Synthesis of yttrium oxide nanoparticles via a facile microplasma-assisted process

Plasma electrochemistry is an emerging technique for nanomaterial synthesis. The present study reports the preparation of yttrium oxide nanoparticles via a simple, environmentally benign, microplasma-assisted process operated in pin-to-liquid configuration under ambient atmospheric conditions using yttrium nitrate aqueous solution as the precursor. The plasma-liquid interaction was monitored in-situ by optical emission spectroscopy. The morphology, structure and chemical composition of the obtained products were examined by complementary analytical methods. It was demonstrated that high purity crystalline Y₂O₃ nanoparticles with adjustable sizes can be fabricated via a two-step method: plasma electrodeposition of yttrium hydroxide followed by heat-treatment at various temperatures. A microplasma array design was proposed for the process upscaling towards industrial level production. Moreover, possible mechanisms for plasma-assisted yttrium hydroxide precipitation were discussed by correlating optical emission spectroscopic studies, plasma kinetic analysis and the precipitation equilibrium. As a proof-of-concept, this process offers a facile, environmental friendly and scalable route for rare-earth oxide nanomaterial synthesis.