Preparation, Characterization, Photocatalytic Activity of S and Ag co-Doped Mesoporous Titania Photocatalysts

In order to improve the photocatalytic performance of mesoporous titania under visible light, a series of photocatalysts of S and Ag co-doped mesoporous titania have been successfully prepared by template method using thiourea, AgNO3 and tetrabutyl titanate as precursors and Pluronic P123 （EO20PO70EO20） as template. Scanning electron microscopy （SEM）, X-ray diffraction （XRD）, nitrogen adsorption-desorption measurements, and UV-visible spectroscopy （UV-Vis） were employed to characterize the morphology, crystal structure, surface structure, and optical absorption properties of the samples. The microcrystal of the photocatalysts consisted of anatase phase and was approximately present in the form of spherical particle. The photocatalytic performance was studied by photodegradation methyl orange （MO） in water under UV and visible light irradiation. The calcination temperature and the doping content influenced the photoactivity. In addition, the possibility of cyclic usage of co-doped mesoporous titania was also confirmed, the photocatalytic activity of mesoporous titania remained above 89% of that of the fresh sample after being used four times. It was shown that the co-doped mesoporous titania could be activated by visible light and could thus be potentially applied for the treatment of water contaminated by organic pollutants. The synergistic effect of sulfur and silver co-doping played an important role in improving the photocatalytic activity.

Synthesis and Characterization of Mesoporous Titania Particles and Thin Films

Well-organized mesoporous titania particles and thin films were successfully synthesized by using tetrabutyl titanate as the inorganic precursor and triblock copolymer （Pluronic P123） as the template via evaporationinduced self-assembly process. The resulting materials were characterized by high resolution transmission electron microscopy （HRTEM）, X-ray diffraction （XRD）. Fourier-transform infrared spectroscopy （FT-IR）,Brunauer-Emmett-Teller （BET） and atomic force microscopy （AFM）. Macro shape of mesoporous titania would greatly influence the mesostructure of materials, and the probable reasons were also discussed.

Preparation of mesoporous titania particles using ionic liquid dissolving starch as templates

A mesoporous titania photocatalyst was prepared via calcining the solution of ionic liquid （1-methyl-3-butyl imidazolium bromide, [BMIM]Br） containing tetrabutyl titanate （TBT） and starch. The microstructure of the prepared mesoporous titania was characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, and N2 adsorption/desorption isotherm. The results indicate that the resulting mesoporous titania has a grain size of about 13.9 nm, a special surface area of 106 m2/g, and a pore volume of 0.22 cm3/g, and the pore size can be adjusted by the concentration of starch in ionic liquid. The photocatalytic activity of mesoporous titania in the degradation of methyl orange solution was determined. The effect of the specific surface area of mesoporous titania on the photocatalytic activity was also studied. The prepared mesoporous titania exhibits a high catalytic activity.

Double diamond structured bicontinuous mesoporous titania templated by a block copolymer for anode material of lithium-ion battery

Titania has received considerable attention as a promising anode material of Li-ion battery(LIB).Controlling the structure and morphology of titania nanostructures is crucial to govern their performance.Herein,we report a mesoporous titania scaffold with a bicontinuous shifted double diamond(SDD)structure for anode material of LIB.The titania scaffold was synthesized by the cooperative self-assembly of a block copolymer poly(ethylene oxide)-block-polystyrene template and titanium diisopropoxide bis(acetylacetonate)as the inorganic precursor in a mixture solvent of tetrahydrofuran and HCl/water.The structure shows tetragonal symmetry(space group I4_(1)/amd)comprising two sets of diamond networks adjoining each other with the unit cell parameter of a=90 nm and c=127 nm,which affords the porous titania a specific surface area(SSA)of 42 m^(2)·g^(-1)with a mean pore diameter of 38 nm.Serving as an anode material of LIB,the bicontinuous titania scaffold exhibits a high specific capacity of 254 mAh·g^(-1)at the current density of 1 A·g^(-1)and an alluring self-improving feature upon charge/discharge over 1,000 cycles.This study overcomes the difficulty in building up ordered bicontinuous functional materials and demonstrates their potential in energy storage application.

Preparation and characterization of visible-light-driven europium doped mesoporous titania photocatalyst

pure and different content europium （Eu） doped mesoporous titania were prepared by template method using Eu（NO3）3·6H2O and Ti（OC4H9）4 as precursors and Pluronic P123 as template and characterized with X-ray diffraction （XRD）, N2 adsorption-desorption measure- ments, and ultraviolet-visible diffuse absorption spectra. Their photocatalytic activities were studied by photodegradation phenol in water un- der visible light irradiation. The results showed that Eu doping restrained the growth of grain size and extended the photoabsorption edge of mesoporous titania into the visible light region, which made Eu-doped mesoporous titania possess high photocatalytic activity under visible light. In the experiment condition, the photocatalytic activity of 0.2 mol.% Eu doped mesoporous titania was optimal of all the prepared samples.

Transition metal doped mesoporous titania with a crystalline framework as catalysts for oxidation of p-bromotoluene to pbromobenzaldehyde

Transition metal M(M=Mn,Fe,Co,Ni,Cu,and Zn)doped mesoporous titania with a crystalline framework was employed as catalysts for the oxidation of p-bromotoluene(PBT)to p-bromobenzaldehyde(BBD)in acetic acid using aqueous hydrogen peroxide as oxidant.It was found that mesoporous TiO_(2) doped with those metals(Fe,Co and Ni)whose atomic radii are relatively smaller exhibited higher conversion rate of PBT.Among these catalysts,the Co/meso-TiO_(2) exhibited high substrate conversion and good product(p-bromobenzaldehyde)selectivity plus it can be reused once with almost the same activity.The effect of different Ti/Co(molar)ratio on the activities of Co/meso-TiO_(2) was also investigated.

Effects of Template Contents on the Physicochemical Sorption Properties of Zr-Incorporated Mesoporous Titania Materials

Zr-Incorporated mesoporous titania materials were prepared via nonsurfactant templated sol-gel process of zirconium (IV) butoxide (ZBT) and titanium (IV) butoxide (TBT) in the presence of urea molecules as template or pore forming agent. The effects of template contents on the pore parameters of the materials synthesized with fixed Zr incorporation contents were investigated by nitrogen adsorption-desorption measurements, powder X-ray diffraction (XRD) study and transmission electron microscopy (TEM). The changes of template contents play significant roles on the pore parameters at low incorporation content of Zr. The pore diameters display a clear increase tendency with the increase of template contents. When high Zr incorporation content is used, the template contents have less effect on the pore diameters that almost keep unchanged with the increase of template contents. All the materials possess type IV isotherms with H 2 hysteresis loops suggesting the formation of mesophase. The materials with low Zr incorporation content have anatase structures; however, it can not be found in the materials with high Zr incorporation content. TEM images show that some accumulated inter-particulate pores and well-distributed worm-like pores are present in the Zr-incorporated materials.

In-situ synthesized mesoporous TiO_2-B/anatase microparticles:Improved anodes for lithium ion batteries

Mesoporous TiO_2-B/anatase microparticles have been in-situ synthesized from K_2Ti_2O_5 without template.The TiO_2-B phase around the particle surface accelerates the diffusion of charges through the interface,while the anatase phase in the core maintains the capacity stability.The heterojunction interface between the main polymorph of anatase and the trace of TiO_2-B exhibits promising lithium ion battery performance.This trace of 5%(by mass) TiO_2-B determined by Raman spectra brings the first discharge capacity of this material to 247 mA · h ·g^(-1),giving 20%improvement compared to the anatase counterpart Stability testing at 1 C reveals that the capacity maintains at 171 mA·h·^(-1),which is better than 162 mA·h·g^(-1) for single phase anatase or 159 mA·h·g^(-1) for TiO_2-B.The mesoporous TiO_2-B/anatase rnicroparticles also show superior rate performance with 100 mA·h·g^(-1) at 40 C,increased by nearly 25%as compared to pure anatase.This opens a possibility of a general design route,which can be applied to other metal oxide electrode materials for rechargeable batteries and supercapacitors.

Size controllable synthesis and photocatalytic performance of mesoporous TiO2 hollow spheres

Hollow mesoporous TiO2 spheres(THs)were prepared via template-directed deposition of TiO2 nanoparticles on the surface of carbon spheres.The carbon spheres were used as hard templates.Their diameters were controlled by pH adjustment prior to a hydrothermal process.Physical properties,such as crystallinity,optical characteristics,microstructure and surface morphology of the samples were characterized.The results showed that the diameter of the carbon template could be well controlled in the range of 397-729 nm by adjusting the initial pH value of the dextrose solution from 3 to 10.Hollow TiO2 spheres with average diameters ranging from 171 to 668 nm and shell thicknesses ranging from 28 to 47 nm formed by heat treatment at 450℃.The photocatalytic performance of hollow TiO2 spheres and TiO2 nanoparticles was examined under UVA irradiation using a methyl orange aqueous solution as an artificial dye.The study revealed that the THs synthesized using a dextrose solution at pH 7 had a higher photocatalytic activity compared to other samples since it had the lowest shell thickness and the proper optical band gap of 3.12 eV with the longest lifetime of electron-hole pair separation.

Lanthanide complexes-functionalized ordered mesoporous TiO_2:Multicolor emission(visible and near-infrared luminescence) based on visible-light sensitization

Recently,much attention has been paid to the lanthanide luminescent materials based on the visiblelight sensitization for their potential applications in the fields of bio-imaging and optical devices.In this work,the lanthanide complexes have been covalently bonded to the ordered mesoporous titania（OMT） matrix,and the resulting titania-based hybrid ordered mesoporous materials（named as LnDBOMT,Ln = Eu,Sm,Yb,Nd） were characterized by using Fourier-transform infrared（FT-IR） spectroscopy,small-angle X-ray powder diffraction（SAXD）,N2 adsorption-desorption isotherms,transmission electron microscopy（TEM）,fluorescence spectroscopy,and thermogravimetric analysis.Generally,exciting with visible light is advantageous over UV excitation.Of importance here is that,under excitation with visible light,the LnDB-OMT all show characteristic visible（Eu3＋,Sm3＋） as well as nearinfrared（Sm3＋,Yb3＋,Nd3＋） luminescence of the corresponding Ln3＋ ions（multicolor emission covered from 500 to 1400 nm spectral region）,which is attributed to the energy transfer from the ligands to the Ln3＋ ions via an antenna effect.

Facile and controllable preparation of mesoporous TiO2 using poly（ethylene glycol） as structure-directing agent and peroxotitanic acid as precursor

This work demonstrated that mesoporous TiO= （meso-TiO2） with con- trollable mesoporous and crystalline structures can be facilely prepared by using poly （ethylene glycol） （PEG） as structure-directing （SD） agent and peroxotitanic acid （PTA） as precursor. Meso-TiO2 with high specific surface area （157 m2.g-1）, pore volume （0.45 cm3.g-1） and large mesopore size of 13.9 nm can be obtained after calcination at 450℃. Such meso-TiO2 also shows relatively high thermal stability. BET surface area still reaches 114 m2-g-1 after calcination at 550℃. In the synthesis and calcination process, PEG that plays multiple and important roles in delivering thermally stable and tunable mesoporous and crystalline structures shows to be a suitable low-cost SD agent for the controllable preparation of nanocrystalline meso-TiO2. The photocataiytic activity tests show that both high surface area and bi-crystallinity of obtained meso-TiO2 are important in enhancing the performance in photo-decomposing Rhodamine B in water.

Metabolic Molecular Diagnosis of Inflammatory Bowel Disease by Synergistical Promotion of Layered Titania Nanosheets with Graphitized Carbon

Due to inefficient diagnostic methods,inflammatory bowel disease(IBD)normally progresses into severe complications including cancer.Highly efficient extraction and identification of metabolic fingerprints are of significance for disease surveillance.In this work,we synthesized a layered titania nanosheet doped with graphitized carbon(2D-GC-mTNS)through a simple one-step assembly process for assisting laser desorption ionization mass spectrometry(LDI-MS)for metabolite analysis.Based on the synergistic effect of graphitized carbon and mesoporous titania,2D-GC-mTNS exhibits good extraction ability including high sensitivity(<1 fmolμL−1)and great repeatability toward metabolites.A total of 996 fingerprint spectra were collected from hundreds of native urine samples(including IBD patients and healthy controls),each of which contained 1220 m/z metabolite features.Diagnostic model was further established for precise discrimination of patients from healthy controls,with high area under the curve value of 0.972 and 0.981 toward discovery cohort and validation cohort,respectively.The 2D-GC-mTNS promotes LDI-MS to be close to clinical application,with rapid speed,minimum sample consumption and free of sample pretreatment.

Synthesis and characterization of super paramagnetic composite photocatalyst-Titania/silica/nickel ferrite

Composite photocatalysts with TiO2 porous shell and magnetic core were synthesized by using NiFe2O4 as a magnetic core, SiO2 as an intermediate layer and polyethylene glycol with molecular weight of 1000 （PEG 1000） as a template direction agent. The samples were characterized with N2 adsorption-desorption, X-ray diffraction （XRD）, transmission electron microscopy （TEM）, scanning electron microscopy （SEM）, vibrating sample magnetometry （VSM） and ultraviolet-visible （UV-vis） spectroscopy. The results showed that the obtained composites are spherical particles about 50 nm in diameter. The mesoporous TiO2 with magnetic core calcined at 350 ℃, 450 ℃, and 550 ℃ was found to have, respectively, different specific surface areas （94, 86, and 68 m^2/g） and average pore sizes （1.4, 2.2, and 2.8 nm）. The photocatalytic activity was investigated for degradation of nitrobenzene under UV irradiation. Nitrobenzene was decomposed in 300 min under irradiation of an 8 W UV lamp with a peak wavelength of 253.7 nm. The composite nanoparticles exhibited high photocatalytic efficiency and super paramagnetic nature for cleaning polluted water by magnetic separation.