稀土掺杂TiO2光催化还原CO2

采用溶胶-凝胶法制备了稀土掺杂TiO₂纳米光催化剂,并应用于光催化还原CO₂/H₂O体系中。通过XRD对光催化性能进行表征,研究稀土离子掺杂和焙烧温度对光催化性能的影响。结果表明,稀土La和Ce的加入可以抑制TiO2的晶相转变,提高光催化性能。催化剂800 ℃焙烧可达到最好的光催化活性,在反应时间7 h、CO₂流量200 mL·min^-1和反应液中NaOH与Na₂SO₃浓度均为0.10 mol·L^-1条件下,甲醇产率高达315.49 μmol·g^-1。并对稀土掺杂TiO₂催化剂光催化还原CO₂的机理进行了探究。     

掺杂铁纳米TiO2的制备及其光催化性能研究

分别采用水热法和溶胶-凝胶法制备了纳米级TiO₂和不同掺铁量的TiO₂纳米粒子。通过纯TiO₂和掺铁TiO₂分别作光催化剂时甲基橙溶液在紫外光下的光催化降解试验发现，溶胶-凝胶法掺杂铁离子可以有效地提高TiO₂光催化活性，而水热法掺杂铁使TiO₂的光催化活性明显降低。Fe/TiO₂摩尔比为0.01％～0.1％，随掺杂量的增大,TiO₂光催化活性逐渐降低。     

稀土氢氧化物纳米线掺杂二氧化钛光催化性能

利用水热法合成稀土Y(OH)3和Eu(OH)3纳米线,取一定稀土纳米线掺入以钛酸四丁酯为主要原料的溶胶-凝胶体系中,制备出不同煅烧温度不同稀土掺杂量的TiO2材料。以甲基橙为目标降解物,研究了该材料的光催化性能。结果表明,稀土的掺入量对材料的光催化性能有明显的影响,甲基橙的脱色率随着稀土掺入量的增加降低;不同煅烧温度也影响材料的光催化性能,实验条件下,煅烧温度较高的材料催化甲基橙的脱色率更高,当煅烧温度为600℃,Y(OH)3或Eu(OH)3纳米线掺入量为1%时,光催化效果最佳,光反应1 h后甲基橙的降解率可达99%以上。     

稀土镨掺杂TiO2光催化剂的吸附和光催化活性研究

通过溶胶-凝胶法成功地制备了一系列Pr3掺杂的TiO2光催化剂,并通过X射线衍射(XRD)、紫外-可见吸收(DRS)对催化剂进行了表征,结果表明所制催化剂为锐钛矿型,Pr3+的掺杂有利于抑制晶粒生长,提高晶体的热稳定性.DRS光谱证实,Pr3+的掺杂增强了催化剂在可见光区域的吸收能力.吸附实验结果表明,Pr3+的掺杂显...     

稀土掺杂纳米TiO2光催化剂制备及其光催化性能

采用溶胶-微波法制备掺杂不同稀土元素纳米TiO2光催化剂,借助XRD和UV-Vis吸收光谱等手段对其进行表征.以甲基橙为模拟污染物,考察样品的光催化性能.结果表明,适量的La3+、Nd3+、Eu3+、Gd3+和Y3+掺杂可提高TiO2样品的光催化活性,最佳掺杂物质的量分数分别为0.1%、0.1%、0.3%、0.2%和0...     

Alkaline earth metal doped nanoporous TiO2 for enhanced photocatalytic mineralisation of bisphenol-A

Magnesium and barium doped TiO₂ nanoparticles were synthesised by sol-gel technique. The materials were characterised by XRD, BET, UV-Vis, FT-IR, SEM and TEM techniques. The pure TiO₂ nanoparticles gave both anatase and rutile phases together, but the presence of either Mg²⁺ or Ba²⁺ metal ion in TiO₂ gave only anatase phase. The framework substitution of Mg²⁺ in TiO₂ was established by XRD and FT-IR techniques. However, Ba²⁺ was retained only on the surface of TiO₂ as BaCO₃ and the absence of framework substitution of Ba²⁺ in TiO₂ was evident from XRD and FT-IR analysis. The band gap values of Mg²⁺ and Ba²⁺ doped nano TiO₂ were higher than the parent nano TiO₂. The photocatalytic activity in the degradation of bisphenol-A was found to be higher for metal doped nano TiO₂ than both pure nano TiO₂ and commercial TiO₂ (Degussa P-25).     

稀土掺杂ZnO光催化降解偏二甲肼废水研究

利用水热法制备稀土掺杂ZnO/La3+、ZnO/Ce3+、ZnO/Y3+纳米颗粒,用于光催化降解偏二甲肼废水。结果表明,掺杂ZnO颗粒大小均匀,直径在100～200 nm,纯度高。2 h后,对30 mg/L偏二甲肼废水的最大降解率分别为80.4%,82.3%,67.8%,降解率较纳米复合ZnO平均提高80%以上。     

One-dimensional spindle-like BiVO4/TiO2 nanofibers heterojunction nanocomposites with enhanced visible light photocatalytic activity

One-dimensional spindle-like BiVO₄/TiO₂ nanofibers heterojunction nanocomposites with high visible light photocatalytic activity have been successfully obtained by combining the electrospinning technique and solvothermal method. The as-obtained products were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV–vis spectra and photoluminescence (PL) spectra. The results revealed that spindle-like BiVO₄ nanostructures were successfully grown on TiO₂ nanofibers. Photocatalytic tests showed that the BiVO₄/TiO₂ nanofibers heterojunction nanocomposites showed enhanced visible light photocatalytic activity than that of pure TiO₂ nanofibers, which might be attributed to the effective photogenerated electrons-holes separation based on the photosynergistic effect of the BiVO₄/TiO₂ heterojunction. Moreover, the BiVO₄/TiO₂ nanofibers heterojunction nanocomposites could be easily recycled without any decrease of the photocatalytic activity.     

Enhanced photocatalytic activity of electrospun TiO2/ZnO nanofibers with optimal anatase/rutile ratio

The photocatalytic characteristics of the TiO₂/ZnO nanofibers synthesized by electrospinning followed by calcinating at different temperatures to alter the anatase-to-rutile ratio are investigated. The results demonstrate that the photocatalytic activity of TiO₂/ZnO nanofibers is enhanced by optimizing the anatase/rutile ratio among the trade-off effects of the band-gap energy, the electron/hole recombination rate, and the surface area. When calcined at 650 °C, the TiO₂/ZnO nanofibers with optimal anatase/rutile ratio (48:52) balancing these trade-off effects have the highest photocatalytic efficiency both in the degradation of RhB in liquid and conversion of NO gas.     

Fabrication of TiO2 nanofibers assembled by Bi2WO6 nanosheets with enhanced visible light photocatalytic activity

A series of Bi₂WO₆/TiO₂ nanofibers (BT NF) hierarchical photocatalysts were synthesized by a facile two-step strategy consisting of electrospinning technique and subsequent solvothermal method. The results showed that the secondary two-dimensional Bi₂WO₆ nanosheets were uniformly assembled onto the surface of the TiO₂ NF. It was also verified that the density of Bi₂WO₆ nanosheets could be tailed by controlling the precursor concentration during the solvothermal process. Photocatalytic tests demonstrated that BT NF with a low concentration of precursor (S1) possessed a much higher visible light degradation rate for Rhodamine B than TiO₂ NF, Bi₂WO₆ and their mixture. The enhanced photocatalytic activity of S1 was ascribed to the extension of the light absorption region induced by the introduction of narrow band gap Bi₂WO_6, and the formation of heterojunction accelerating the interfacial charge separation. Moreover, BT NF with a high concentration of precursor (S2) manifested a higher photocatalytic activity than S1 due to the higher loading of Bi₂WO₆ nanosheets. S2 could be reused by sedimentation, and the photocatalytic activities of S2 were retained with a slight decline after four cycles, which confirmed its stability. Therefore, BT NF composites will be ideal candidates for highly efficient and recyclable photocatalysts for the treatment of organic pollutants under visible light.     

Gd~(3+)掺杂TiO_2纳米纤维的制备、表征及其光催化性能

采用静电纺丝技术并结合溶胶-凝胶方法制备TiO2和TiO2/Gd2O3纳米纤维,采用差热-热重分析(TG-DTA)?场发射扫描电镜(FE-SEM)、红外光谱(FTIR)、X射线粉末衍射(XRD)对材料进行表征,通过亚甲基蓝光降解反应研究其催化性能。结果表明,掺杂Gd3+可以强烈抑制TiO2由锐钛矿相向金红石相的转变,抑制晶粒生长,减少晶粒尺寸;Gd3+掺杂TiO的纳米纤维对亚甲基蓝的光催化活性明显提高。     

Titanium dioxide modified with transition metals and rare earth elements: Phase composition,optical properties,and photocatalytic activity

A series of titania–transition metal and titania–rare earth element mixtures, with the stoichiometry Ti_1−xM_xO₂, where M=Ce, Eu, La, Nb, W, Y, and x ranging from 0 to 0.05 atoms per formula unit, were prepared via solid-state reaction of the precursor oxides. The products of the synthesis were thermally treated in air and two maximum temperatures (900 and 1000 °C) were reached.     

Synthesis of three-dimensional ordered macroporous TiO2, Gd/TiO2 and their photocatalytic activity

In this paper, three-dimensional ordered macroporous (3DOM) TiO₂ and Gd/TiO₂ materials were synthesized by colloidal crystal templating process. The obtained samples were analyzed by field-emission scanning electron microscope, transmission electron microscopy, X-ray diffraction, diffuse reflectance spectra and Brunauer–Emmett–Teller method. The photocatalytic activity of various samples was evaluated by degradation of methyl orange in aqueous solution under UV and visible light irradiation. At the same time, Degussa P25 (a commercial Titania) powders were used for comparison. The results indicated that 3DOM Gd/TiO₂ samples showed a significant shift in the onset absorption towards the longer wavelength compare to pure 3DOM TiO₂, and displayed excellent photocatalytic activity under both UV and visible light irradiation.     

稀土元素Pr掺杂对ZnO材料结构及光催化性能的影响

采用溶胶-凝胶法制备了稀土元素Pr掺杂的纳米ZnO光催化剂,利用XRD、SEM、EDS及亚甲基蓝降解实验对样品的结构与性能进行了表征和测试。研究表明,与纯ZnO相比,掺杂Pr能有效促进ZnO的晶粒细化,稀土元素Pr以Pr_2O_3化学态形式高度分散在ZnO表面,增加了催化剂表面氧空位,改变了ZnO的晶格缺陷和光吸收范围,明显提高了ZnO的光催化性能。在摩尔比n(Pr)∶n(ZnO)=0.03∶0.97时,制得样品Zn_(0.97)Pr_(0.03)O的光催化性能最好,紫外灯照射150 min后,对亚甲基蓝的降解率为94.5%,比纯ZnO的降解效率提高了32.5%,对苯酚溶液和间苯二酚溶液的降解效率分别为82.2%,91.5%。     

稀土元素Pr掺杂对ZnO材料结构及光催化性能的影响

采用溶胶-凝胶法制备了稀土元素Pr掺杂的纳米ZnO光催化剂,利用XRD、SEM、EDS及亚甲基蓝降解实验对样品的结构与性能进行了表征和测试。研究表明,与纯ZnO相比,掺杂Pr能有效促进ZnO的晶粒细化,稀土元素Pr以Pr_2O_3化学态形式高度分散在ZnO表面,增加了催化剂表面氧空位,改变了ZnO的晶格缺陷和光吸收范围,明显提高了ZnO的光催化性能。在摩尔比n(Pr)∶n(ZnO)=0.03∶0.97时,制得样品Zn_(0.97)Pr_(0.03)O的光催化性能最好,紫外灯照射150 min后,对亚甲基蓝的降解率为94.5%,比纯ZnO的降解效率提高了32.5%,对苯酚溶液和间苯二酚溶液的降解效率分别为82.2%,91.5%。     

微波水热法制备稀土元素铒掺杂TiO_2光催化剂及光催化活性

采用微波水热法和溶胶-凝胶法制备稀土元素Er掺杂TiO_2光催化剂TiO_2-Er,以甲基橙溶液为模拟污染物,在微波辐射-紫外光照(MW-UV)和太阳光照条件下,考察TiO_2-Er光催化剂的光催化降解活性。分别用N_2吸附-脱附、ICP-AES和PL光谱分析对TiO_2-Er光催化剂进行结构测试和表征。结果表明,Er掺杂能显著提高TiO_2光催化剂光催化活性,微波水热法制备的TiO_2-Er光催化剂具有较高的光催化活性;微波水热法和溶胶-凝胶法制备的TiO_2-Er光催化剂微波辐射-紫外光照50 min,甲基橙降解率分别为100%和98.5%,太阳光照4 h,甲基橙降解率分别为99.0%和97.5%。微波水热法具有晶化时间短和元素掺杂均匀的优点,制备的TiO_2-Er光催化剂具有形貌均匀、孔径较大、孔分布均匀和比表面积较大等特点,且Er掺杂能抑制光生e~-/h~+复合,使光生e~-/h~+的分离效率得到提高,有利于光催化活性的提高。     

铈和锰掺杂纳米TiO2的溶胶-凝胶法制备及其光催化性能

采用溶胶-凝胶法制备了TiO₂、Mn⁴⁺/TiO₂、Ce⁴⁺/TiO₂和Mn⁴⁺-Ce⁴⁺/TiO₂光催化剂。通过考察掺杂离子的种类和用量对所得催化剂用于紫外光催化降解甲基橙性能的影响，表明Ce⁴⁺/TiO₂中Ce⁴⁺的适宜掺杂量为1.0%，Ce⁴⁺-Mn⁴⁺/TiO₂中，当Mn4+的掺杂量为25.0%时，Ce⁴⁺的适宜掺杂量为0.50%，相应的脱色效率为92.39%和99.41%。当掺杂量适当时，四种催化剂用于紫外光催化降解甲基橙的活性次序为：Mn⁴⁺-Ce⁴⁺/TiO₂ > TiO₂>Ce⁴⁺/TiO₂> Mn⁴⁺/TiO₂。XRD分析结果表明，所得光催化剂均为锐钛矿型纳米粒子。     

TiO2 and TiO2/Ag nanofibers: template synthesis,structure, and photocatalytic properties

Journal of Porous Materials - A fairly simple method for the synthesis of TiO2 and TiO2/Ag fibers containing the anatase–rutile-silver heterojunction with a combination of features attractive...     

纳米TiO2光催化材料离子掺杂的正电子湮没研究

采用正电子湮没技术研究了13种金属离子掺杂对纳米TiO₂光催化材料缺陷的影响,并讨论了离子掺杂对TiO₂光催化材料平均电子密度和光催化活性的影响。结果表明,纳米TiO₂光催化材料的缺陷主要是氧空位、孪晶界、位错和金属空位等。正电子湮没谱的分析表明,Fe³⁺、W⁶⁺和La³⁺高价态离子的掺杂降低纳米TiO₂的平均电子密度,低价态的Zn²⁺、Cu²⁺、Pb²⁺、Mn²⁺、Co²⁺和Ag⁺掺杂增大了纳米TiO₂的平均电子密度,Al³⁺、V⁵⁺、Ni²⁺和Cr³⁺的掺杂对纳米TiO₂平均电子密度没有影响。纳米TiO₂的离子掺杂寿命谱与光催化活性之间关系分析表明,Pb²⁺、La³⁺、Cr³⁺和Co²⁺掺杂时,材料中自由体积缺陷的形成不利于TiO₂光催化活性的提高,而Fe³⁺、W⁶⁺、La³⁺、Cu²⁺、Mn²⁺、Ag⁺、Al³⁺、V⁵⁺和Ni²⁺掺杂时,则有利于TiO₂光催化活性的提高。     

The effects of atmosphere and calcined temperature on photocatalytic activity of TiO2 nanofibers prepared by electrospinning

TiO₂-based nanofibers were synthesized using a sol–gel method and electrospinning technique. The as-spun composite fibers were heat-treated at different temperatures (500°C, 550°C, 600°C, and 650°C) and atmospheres (ammonia and nitrogen) for 4 h. The fibers had diameters of 50 to 200 nm and mainly featured anatase and rutile phases. The anatase phase decreased and the rutile phase increased with increasing temperature. Different nitrogen conditions exerted minimal effects on the TiO₂ crystalline phase. Different nitriding atmospheres during preservation heating yielded various effects on fibers. The effect of nitrogen in ammonia atmosphere is better than that in nitrogen atmosphere. The fibers heat-treated at 600°C and subjected to preservation heating in NH₃ showed high photocatalytic activity.