Kourosh motevalli - Department of Applied Chemistry, Islamic Azad University, South Tehran Branch, Tehran, Iran
Zahra yaghoubi - Faculty of Industrial Engineering, Islamic Azad University, South Tehran Branch, Tehran, Iran

In this paper, we try to verify the main aspects of ZrO2, zirconium dioxide, as a helpful photocatalyst. This matter has some usages such asdecomposition and diminution of environmental water and air pollutants. In such applications, it can be used as slurry or as immobilized coating obtained by different deposition methods. The studies performed in the last years showed that thermal spraying could be employed to elaborate ZrO2 coatings with high performance for the decomposition of organic compounds. This manuscript presents a comparative study on the microstructure and photocatalytic performance of Zirconia coatings obtained by different thermal spray techniques: atmospheric plasma spraying (APS), suspension plasma spraying (SPS), and high-velocity oxygen fuel spray process (HVOF). Different zirconia powders and suspensions were used to study the influence of the feedstock materials on the coating characteristics. The deposits were mainly characterised by SEM and X-ray diffraction. The photocatalytic performance was evaluated from the removal of nitrogen oxides. Eventually , The final results showed that a drastic reduction of the pollutant concentration was obtained in presence of coatings elaborated by suspension plasma spraying. ZrO2 coatings resulting from the spraying of agglomerated powder presented less efficiency. As a photocatalyst, Zirconium dioxide can be used in the degradation of air and water pollutants, and in medical sterilization.

photocatalyst, SEM, coatings, environmental,aggregates, nanopowders