Developing binary spinel type metal oxide based films via Solution Precursor Plasma Spray Process for its functional applications

Binary spinel type (AB₂O₄) metal oxides semiconductors (MOS) have been attractive for photocatalytic applications due to their excellent visible light response and good photochemical stability. And developing a novel efficient one-step process to synthesize porous binary spinel type MOS films for photocatalytic degradation of organic pollutant is necessary for industrial promotion. Herein, different spinel type MOS based photocatalytic films, including ZnCo2O4, ZnFe2O4 and CoFe2O4, were successfully obtained via such an industrial-friendly single-step Solution Precursor Plasma Spray process. In this investigation, different mole ratios between two different metal ions (such as Zn/Co, Zn/Fe and Co/Fe) were employed to study the corresponding effect on phase composition of resultant films. Besides, surface morphologies, composition phase and bandgap of ZnCo2O4, ZnFe2O4 and CoFe2O4 films deposited via SPPS were also investigated by using different solution flow rates, solution concentrations and substrate preheating temperature. In addition, photocatalytic activities of some promising binary spinel type films were evaluated by degradation of Orang II dye aqueous under different light irradiations. Furthermore, this work reveals that SPPS process provides a promising alternative to orthodox multi-step processes for preparing complex composition photocatalyst.

Keywords: Solution precursor plasma spray, Binary spinel phase, Microstructure, Bandgap, Photocatalytic degradation