Synthesis of raspberry-like structure zinc oxide nanoparticles via glycol-solvothermal, low-temperature solvothermal and coprecipitation methods

Highly crystalline ZnO nanoparticles with a pure phase and raspberry-like structure were synthesized using three different techniques (glycol-solvothermal, low-temperature solvothermal, and coprecipitation methods). Physisorption analysis and field emission scanning electron microscopy confirmed the large specific surface area of the ZnO nanoparticles with a mesoporous–macroporous structure due to the interstices of aggregated and agglomerated secondary and tertiary ZnO particles. The ZnO nanoparticles from the coprecipitation method presented the best performance among the three products, owing to their highest purity and crystalline phase, large Brunauer–Emmett–Teller surface area (23.0 m2${\cdot }$g$^{-1}$) and pore volume, and the finest mesoporous–macroporous structure. ZnO nanoparticles can be used in various applications such as catalysis, biosensing, imaging, drug delivery, and pollution absorption for the purpose of environmental remediation.