Influence of yttrium doping on ZnO nanoparticles for enhanced photocatalytic degradation of methylene blue

In this work, Y-doped ZnO nanoparticles were precipitately synthesized for various yttrium molar percentage values ranging from 0 to 5%, and then utilized as photocatalysts to demonstrate methylene blue degradation. Morphology shows that the particle size of pure ZnO is 113.77 +/- 33.26 nm, which is reduced to the minimum value less than one-third for the Y-doped ZnO samples. As a result, surface-to-volume ratios of Y-doped ZnO samples have successfully increased due to their decreased size. This decrease in particle size is consistent with the small crystalline size, primarily due to low crystallization in the presence of yttrium doping. However, the expansion of the crystal structure is observed. Chemical surface structures point to the major vibration of ZnO. However, some carbon-relating groups remain to appear. Optical property reveals similar trends for all Y-doped ZnO samples. The estimated band gap energy (E-g) was reduced to the minimum value for the 4 mol% condition. For use as a photocatalyst, the appropriate Y-doped ZnO for 4 mol% yttrium doping presents the maximum degradation efficiency of 61.19%. The improvement in photocatalytic degradation is caused by the synergy of decreased particle size and reduced E-g. Therefore, yttrium plays a role to decrease particle size and reduce E-g of Y-doped ZnO materials, thus leading to enhance photocatalytic performance.