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 m. 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.