Page 123 - 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
(a) (b)
Y3d
Y3d3/2(158.4 eV)
Y3d3/2(160.1 eV) Y3d5/2 (158 eV)
Y3d5/2(156.4 eV)
1200 1000 800 600 400 200 0 164 162 160 158 156 154 152 Binding energy (eV) Binding energy (eV)
(c)
O1s
531.3 eV
532.5 eV
529 eV
536 534 532 530 528 526 Binding energy (eV)
Figure 6.9 (a) Full XPS spectrum of Y2O3 NPs annealed at 600 °C; (b) XPS spectrum of Y3d; (c) XPS spectrum of O1s
As described above, we have demonstrated a proof-of-concept synthesis of high purity crystalline Y2O3 nanoparticles with adjustable sizes via a two-step method: plasma electrodeposition of yttrium hydroxides followed by calcination at various temperatures. In this manner the usage of other chemicals are not needed, which helps to significantly reduce potential side reactions and impurities as well as obviate complex post treatments to improve the product purity. On the other hand, it is worth highlighting that the throughput of the current process is relatively low, since in this lab-scale study only a single microplasma jet is applied for the electrodeposition of yttrium hydroxides. As a consequence, the plasma-liquid interactions are confined within a relatively small spatial zone. However, this limitation can be overcome by the design of a microplasma array, in which plasma jets are arrayed in two dimensions to increase the surface area for plasma-liquid interaction.31 For example, if we use the same size SS capillary (I.D.= 318 μm, O.D.= 1.6 mm) in a 100×100 square array, the plasma-liquid interaction surface would be increased by four orders of magnitude. Meanwhile, due to the extremely small dimension of the single microplasma jet, such an
111
Intensity (a.u.)
C1s Y4s Y4p
Y3s
Y3p
Intensity (a.u.) CKLL
OKLL
Y3d Intensity (a.u.)
O1s