Page 115 - Synthesis of Functional Nanoparticles Using an Atmospheric Pressure Microplasma Process - LiangLiang Lin

Yttrium Oxide Nanoparticles Synthesis - a Model Study on the Plasma-Liquid Interaction and Opener to Nanophosphors
in plasma, without the use of any other chemicals like oxalic acid, alkali, surfactants and stabilizers. Meanwhile, this method obviates the use of coupled procedures like filtration or centrifugation to improve product purity, which greatly simplifies the overall synthesis workflow.
6.2 Experiment Section
6.2.1 Experimental
To synthesize nanoparticles in the liquid phase, the microplasma reactor was modified, as schematically shown in Figure 6.1. Detailed information can be referred to the Figure 2.3. For all experiments, 8 ml Y(NO3)3·6H2O (Sigma-Aldrich) solution (0.05 mol/L) was placed in the reactor as the electrolyte. A 50 sccm argon flow was coupled to the capillary tube during experiment, with flow rate controlled by a mass flow controller unit. During the experiment the output voltage was fixed at 5000 V, and the process time was set to 3 hours. Meanwhile, the reactor design allowed in-situ monitoring of the operating plasma by optical emission spectroscopy, and visual observation of the spatially distributed hydroxide deposits. After plasma treatment, the hydroxide deposits of electrolyte were washed and dried at 80 ˚C for 12 h to obtain hydroxide powders. For the oxide products derivation, the as-obtained hydroxide powders were heat-treated for 3 hours at various temperatures (600-1200 ˚C) with the temperature rise to preset value at a heating rate of 10 ˚C /min. The annealed products were scraped from the crucible for further characterization.
Figure 6.1 The schematic micro reactor for the synthesis of yttrium hydroxide
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