Mesoporous ZnO nanoclusters as an ultra-active photocatalyst

Morphology modulation of nanostructured materials are highly crucial for various applications including photocatalysis, drug delivery, etc. In this study, mesoporous zinc oxide (ZnO) nanoclusters (MZN) were synthesized via a simple, cost-effective, low-temperature wet chemical route and further sucessfully utilized for photodegradation of Rhodamine B (RhB). Firstly, polystyrene (PS) nanospheres (~300 nm) were prepared by polymerization of styrene in aqueous solvent. Then the MZN were achieved by formation of ZnO nanoparticles-shell over the surface of PS nanospheres via esterification of zinc acetate dihydrate in isopropyl alcohol followed by toluene dissolution of PS core. The as-synthesized MZN were spherically-shaped, porous in nature with a diameter of ~ 400 nm and composed of well-arranged highly-crystalline ZnO nanoparticles (~ 5 nm). The MZN also exhibited a high surface area of 78.3±5.4 m2 g−1 and an average pore diameter of ~26 nm. Furthermore, this unique structure demonstrates an expeditious photodegradation of RhB under UV illumination, monitored by UV–visible spectroscopy at different time intervals until the dye was completely degraded to colorless end products. Fast RhB decomposition was observed with a degradation rate of ~98% within initial 40 min which can be attributed to the porous nature, large specific surface area and excellent electron accepting features of the engineered nanoclusters.