TiO2/SiO2 Coated 310S Stainless Steel for Hydrogen Peroxide Generation Via Photocatalytic Reaction

The photocatalytic reactor was designed by assembling the parts of a photocatalyst, an ultraviolet light source and an air distribution. This prototype reactor was used to generate H₂O₂ via photocatalytic reaction. TiO₂ and TiO₂/SiO₂ prepared from sol-gel method were coated on 310S stainless steel substrate using dip-coating technique. Rice husk ash was used as the source of SiO₂. The major phase of all the pure TiO₂ and SiO₂ particles was anatase and amorphous, respectively. The surface analysis showed the coated TiO₂ and TiO₂/SiO₂ with an average roughness of 365.391 and 1322.001 nm, respectively, compared with the average thickness of coated TiO₂ which was measured to be 2.7325 μm and for TiO₂/SiO₂, which was 4.7856 mm. The results also showed the coating of TiO₂/SiO₂ was highly porous at the surface compared with pure TiO₂. The TiO₂/SiO₂ show good photocatalytic reaction activity because SiO₂ doping on TiO₂ increased the adsorption of O₂ and H₂O molecules towards the photoactive center of TiO₂. Thus, the incorporation of SiO₂ onto the photocatalyst helped to increase photocatalytic activity. The generation of H₂O₂ increased with increasing ambient humidity up to 60% RH, but then decreased. This behavior was explained by the effect of water vapor adsorption on the SiO₂ surface. The air flowrate enhanced the generation of H₂O₂, higher air flow rate produced a higher amount of H₂O₂. H₂O₂ was generated at the highest concentration of 64 ppmv from the TiO₂/SiO₂ photocatalyst at ambient humidity of 60% RH and air flowrate 8.20 m/s.

Keywords: TiO₂/SiO₂; photocatalysis; hydrogen peroxide

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