Methylene blue degradation using ZnO:CuO:Al2O3 nanocomposite synthesized by liquid laser ablation

Colored dyes are major sources of environmental pollution. Mineralization using heterogeneous catalysts is the method to remove such environmental pollutants. Herein, a green approach is used to prepare the nanocomposites, in which pulsed laser ablation of liquid (PLAL) is used. The synthesis of a ternary nanocomposite of ZnO/CuO/Al2O3 as a photocatalyst to degrade methylene blue (MB) dye is performed in an optimized ratio of 3:1:1 at pH = 10.37. To evaluate the structural, morphological, and optical features of the synthesized ternary nanocomposite, XRD, Raman spectroscopy, scanning electron microscopy (SEM), EDS, atomic force microscope (AFM), and UV-vis spectroscopy are used. The XRD pattern confirms that the ternary nanocomposite is highly crystalline in nature. The Raman spectra confirm the formation of the ternary ZnO/CuO/Al2O3 heterostructures. The AFM images of the ratio 3:1:1 show less agglomeration than the 1:3:1 and 1:1:3 ratios. The SEM images show agglomerated spheroids with rice-like morphologies and a mean particle size of around 40 nm. The energy bandgap (E-g) values lie in the UV region at 5.05, which means that the photocatalyst has enhanced its photocatalytic activity under sunlight. The degradation efficiency of 3:1:1 at pH = 10.37 achieves the highest value of 98.55% with a rate constant of 0.2265 min(-1) after 15 min of illumination.