A combined technique of photo-doping and MOCVD for the development of heterogeneous photo-Fenton catalyst

A novel technique combining photo-doping and metal-organic chemical vapor deposition (MOCVD) is used to synthesize heterogeneous iron (Fe) catalyst supported on TiO2/SiO2 substrate. The TiO2/SiO2 substrate is obtained through MOCVD method to disperse TiO2 onto silica gel and then iron is coated onto the substrate by photo-doping. The developed catalyst, Fe/TiO2/SiO2, is characterized by various techniques, including ICP-OES, XRD, XPS, and physisorption. It is found that the doped ferric ion is selectively deposited on the TiO2 layer of the catalyst surface without any significant change of the BET specific surface area. XPS spectrum further proves that the doped iron is in trivalent form and mainly distributed on the catalyst surface. The developed catalysts are evaluated in the photo-Fenton degradation on a dye pollutant, Orange II. Complete discoloration and 80% of mineralization can be achieved. A calcination step is required after the photo-doping in order to minimize the iron leaching during the photo-Fenton reaction.