Substitution of Al3+ to Zn2+ sites of ZnO enhanced the photocatalytic degradation of methylene blue under irradiation of visible light

Abstract

Al-doped ZnO nanoparticles (n-AZO) were synthesized by sol-gel method and tested their photocatalytic degradation of MB under visible light irradiation. The micro-structural and optical properties of n-AZO were evaluated from XRD, FE-SEM, HR-TEM, SAED, FTIR and UV-Vis techniques. The presence of Al in ZnO lattice was confirmed from EDAX-mapping, and XPS-elemental analysis. XRD-peak profile analysis and SAED pattern of n-AZO confirmed the substitution of Al3+(0.53 angstrom) on to Zn2+(0.73 angstrom) sites without changing the hexagonal structure of ZnO. The particular dopant concentration of Al-ions (Al = 5 at%) revealed the superior visible light photocatalytic degradation of MB due to decreasing the particle size and increasing the catalytic functional sites. The highest photocatalytic degradation of MB was achieved to be similar to 94% within 60 min and showed the remarkable degradation of the organic pollutant under the illumination of visible light.