Synthesis of CeO2 nanocrystalline powders using DC non-transferred thermal plasma at atmospheric pressure

•Nanocrystalline CeO2 powders were synthesized by DC thermal plasma.•Properties of CeO2 nanocrystalline powders were investigated.•Photocatalytic activity of CeO2 nanocrystalline powders was evaluated.

Nanocrystalline CeO2 powders were synthesized by using a DC non-transferred thermal plasma system at atmospheric pressure. Ce(NO3)3·6H2O powders were employed as a raw material and a cerium nitrate solution was used as a precursor. The liquid precursor was injected into a cylindrical reactor through two different directions: the vertical and the horizontal direction. The difference of the properties of CeO2 nanocrystalline powders according to the directions of injection were investigated by using XRD, TEM and an UV/VIS/NIR spectrometer. For the horizontal case, the cylindrical reactor acted as a cyclone providing greater tangential velocities. The higher tangential velocities increased the centrifugal forces of as-synthesized powders causing the thicker deposition layer of powders at the upper part of the reactor. The thicker deposition layer of powders was considered as the reason of the less heat treatment of powders prepared. This was confirmed by the relatively lower intensities of XRD peaks. In addition, CeO2 nanocrystalline powders were tested as a photocatalyst using the gaseous 2-propanol decomposition. For the test, the photocatalytic activity was defined and evaluated. It appears that CeO2 nanocrystalline powders are more suitable for the treatment of the dyes in the wastewater than the removal of the volatile organic compound (2-propanol).

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