Catalytic activity of TiO2 nanoparticles in the synthesis of some 2,3-disubstituted dihydroquinazolin-4（1H）-ones

Green chemistry is playing an important role for synthesizing organic compounds, due to its eco-friendly nature and low cost. In green chemistry, metal nanoparticles exhibited some useful physical and chemical properties （catalytic activity）. Due to its diverse properties, nanoparticles can be utilized as a catalyst in various organic reactions. Recent research has been directed towards the utilization of eco- friendly and bio-friendly plant materials in nanoparticles synthesis. In our present work, TiO2 nanoparticles （TiO2 NPs） were synthesized using Annona squamosa peel extract and their catalytic applications were studied on the 2,3-disubstituted dihydroquinazolin-4（l1H）-one synthesis. Synthesized compounds were confirmed using FT-IR.1H NMR, 13C NMR and GC-MS analyses.     

Magnetically recoverable Cu2O/Fe3O4 composite photocatalysts：Fabrication and photocatalytic activity

A magnetically separable Cu2O/Fe3O4 magnetic composite photocatalyst was synthesized in large quantities by a fast and simple route. The as-prepared photocatalysts were characterized by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray photoelectron spectroscopy （XPS） and X-ray diffraction （XRD）. Furthermore, the Cu2O/Fe3O4 composite photocatalysts were tested using methyl orange （MO） degradation reaction under visible light irradiation （100 mW/cm2） and demonstrated to have a high photocatalytic efficiency toward the decomposition of MO under visible light irradiation with good recyclability.     

Synthesis and photocatalytic properties of core–shell TiO~2@ZnIn_2S_4 photocatalyst

A novel core–shell TiO2@ZnIn2S4composite has been synthesized successfully by a simple and flexible hydrothermal route using TiO2as precursors.The as-synthesized samples were characterized by X-ray diffraction,UV–vis diffuse reflectance spectra and transmission electron microscopy.The photocatalytic properties of samples were tested by degradation of aqueous methylene blue（MB）under visible light irradiation.It was found that the as-synthesized TiO2@ZnIn2S4photocatalyst was more effcient than TiO2and ZnIn2S4in the photocatalytic degradation of MB.Moreover,TEM images confrmed the TiO2@ZnIn2S4nanoparticles possessed a well-proportioned core–shell morphology.     

Photocatalytic Activities for Water Splitting of RuO_2-loaded MGa_2O_4（M=Zn,Ni） with d~（10） Configuration

MGa2O4(M=Zn,Ni) rods with similar crystallinity and BET surface area were prepared via a facile template-engaged reaction.The photocatalytic activities for water splitting of RuO2-loaded MGa2O4(M=Zn,Ni) were investigated under high-pressure Hg lamp.RuO2-loaded ZnGa2O4 catalyst exhibited much higher photocatalytic activity than RuO2-loaded NiGa2O4.Factors affecting the photocatalytic activities of RuO2-loaded MGa2O4(M=Zn,Ni) were discussed.It was suggested that the electronic structure of oxide semiconductor was a predominant factor of the photocatalytic behavior for RuO2-loaded MGa2O4(M=Zn,Ni).     

Synthesis of TiO2/ZnSn（OH）6 Hollow Nano-composite via a Simultaneous Crystallization-etching Route as Photocatalyst

We report the synthesis of TiO2/ZnSn（OH）6 as a novel nano-composite material via a simultaneous crystallization-etching route with cubic nano-ZnSn（OH）6 and TiF4 as the precursors. The structure, composition and morphology of the composite were characterized by XRD, EDS, FETEM and FESEM, which showed the prepared TiO2/ZnSn（OH）6 had a unique morphology of hollow cubic nano-ZnSn（OH）6 attached with rutile TiO2 nanoparticles. The results of photocatalytic activity measurement indicated the photocatalytic activity of the prepared composite was better than that of nano-ZnSn（OH）6. This study may be helpful for the design and fabrication of functional comoosite materials.     

Study on the Synthesis of La（3）-doped Nano-TiO_2 and Photocatalytic Degradation of Methyl Orange

In this paper,La(3)-doped Nano-TiO2(La(3)-TiO2) was synthesized via hydrothermal process.Structure and optical properties of the synthesized samples were characterized via XRD,FT-IR,DRS,etc.The results showed that the phase transformation of TiO2 from anatase to rutile was effectively prevented by La(3)-doping,which improved the thermal stability of anatase,and also suppressed particle aggregation and grain growth of TiO2.The formation of Ti-O-La bond promoted UV absorption intensity of TiO2,and provoked red shift of absorbed light.And the spectra response range of TiO2 was extended significantly to visible light by La(3)-doping,then photocatalytic performance was improved effectively.Compared with pure nano-TiO2,the performance of La(3)-TiO2 which photocatalyticly degraded methyl orange was increased significantly.     

Flame synthesis of TiO2 nanoparticles with high photocatalytic activity

Growth behaviour of TiO₂ particles, which has significant influence on their crystallinity and surface area, has been controlled by varying the process parameters of the flame aerosol synthesis. An existing method to determine the crystallinity of the powder has been modified which facilitates comparison of the degree of crystallinity of the nanoparticles synthesized by various methods. Resultant TiO₂ nanoparticles were characterized by XRD and nitrogen physisorption to determine the degree of crystallinity quantitatively and surface area, respectively, and the decomposition rate of an industrial dye, methylene blue, has been taken as the measure of the photocatalytic activity (PCA). TiO₂ nanoparticles showed improved photocatalytic activity compared to the commercial photocatalyst, Degussa P25. This is attributed to the increased degree of crystallinity and surface area of the TiO₂ nanoparticles compared to Degussa P25. The results of this study elucidate the importance of the gas-phase processes and strategy to synthesize highly active TiO₂ photocatalysts in a single step. Moreover, difference in the PCA of the nanoparticles synthesized by the similar gas-phase routes has been shown and the particles are tailor-made for improved PCA in the present study.     

Synthesis and study of Bi2Ti2O7/TiO2 composites as efficient visible-light-active photocatalysts in the reduction of aqueous Cr(VI)

In this work, Bi_2Ti_2O_7/TiO_2 composites were synthesized and studied as potential visible-light-activated photocatalysts in the reduction of aqueous Cr(VI). Bi_2Ti_2O_7/TiO_2 composites with tunable compositions were synthesized via a solvothermal-calcination two-step method, simply by changing the molar ratios of Bi(NO_3)_3·5H_2O to tetrabutyl titanate in the reactants. The compositions, structures and optical properties of the as-synthesized Bi_2Ti_2O_7/TiO_2 composites were characterized by X-ray diffraction, field emission scanning electron microscopy and UV–vis diffuse reflectance spectra. The photocatalytic activity of the as-synthesized Bi_2Ti_2O_7/TiO_2 composites was tested in the reduction of aqueous Cr(VI)under visible-light(λ420 nm) irradiation, and compared with that of TiO_2 nanoparticles. It was observed that the as-synthesized Bi_2Ti_2O_7/TiO_2 composites exhibited much higher photocatalytic activity than TiO_2 nanoparticles, and the most efficient composite(300 mg) can achieve the complete reduction of Cr(VI) in 300 mL of 50 mg/L K_2Cr_2O_7 aqueous solution under visible-light(λ420 nm)irradiation in 90 min.     

One-step synthesis of nanocrystalline N-doped TiO2 powders and their photocatalytic activity under visible light irradiation

Nanocrystalline N-doped TiO₂ powders were successfully prepared by hydrothermal reaction for 2 h at low temperature (120 °C) and at an applied pressure of 3 MPa. The grain size of the powders (calculated by use of Scherrer’s method) ranged from 8.2 to 10.2 nm. The BET specific surface area ranged from 151.0 to 220.0 m²/g. A significant shift of the light absorption edge toward the visible light zone was observed in the UV–visible spectra. XPS results showed that nitrogen atoms were incorporated into the TiO₂ lattice. The photocatalytic activity of the synthesized N-doped TiO₂ powders was evaluated by measurement of photodegradation of methylene blue (MB) in aqueous solution under visible light irradiation. The amount of MB degraded increased with increasing illumination intensity.     

Template-free synthesis of mesoporous N-doped SrTiO(3) perovskite with high visible-light-driven photocatalytic activity

An effective, template-free synthesis methodology has been developed for preparing mesoporous nitrogen-doped SrTiO(3) (meso-STON) using glycine as both a nitrogen source and a mesopore creator. The N-doping, large surface area and developed porosity endow meso-STON with excellent activity in visible-light-responsive photodegradation of organic dyes.     

高纯纳米氧化钛的制备及催化活性

以工业级硫酸钛为原料,在酸性环境下以EDTA作为络合剂,采用控制沉淀法制备高纯度纳米TiO2。考察了pH值、反应温度、煅烧温度等工艺条件对TiO2颗粒晶型、大小和分布影响。利用TEM、XRD、ICP等手段对产物进行表征,TiO2纯度超过99.9%,粒径为10-20nm,分布均匀。经过对其光催化降解苯酚反应活性实验,结果表明样品具有较好的光催化活性。     

Microwave-assisted synthesis of CdS-reduced graphene oxide composites for photocatalytic reduction of Cr(VI)

CdS-reduced graphene oxide (RGO) composites are successfully synthesized via the microwave-assisted reduction of graphite oxide in a CdS precursor solution using a microwave synthesis system. The photocatalytic performances of CdS-RGO composites in the reduction of Cr(VI) are investigated. The results show that CdS-RGO composites exhibit enhanced photocatalytic performance for the reduction of Cr(VI) with a maximum removal rate of 92% under visible light irradiation as compared with pure CdS (79%) due to the increased light absorption intensity and the reduction of electron-hole pair recombination in CdS with the introduction of RGO.     

TiO2/EDTA-rich carbon composites: Synthesis,characterization and visible-light-driven photocatalytic reduction of Cr(VI)

TiO₂/EDTA-rich carbon composites exhibits excellent photoreduction of Cr(VI) activity via ligand-to-metal charge transfer process.     

Synthesis of TiO2 on different substrates by chemical vapor deposition for photocatalytic reduction of Cr(VI) in water

TiO₂ loaded on several substrates such as carbon fiber, aluminum plate, silica plate, and glass plate was prepared using the chemical vapor deposition (CVD) method for the photocatalytic reduction of Cr(VI) in water with the presence of ethanol under Ultraviolet (UV) illumination. As‐prepared samples were characterized by X‐Ray Diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET), and scanning electron microscopy (SEM). The catalyst with TiO₂ loaded on carbon fiber possessed an extremely large surface area (1,463,91 m²/g), while the other catalysts possessed small surface areas (0.05–0.21 m²/g). The photocatalytic activity of TiO₂ loaded on carbon fiber, which was determined by the conversion of Cr(VI) and the degradation of chemical oxygen demand (COD), was much higher than that of other catalysts. The reusability of TiO₂ loaded on carbon fiber catalyst exhibited almost the same activity as the fresh catalyst. The results indicated that TiO₂ loaded on carbon fiber is feasible for practical application.     

A novel Fe（OH）3/TiO2 nanoparticles and its high photocatalytic activity

A very simple and controllable approach was proposed to synthesize novel Fe(OH)_3/TiO_2 nanoparticles.Compared with neat TiO2,the Fe(OH)_3/TiO_2 increased the rate of the photocatalytic degradation of methyl orange at pH 6.0 by more than five times, showing photocatalytic activity as excellent as P25.This enhancing effect is mainly attributed to the ferric hydroxide deposits as the electron scavenger and the enriched surface hydroxyl groups.