Preparation of zinc peroxide nanoparticles by laser ablation of solid in liquids

We report the preparation of zinc peroxide nanoparticles (ZnO2 NPs ) by the laser ablation of solid in liquids technique. Experiments were performed by using the fundamental wavelength (1064 nm) of a pulsed nanosecond Nd:YAG laser operated at a repetition rate of 15 Hz. A Zn disk (99.99 % purity) were the target and 10 ml of 30% H2O2 solution was used as liquid medium. The per pulse laser fluence was varied. In all the experiments the ablation time was 10 min. The samples were characterized by Raman microspectroscopy, Calorimetry and TEM. Results show that ZnO2 NPs were successfully obtained by this method of preparation

Study of the Performance of the Organic Extracts of Chenopodium ambrosioides

There are many ways to obtain metal nanoparticles: biological, physical, and chemical ways and combinations of these approaches. Synthesis assisted with plant extracts has been widely documented. However, one issue that is under discussion refers to the metabolites responsible for reduction and stabilization that confine nanoparticle growth and prevent coalescence between nanoparticles in order to avoid agglomeration/precipitation. In this study, Ag nanoparticles were synthesized using organic extracts of Chenopodium ambrosioides with different polarities (hexane, dichloromethane, and methanol). Each extract was phytochemically characterized to identify the nature of the metabolites responsible for nanoparticle formation. With methanol extract, the compounds responsible for reducing and stabilizing silver nanoparticle were associated with the presence of phenolic compounds (flavonoids and tannins), while, with dichloromethane and hexane extracts, the responsible compounds were mainly terpenoids. Large part of the reducing activity of secondary metabolites in C. ambrosioides is closely related to compounds with antioxidant capacity, such as phenolic compounds (flavone glycoside and isorhamnetin), which are the main constituents of the methanol extracts. Otherwise, terpenoids (trans-diol, α-terpineol, monoterpene hydroperoxides, and apiole) are the central metabolites present in dichloromethane and hexane extracts