ZnS Nano-Spheres Formed by the Aggregation of Small Crys- tallites and Their Photocatalytic Degradation of Eosin B

• Published in: 中国化学：英文版 2017, Vol.35 (2), p.159-164
• Main Author: Sovann Khan Joon Soo Han SeungYong Lee So-Hye Cho
• Format: Article
• Language: English
• ISSN: 1001-604X; 1614-7065

Monodispersed ZnS nano-spheres were synthesized by a simple precipitation. By adjusting the concentration of Zn and S sources, the particle size and morphology were easily controlled. Careful examination of the obtained par- ticles suggested porous structures composed of building blocks of small crystallites, ca. 4-- 13.4 nm in diameter. A higher [S]/[Zn]-precursor ratio resulted in a bigger crystallite size but a smaller particle size, and vice versa, for the lower precursor ratio. However, an extreme [S]/[Zn] ratio of 20 provided no spherical aggregation, but a formation of amorphous aggregates. We consider the rate to nucleation and the diffusion-controlled aggregation of crystallites to be important parameters in determining particle sizes and size distributions. Size homogeneity of the obtained ZnS nano-spheres, especially with a [S]/[Zn]-precursor ratio of 5, afforded a photonic crystal array that can poten- tially benefit the photocatalytic activity. When the photocatalytic activities of the ZnS nano-spheres obtained via different conditions were compared, it was found that spherical aggregation and high surface areas have a positive effect on catalytic activity. Although using a [S]/[Zn] ratio of 20 provided the highest surface area, the amorphous aggregation and overly excessive use of S caused a detrimental influence on the catalytic activity.