Synthesis of Ni/Y2O3 Nanocomposite through USP and Lyophilisation for Possible Use as Coating

The Ni/Y₂O₃ catalyst showed high catalytic activity. Based on this, the aim of this study was to create Ni/Y₂O₃ nanocomposites powder with two innovative technologies, Ultrasonic Spray Pyrolysis (USP) and lyophilisation. In the USP process, thermal decomposition of the generated aerosols in an N₂/H₂ reduction atmosphere caused a complete decomposition of the nickel (II) nitrate to elemental Ni, which became trapped on the formed Y₂O₃ nanoparticles. The Ni/Y₂O₃ nanocomposite particles were captured via gas washing in an aqueous solution of polyvinylpyrrolidone (PVP) in collection bottles. PVP was chosen for its ability to stabilise nano-suspensions and as an effective cryoprotectant. Consequently, there was no loss or agglomeration of Ni/Y₂O₃ nanocomposite material during the lyophilisation process. The Ni/Y₂O₃ nanocomposite powder was analysed using ICP-MS, SEM-EDX, and XPS, which showed the impact of different precursor concentrations on the final Ni/Y₂O₃ nanocomposite particle composition. In a final step, highly concentrated Ni/Y₂O₃ nanocomposite ink (Ni/Y₂O₃ > 0.140 g/mL) and test coatings from this ink were prepared by applying them on a white matte photo paper sheet. The reflection curve of the prepared Ni/Y₂O₃ nanocomposite coating showed a local maximum at 440 nm with a value of 39% reflection. Given that Ni is located on the surface of the Ni/Y₂O₃ nanocomposite in the elemental state and according to the identified properties, tests of the catalytic properties of this coating will be performed in the future.