crystalline hexagonal structure with c-axis direction. Band gap values were calculated using Kubelka-Munk function and S3 (3wt%) has the lowest value of band gap with 2.8 eV. As a result of structural and optical characterisation, S3 (3wt%) was selected as the optimum sample to undergo the photo-decolourisation of methylene blue solution. Significant result proves that ZnO doped with 3wt% of Al dopant succeed to decolourise the methylene blue solution with efficiency is 22.86% over the time.