Mesoporous Technische Universiteit Delft (TUD-1)-supported chromium oxide-doped titania (Cr-TiO2) was developed as a promising photocatalyst for phenol photodegradation under visible light irradiation. Low-angle X-ray diffraction and Fourier transform infrared spectroscopy results confirmed the amorphous and mesoporous silicate framework of TUD-1 in TUD-1-supported Cr-TiO2. The mesostructure of TUD-1 was further verified via N2 adsorption-desorption analysis, which showed a type-IV isotherm with a narrow average pore size distribution of 3.9 nm and high surface area of > 490 m 2 /g. Transmission electron microscopy analysis results indicated that TUD-1-supported Cr-TiO2 contained nanoparticles and porous channels. An increase in band gap energy was observed after loading Cr-TiO2 into TUD-1. Compared with that of unsupported Cr-TiO2, TUD-1-supported Cr-TiO2 showed higher photocatalytic activity for phenol degradation under visible light irradiation. The TUD-1 supported Cr-TiO2 photocatalyst with a Si/Ti molar ratio of 30 exhibited the highest photodegradation of phenol (82%) of the prepared samples. The photodegradation of phenol by the supported catalyst followed the Langmuir adsorption isotherm with first-order kinetics.

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An attempt has been carried out to prepare vanadia loaded TiO2 supported on MCM-41(V-TiO2/MCM-41) nanostructured photocatalysts using different surfactants. The surfactants used in the photocatalysts synthesis were dodecyl-trimethyl-ammonium bromide (DTAB), hexadecyl-trimethyl-ammonium bromide (CTAB) and octadecyl-trimethyl-ammonium bromide (STAB) which have varied carbon chains. The effect of crystallinity, surface area and porosity of the MCM-41 support on the physical-chemical properties of synthesized photocatalysts of vanadia loaded TiO2/MCM-41 and their photocatalytic performance were investigated. X-ray diffraction (XRD) patterns showed that the crystallinity of vanadia-TiO2/MCM-41 decreased with increasing of carbon-chain number of the surfactant used. Both surface area and pore volume of V-TiO2 increased significantly from 16.2 m2/g and 0.034 cm3/g to 864.3 m2/g and 0.618 cm3/g, respectively, after being loaded on MCM-41 support which was prepared using CTAB. It was demonstrated that all the V loaded TiO2/MCM-41 materials exhibited remarkable improvement in photocatalytic degradation of methylene blue (MB) under the irradiation of visible light as compared to that of bare TiO2 and V-TiO2. Among these materials, V-TiO2/MCM-41 which was synthesized using CTAB appeared to be the best photocatalyst with 57% of MB removal under visible light irradiation.

Nanocrystalline spinel ferrites with general formula of MnxZn1−xFe2O4; x = 1.0, 0.8, 0.6, 0.4, 0.2, 0.1 were prepared via co-precipitation method at 75 °C and pH 11. The XRD results showed that the doping of Zn ions into ferrite’s structure resulted in the reduction of both crystallinity and crystallite size.  The results also revealed that the synthesized MnxZn1−xFe2O4 crystalline in spinel cubic structure with particle size range of 13.0 – 22.5 nm. Field emission scanning electron microscopy (FESEM) images showed an increase in particle size with the decreasing Zn content. The types of chemical covalent bonds which existed in the samples were determined via Fourier transforms infrared (FTIR) spectroscopy.

A series of visible light driven photocatalysts of Cr-doped TiO2 and Cr-doped TiO2 supported on TUD-1 have been successfully synthesized via surfactant-free sol-gel method followed by wet impregnation procedure. XRD analysis revealed that both anatase and rutile phases existed in Cr-doped TiO2 samples. After loading onto TUD-1, both Ti and Cr were incorporated in the highly porous siliceous matrix. As observed, more tetrahedrally coordinated Ti species was formed in Cr-doped TiO2 after supporting onto TUD-1. The photocatalytic performance of the synthesized materials was tested in the photodegradation of Methylene Blue under visible light irradiation. Results showed that 2.5 mol% Cr dopant gave the highest photocatytic activity to TiO2 in dye photodegradation. Besides, all the 2.5Cr-TiO2 supported on TUD-1 materials had higher photocatalytic activity than that of 2.5Cr-TiO2. Among the materials prepared, 2.5Cr-TiO2/30TUD-1 appeared as the most superior photocatalyst which gave the highest dye photodegradation of 75%.