石墨烯复合金属离子掺杂纳米二氧化钛光催化材料的研究进展

对石墨烯复合金属离子掺杂纳米二氧化钛光催化材料在污染物治理、CO_(2)还原和资源化、H_(2)生产等方面的研究进展进行了论述。石墨烯复合金属离子掺杂纳米二氧化钛光催化材料相较于纳米二氧化钛,其禁带宽度变窄,提高了在可见光区的吸收性能,提高了光催化活性,提高了污染物降解率、CO_(2)还原和资源化的产率和H_(2)生产效率。

非金属离子掺杂纳米二氧化钛复合光催化材料降低水中污染物的研究进展

对非金属离子掺杂纳米二氧化钛复合光催化材料降低水中污染物的研究进展进行论述;非金属离子掺杂纳米二氧化钛复合光催化材料相较于纳米二氧化钛,其禁带宽度变窄,提高了在可见光区的吸收性能,提高了光催化活性,提高了污染物降解率。

石墨烯纳米二氧化钛复合光催化材料的应用研究进展

对石墨烯纳米二氧化钛复合光催化材料在污染物治理、CO_(2)还原和资源化、H_(2)生产等领域的应用研究进展进行了论述。与纳米二氧化钛相比,石墨烯纳米二氧化钛复合光催化材料的禁带宽度变窄,提高了在可见光区的吸收性能,提高了光催化活性和反应效率,提高了污染物的降解率,CO_(2)还原和资源化产率以及H_(2)生产效率也得到了提高。

纳米二氧化钛复合材料降解水中污染物的研究

对金属离子掺杂纳米二氧化钛复合光催化材料降低水中污染物的研究进展进行了论述;金属离子掺杂纳米二氧化钛复合光催化材料相较于纳米二氧化钛,其禁带宽度变窄,提高了在可见光区的吸收性能,提高了光催化活性,提高了污染物降解率。

可降解汽车尾气的沥青混合料开发及工程应用

针对城市汽车尾气所造成的空气污染问题,开发了纳米二氧化钛基光催化降解材料(WLSF-TiO 2),将其添加到薄层罩面沥青混合料中,并在北京市景山前街路面预防性养护工程中进行了应用。室内研究与对比评价表明,添加该材料后,沥青混合料的路用性能仍然满足规范要求,与普通二氧化钛基光触媒材料相比,其对汽车尾气中主要污染物(NO x、HC、CO)的降解效果提高约30%;实体工程应用检测结果表明,添加WLSF-TiO 2的路面,其路幅范围内汽车尾气中主要污染物降解效果可达10%左右。

Porous TiO2-coated Magnetic Core-Shell Nanocomposites：Preparation and Enhanced Photocatalytic Activity

The core-shell structured TiO2/SiO2 @Fe3O4 photocatalysts were prepared using Fe3O4 as magnetic core,tetraethoxysilane（TEOS） as silica source and tetrabutyl titanate（TBOT） as titanium sources.The as-obtained structure was composed of a SiO2@Fe3O4 core and a porous TiO2 shell.The diameter of SiO2@Fe3O4 core was about 205 nm with thickness of porous TiO2 of about 5-6 nm.The 9%TiO2/6%SiO2@Fe3O4 microspheres possess the highest BET surface area and the BJH pore volume,which are 373.5 m2.g-1 and 0.28 cm3.g-1,respectively.The 9%TiO2/6%SiO2@Fe3O4 photocatalyst exhibited an excellent performance for the degradation of methyl orange and methylene blue dyes.Two different dyes were completely decolorized in 60 min under UV irradiation.The photocatalytic activity and the amount of catalyst were almost not decrease after recycling for 6 times by using external magnetic field.

In-situ route for the graphitized carbon/TiO composite photocatalysts with enhanced removal efficiency to emerging phenolic pollutants

TiO2 is the most photoactive material because of its superstrong photooxidizing ability,and TiO2 photocatalysis has been widely applied in sustainable water treatment and environmental remediation.However,poor sunlight or visible-light harvesting efficiency and fast recombination rate of the photogenerated charge carriers severely limit the practical applications of TiO2.To overcome these problems,the present work demonstrates a facile in-situ co-condensation method combined with hydrothermal treatment to prepare a series of graphitized carbon/TiO2 composite photocatalysts,and anatase TiO2 phase andp-p-conjugated polycyclic aromatic carbon structure are created simultaneously.As-prepared TiO2/C composites exhibit remarkably high visible-light photocatalytic activity in the degradation of aqueous emerging phenolic pollutants,acetaminophen(APAP)and methylparaben(MPB),and apparent rate constant of the TiO2/C composite with carbon doping level of 10.3%for APAP and MPB removal is 7.6 and 2.8 times higher than that of bare TiO2,and 6.2 and 2.6 times higher than that of Degussa P25 TiO2.Based on the results of photoelectrochemical experiments,indirect chemical probe measurements,and ESR spectroscopy,it is verified that doping TiO2 with graphitized carbon is responsible for this enhanced photocatalytic activity,which renders the improved visible-light harvesting ability,the accelerated separation of the photogenerated charge carriers,and enlarged BET surface areas.Through analyzing the intermediates yielded in the photodegradation process,the pathway of visible-light photocatalytic degradation of APAP and MPB over the TiO2/C composite is proposed.

Increased photo-catalytic removal of sulfur using titania/MWCNT composite

Titania coating of multi wall carbon nano tube(MWCNT) was carried out by sol-gel method in order to improve its photo catalytic properties.The effect of MWCNT/TiO_2 mass to volume ratio on adsorption ability,reaction rate and photo-catalytic removal efficiency of dibenzothiophene(DBT) from n-hexane solution was investigated using a 9 W UV lamp.The results show that the addition of nanotubes improves the photo-catalytic properties of TiO_2 by two factors;however,the DBT removal rate versus MWCNT content is found to follow a bimodal pattern.Two factors are observed to affect the removal rate of DBT and produce two optimum values for MWCNT content.First,large quantities of MWCNTs prevent light absorption by the solution and decrease removal efficiency.By contrast,a low dosage of MWCNT causes recombination of the electron holes,which also decreases the DBT removal rate.The optimum MWCNT contents in the composite are found to be 0.25 g and 0.75 g MWCNT per 80 m L of sol.

Photocatalytic Characteristics of TiO2/Hangjin 2# Clay Composites

Composite photocatalyst of TiOg/Hangjin 2# clay has been used as a carrier for the composite photocatalyst due to its low cost prepared by acid-catalyzed sol-gel method. Hangjin 2# clay was and abundant reserves in Inner Mongolia, China. The samples were characterized by X-ray diffraction （XRD）, Fourier transformed infrared spectroscopy （FT-IR）, scanning electron microscopy （SEM） and Brunauer-Emmett-Teller （BET） specific surface area measurements. XRD patterns proved that anatase and rutile phases were coexisted with 52% anatase and 48% ruffle for the TiO2 in the composite. FT-IR analysis demonstrated that the insertion of TiO2 in composite photocatalyst did not destroy the basal framework structure of the clay. SEM results proved the addition of Hangjin 2# clay restrained TiO2 grain growth and the grain size in the composite was smaller than that of pure TiO2 in the same process. Photocatalytic characteristics of TiO2/Hangiin 2~ clay composites were evaluated by measuring degradation ratio of methylene blue （MB） in aqueous solution under ultraviolet （UV） irradiation. Effects of TiO2 wt%, gelling temperature and heat-treating temperature on the photocatalytic activity of the composites were investigated. The composite catalyst showed higher photocatalytic activity than the pure TiO2 under the same experimental conditions. In addition, the composite photocatalysts were easier to recover and reuse than pure TiO2 samples.

Improved performance and prolonged lifetime of titania-based materials: sequential use as adsorbent and photocatalyst

Lifetime is a key index in the evaluation of environmentally functional materials. Although it is well known that adsorption is the first step in photocatalysis, very little work has been done on the sequential use of materials as both adsorbents and photo- catalysts. In this work, two titania-based materials, TiO2 xerogel and TiO2 photocatalyst nanoparticles, were fabricated and evaluated as adsorbent and photocatalyst for the remediation of contaminated water with an azo dye, Acid Orange 7 （AO7）, as the modeling pollutant. The TiO2 xerogel showed a high adsorption capacity to AO7 （769 mg/g） and could be regenerated eas- ily with diluted NaOH solution （0.01 mol/L） for several cycles. The exhausted xerogel was calcined at 400 ℃ for 3 h and used as a photocatalyst for the degradation of AO7. Compared to the nanoparticles directly prepared from fresh TiO2 xerogel, the TiO2 nanoparticles from adsorption exhausted xerogel showed a much higher photocatalytic activity upon both UV and visible light irradiation. Thus the titania-based materials were endowed with improved performance as well as prolonged lifetime.

Synthesis of TiO_2 photocatalysts with abundant surface defects using a TiO_2@NaCl precursor

TiO2 nanoparticles have been synthesized by using a TiO2@NaCl core-shell structure as the precursor. The surface defects were well preserved by the NaCl shell, and therefore high oxygen adsorption capacity was observed. After the NaC1 shell was removed, the resulting pure TiO2 nanoparticles were of anatase phase and uniform size of around 20-24 nm. The presence of an abundance of surface defects contributes to the high photocatalytic activity of the synthesized materials, and the TiO： mate- rials obtained from the TiO2@NaCl precursor can be used as efficient photocatalysts for degradation of rhodamine B under UV light irradiation.

Controllable synthesis of titania/reduced graphite oxide nanocomposites with various titania phase compositions and their photocatalytic performance

A facile method is presented for preparing TiO2/reduced graphite oxide （RGO） nanocomposites with phase-controlled TiO2 nanoparticles via redox reaction between the reductive titanium （III） precursor and graphite oxide （GO）, and a series of TiO2/RGO composites with various TiO2 phase compositions were obtained. In all the titania/RGO composites, the TiO2 nanoparticles were uniformly distributed on the surface of the RGO. The TiO2 consisted of anatase phase particles in the form of square-plates with edges less than 10 nm and the rutile phase nanorods in diameters less than 10 nm. The performances of the as-prepared TiO2/RGO composites were investigated on catalytically degrading phenol under visible light irradiation. The TiO2/RGO composites can effectively degrade phenol under visible light irradiation, and the phase composition of TiO2 in the composites significantly influences the activities of these catalysts.

Photoactivity of titanium dioxide/carbon felt composites prepared with the assistance of supercritical carbon dioxide: Effects of calcination temperature and supercritical conditions

TiO2-coated carbon felt(TCF)composite catalysts have been prepared via a supercritical treatment of titanium tetraisopropoxide(TTIP)as the precursor.The physical properties of the catalysts were characterized by means of thermogravimetric and differential thermal analysis(TG–DTA),X-ray diffraction(XRD),fluorescence spectroscopy,scanning electron microscopy (SEM),and BET surface areas techniques.The photocatalytic activities of the materials were evaluated using the degradation of Congo red(CR)as a probe reaction.All the composites showed much higher photocatalytic activity than commercial P25 due to significant synergistic effects.Reused TCF retained high photocatalytic activity for degradation of CR.The photocatalytic efficiency in CR degradation was found to be strongly dependent on the TiO2-coating ratio and calcination temperature.A possible mechanism for the enhanced reactivity involves shuttling of electrons from TiO2 particles to the carbon felt(CF)as a result of an optimal arrangement in TCF that stabilizes charge separation and reduces charge recombination.In addition to the significant synergistic effects,the abundant spaces between adjacent carbon fibers allow UV light to penetrate into the felt-like photocatalyst to a considerable depth,so that a three-dimensional environment is available for the photocatalytic reaction.