Mesostructured technische universiteit delft-1 and technische universiteit delft-crystalline supported metal oxide doped titania as photocatalyst and oxidative catalyst

This research focused on the development of new Technische Universiteit Delft (TUD)-supported catalysts that are applicable for the photodegradation of organic pollutants and for the epoxidation of various olefins. In this study, the feasibility of relatively new mesoporous materials namely Technische Universiteit Delft-1 (TUD-1), amorphous silica material and Technische Universiteit Delft- Crystalline (TUD-C), hierarchical zeolitic material with MFI framework as the support for transition metal oxide doped titania was investigated. Two series of samples TUD-1 supported Cr doped TiO2 (Cr-TiO2/TUD-1(x)) and TUD-C supported Mo doped TiO2 (Mo-TiO2/TUD-C(y)) were synthesized via a single softtemplating approach involving the combination of sol-gel and hydrothermal treatment. The synthesized materials were characterized using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Diffused Reflectance Ultraviolet-visible Spectroscopy (DRUV-Vis), Nitrogen adsorption-desorption surface analysis, Temperature Programmed Desorption of Ammonia analysis (NH3- TPD), X-ray Photoelectron Spectroscopy (XPS), Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM). Optimization was carried out by varying the Si/Ti molar ratio in TUD-1 (x = 10 – 50) and Si/Al molar ratio in TUD-C (y = 10 – 50). For the photocatalytic reactions, results demonstrated that all the TUD-1 supported Cr-TiO2 materials were better photocatalysts compared to that of unsupported Cr-TiO2. Cr-TiO2/TUD-1(30) achieved the highest photodegradation percentage for Malachite Green (75.6%), Congo Red (50.8%) and phenol (82.0%) under visible light irradiation. The adsorption of phenol followed the Langmuir adsorption isotherm, while the photodegradation of phenol obeyed the first order kinetics. As for the oxidative reactions, Mo-TiO2 supported on TUD-C, with Si/Al molar ratio = 10 exhibited the highest epoxide yield for various types of olefins at ambient conditions. As compared to the unsupported Mo-TiO2, TUD-C supported Mo-TiO2 samples showed significantly higher conversion with 100% selectivity towards formation of epoxides. All the epoxidation reactions followed the first order kinetics. The increment of catalytic activities for both series of materials is attributed to the high surface area (496 – 1034 m2/g) and tunable porosity (2.83 – 5.84 nm), which provides better adsorption and diffusivity. The excellent oxidative capabilities of TUD-C supported materials were also accounted for the increased acidity originated from the aluminosilicate framework. Effect of reaction parameters including initial concentration (100 - 500 ppm), pH (2 - 11), catalyst amount (0.05 - 0.5 g), and reaction duration (6 - 72 h) in both photocatalytic and oxidative reactions were studied. TUD-1 and TUD-C are promising catalyst supports and have significantly improved the photocatalytic and catalytic performance of the transition metal oxides doped TiO2

Cr doped TiO2 supported on TUD-1 photocatalyst for congo red photodegradation

A series of new visible light driven photocatalysts of 1 mol% Cr doped Ti02 supported on various amount of TUD-1 have been successfully synthesized via sol gel method. XRD analysis revealed that all the Cr-Ti02/x TUD-l (x = 10,20,30,40 and 50 mol%) photocatalysts were in amorphous form. Both Ti02 and Cr were incorporated in the highly porous siliceous matrix. FTIR analysis indicated the existence of Si-O-Ti bonding in all the materials. UV-Vis D R analysis suggested that alteration of Ti species occurred from tetrahedrally to octahedrally coordinated Ti species when higher TUD-1 amount was used as photocatalyst support. However, the amount of TUD-1 did not affect the wavelength response and the band gap energy of the resulted materials. All the materials were having band gap energy of ~2.9 eV. The photocatalytic performance of the synthesized materials was evaluated through the photodegradation of Congo Red under visible light irradiation at 298 K for 5 h. Results showed that all the Cr-TiO2/TU D -1 materials had higher photocatalytic activity compared to Cr-TiO2, Amongst, Cr-TiO2/30TU D-1 appeared as the most superior photocatalyst that gave the highest percentage of dye degradation

Synthesis and characterization of molybdena and phosphate doped silica-titania oxidative catalyst for epoxidation of styrene

New oxidative catalysts of molybdena and phosphate doped silica-titania (xMo/PO4 3-/ SiO2-TiO2, x = 0, 1, 2, 4 and 5 wt%) have been prepared in this study. Silica-titania was prepared via sol-gel method by using titanium isopropoxide and tetraethyl orthosilicate as precursors of titania and silica, respectively. Sufficient amount of ammonium molybdate tetrahydrate and 0.2 M phosphoric acid were loaded on silica-titania through impregnation method. The XRD results confirmed the amorphous phase of all the samples Mo/PO4 3-/ SiO2-TiO2, indicating well dispersion of Mo, phosphate and Ti on the silica support. DRUV-Vis analysis revealed the existence of both tetrahedral and octahedral Ti species in the samples. The N2 adsorption surface area analysis showed the surface area decreased with the increasing amount of doped molybdenum. The oxidation catalytic behavior of xMo/PO4 3-/SiO2-TiO2 was evaluated through epoxidation of styrene using H2O2 as oxidant. Amongst, 5Mo/PO4 3-/ SiO2- TiO2was the best oxidative catalyst which gave the highest conversion of styrene and the highest yield of styrene oxide

Molybdena doped titania supported TUD-C as as oxidative catalyst for styrene epoxidation

Molybdena doped titania supported on TUD-C (Mo-TiO2/TUD-C) oxidative catalyst has been synthesized and characterized. The self assembled zeolite inside the silica matrices with MFI framework has been confirmed using XRD analysis. The attainment of zeolite and MFI structures was supported by FTIR results. Crystallinity of the synthesized material decreased with increasing Si/Al ratio in the TUDC due to the formation of amorphous silica. The crystallite size of the materials was 30 nm as evidenced by TEM analysis. Among the samples prepared, Mo-TiO2/TUD-C of Si/Ti = 10 and Si/Al = 10 showed the highest catalytic activity with styrene oxide yield and selectivity of 8.42 mmol and 97%, respectively at room temperature. The increase of both Si/Ti and Si/Al ratios in Mo-TiO2/TUD-C led to poor catalytic performance due to less availability of catalytic active sites. The catalytic performance of Mo-TiO2/TUD-C was 8- fold higher than that unsupported Mo-TiO2. Results strongly suggested that TUD-C played an important role as catalyst support for the homogenous dispersion of Mo-TiO2 active sites, leading to the enhanced catalytic performance of Mo-TiO2. It has been demonstrated that Mo-TiO2/TUD-C was a good oxidative catalyst for styrene epoxidation at room temperature with high conversion and selectivity towards styrene oxide

Tud-1 supported vanadium-doped titania photocatalyst

New photocatalyst of Techniche Universiteit Delft-1 (TUD-1) supported 5 mol% V doped TiO2 (5V-TiO2 /TUD-1) exhibited enhanced activity in methylene blue photodegradation. XRD results revealed the presence of both anatase and rutile phases in the V-doped TiO2 sample. After loading onto TUD-1, the crystallinity of the sample dropped significantly, implying well dispersion of both V and TiO2 on the TUD-1. DRUV-Vis results suggested alteration of Ti species in the presence of TUD-1. Besides, the band gap energy of V-doped TiO2 decreased after loading onto TUD-1. The sample 5V-TiO2 /TUD-1 possessed high surface area of 626 m2 /g. The photocatalytic performance of the sample was evaluated through the photodegradation of methylene blue under UV irradiation. It has been demonstrated that 5V-TiO2 /TUD-1 was a better photocatalyst compared to TUD-1 and unsupported V-doped TiO2 . The current findings strongly indicated that TUD-1 played an important role as support to improve the photocatalytic activity of V-doped TiO2

Novel visible light-driven photocatalyst of mesoporous tud-1 supported chromium oxide doped titania for phenol photodegradation

Novel visible light driven mesoporous photocatalysts of Technische Universiteit Delft-1 (TUD-1) supported 1 mol% Cr oxide doped TiO2 (Cr-TiO2) were synthesized. Low angle XRD and FTIR results confirmed the amorphous and mesoporous silicate framework of TUD-1 in the materials. The mesostructure was further confirmed via N2 adsorption-desorption analysis showing type IV isotherm with narrow average pore size distribution (2.5 nm) and high surface area (864 m2/g). TEM analysis results indicated the attainment of nanoparticles and the porous channels in the synthesized materials. An increase in band-gap energy was observed after loading of Cr-TiO2 into TUD-1. As compared to the unsupported Cr-doped TiO2, all the TUD-1 supported Cr-doped TiO2 photocatalysts showed higher photocatalytic activity for phenol degradation under visible light irradiation. Amongst, sample Cr oxide doped TiO2 supported on TUD-1 with molar ratio Si/Ti = 30 exhibited the highest photodegradation of phenol (82%). The phenol photodegradation followed the Langmuir adsorption isotherm with first order kinetics

Cr doped TiO2 supported on TUD-1 photocatalyst for dye photodegradation

New visible light driven photocatalysts of 1 mol% Cr doped TiO2 supported on TUD-1 have been successfully synthesized. The Cr-TiO2/xTUD-1 (x = 10, 20, 30, 40 and 50) photocatalysts were prepared via surfactant-free sol-gel method followed by wet impregnation procedures. XRD analysis revealed that both TiO2 and Cr were incorporated in the highly porous siliceous matrix. FTIR analysis showed the existence of Si-O-Ti in all the materials. As observed, tetrahedral-coordinated Ti species were dominant in Cr-TiO2/10TUD-1, Cr-TiO2/20TUD-1 and Cr-TiO2/30TUD-1. Meanwhile, octahedral- coordinated Ti species were the dominant species in Cr-TiO2/40TUD-1 and Cr-TiO2/50TUD-1. It has been demonstrated that the amount of TUD-1 as photocatalyst support affected the wavelength response and the bandgap energy of the resulting materials. All the materials have bandgap energy of ~2.9 eV. The photocatalytic performance of the synthesized materials was tested out in dye photodegradation under visible light irradiation at 298 K for 5 hours. Results showed that all Cr-TiO2/TUD-1 materials had higher photocatalytic activity than that of Cr-TiO2. This could be explained by the high surface area and porosity provided by TUD-1 in enhancing the adsorption and diffusivities of the dye molecules, hence leading to the promising photocatalytic activity. Among the materials prepared, Cr-TiO2/30TUD-1 appeared as the most superior photocatalyst which gave the highest dye photodegradatio

Comparison study on molybdena-titania supported on TUD-1 and TUD-C: properties and catalytic performance

A direct comparison between nanostructured Technische Universiteit Delft-1 (TUD-1) and Technische Universiteit Delft-Crystalline (TUD-C) as catalyst supports for molybdenum doped titania catalysts was carried out. The characterizations results showed that TUD-1 is a mesoporous amorphous silicate material with high surface area and porosity. Meanwhile, TUD-C is an ordered mesoporous crystalline aluminosilicate matters featured high acidity. In fact, TUD-C was obtained from the modification of TUD-1 with the addition of aluminium isopropoxide as the zeolite precursor. The catalytic testing demonstrated TUD-1 supported 1 mol% molybdena doped titania was inactive for epoxidation of 1,2-epoxyoctane and showed moderate activity (18%-21% conversion yield) and selectivity (approximately 70%) in epoxidation reaction of 1,2-epoxycyclohexane (0.51 mmol) and styrene oxide (1.25 mmol). Meanwhile, TUD-C supported 1 mol% molybdena doped titania achieved remarkably higher conversion yield for 1,2-epoxyoctane (2.7 mmol), 1,2-epoxycyclohexane (4.8 mmol) and styrene oxide (6.2 mmol) respectively with 100% selectivity towards all 3 analytes under ambient condition with constant stirring. The results strongly indicated that high Bronsted and Lewis acidic sites existed within the TUD-C framework is the key factor for the exceptional oxidative capabilities for molybdena-titania catalysts

Comparison study on Molybdena-Titania supported on TUD-1 and TUD-C synthesized via sol-gel templating method: properties and catalytic performance in olefins epoxidation

A direct comparison between nanostructured Technische Universiteit Delft-1 (TUD-1) and Technische Universiteit Delft-Crystalline (TUD-C) as catalyst supports for molybdenum doped titania catalysts was carried out. The characterizations results showed that TUD-1 is a mesoporous amorphous silicate material with high surface area and porosity. Meanwhile, TUD-C is an ordered mesoporous crystalline aluminosilicate matters featured high acidity. In fact, TUD-C was obtained from the modification of TUD-1 with the addition of aluminium isopropoxide as the zeolite precursor. The catalytic testing demonstrated TUD-1 supported 1 mol% molybdena doped titania was inactive for epoxidation of 1,2-epoxyoctane and showed moderate activity (18%-21% conversion yield) and selectivity (approximately 70%) in epoxidation reaction of 1,2-epoxycyclohexane (0.51 mmol) and styrene oxide (1.25 mmol). Meanwhile, TUD-C supported 1 mol% molybdena doped titania achieved remarkably higher conversion yield for 1,2-epoxyoctane (2.7 mmol), 1,2-epoxycyclohexane (4.8 mmol) and styrene oxide (6.2 mmol) respectively with 100% selectivity towards all 3 analytes under ambient condition with constant stirring. The results strongly indicated that high Bronsted and Lewis acidic sites existed within the TUD-C framework is the key factor for the exceptional oxidative capabilities for molybdena-titania catalysts

Properties and photocatalytic behaviour of vanadia loaded titania supported on mcm-41 synthesized using different surfactants for degradation of methylene blue

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