High Speed Shearing: A novel approach for high-quality ZnO nanoparticle synthesis and photocatalytic activity control

Zinc oxide (ZnO) nanoparticles show the great promise in photocatalysis due to their exceptional characteristics. However, achieving precise control over ZnO nanoparticle size, morphology, and agglomeration remains a challenge. We applied the high-speed shearing (HSS) method for synthesizing ZnO with enhanced properties. HSS employs a high-speed rotor to generate intense shear forces, enabling efficient particle size reduction, improved homogeneity, and enlarged surface area. HSS method could provide crushing effect and powerful mixing effect to synthesize smaller ZnO nanoparticles with less agglomeration. ZnO nanoparticles are optimized from 9.69 nm to 7.09 nm for single particle and from 955 nm to 26.5 nm for secondary particle size. Ultraviolet diffuse reflectance spectroscopy has been used to further analyze the in-situ formation reaction. Besides, we investigate the photocatalytic efficiency of ZnO towards methylene blue. ZnO nanoparticles made using HSS have more active sites, improving the photocatalytic degradation from 38.6% to 70.8%.