钒酸铋光催化功能织物的制备及光降解活性蓝19的研究

以NH4VO3和(Bi NO3)3·5H2O为原料,采用低温原位合成法制备钒酸铋(Bi VO4)负载可见光光催化功能织物。考察反应溶液p H值、反应时间、反应温度对Bi VO4晶型结构及光吸收性能的影响。实验证明反应溶液p H、反应时间以及反应温度等影响因素对产物Bi VO4的晶型结构起着很重要的影响,90℃反应温度和中性条件下反应10h有利于单斜晶型Bi VO4的生成。用400W金卤灯模拟自然光中的可见光光源,选择印染中常用的C.I.活性蓝19(RB-19)为降解对象,模拟光源条件下研究功能织物的光催化功能活性。实验表明:Bi VO4负载光催化功能织物在模拟光源条件下对浓度为25mg/L的RB-19溶液在180min内降解率达到70%。     

冻干法制备Fe掺杂C_3N_4光催化降解有机污染物

采用冻干法制备Fe掺杂C_3N_4光催化剂,以X射线衍射(XRD)、表面吸附(BET),紫外-可见漫反射光谱(UV-Vis DRS)对催化剂的晶体结构、化学组成和光谱特性进行表征,在可见光照射下,用罗丹明B作为模拟污染物对催化剂的光催化性质进行测定.结果表明:采用冻干法制备的Fe掺杂C_3N_4光催化剂具有优异的光催化性能,采用冻干法制备的光催化剂比表面积较大,孔洞较多,具有较多的活性位点,是提高光催化活性的主要因素.     

可见光活性TiO_2的制备与表征

以TiOSO4和氨水为原料通过化学沉淀法制备了具有可见光活性的纳米Ti—O—N光催化剂,并采用SEM,BET,XRD,UV-vis,ESR和XPS等检测方法对其性能进行表征,通过甲基橙溶液降解实验研究了光催化剂在可见光下的光催化活性,讨论了比表面积、可见光吸收强度、晶型结构等因素对其光催化活性的影响.所制得的纳米Ti—O—N光催化剂经热处理后可以较强吸收波长范围为400～600 nm的可见光,且可见光吸收强度与粉体的热处理温度密切相关.光催化测试表明：经400℃热处理的光催化剂对可见光的吸收最强,且具有相对较大的比表面积和发育较为完整的晶型结构,因此在可见光下表现出最好的光催化活性.     

神府煤掺杂的光催化剂表征及对大港减渣的解聚

利用X射线衍射分析(XRD),比表面积分析(BET),透射电镜分析(TEM),紫外可见光分析(UV-vis)等对神府煤掺杂的二氧化钛(12％ SFC-TiO2)光催化剂进行了表征,并与自制的二氧化钛(TiO2),氮掺杂二氧化钛(15％N-TiO2),铁氮共掺杂二氧化钛(0.6％Fe-15％N-TiO2)和钴掺杂二氧化钛(1.5％ Co-TiO2)催化剂进行了比较,结果发现,神府煤掺杂的光催化剂为锐钛型纳米颗粒,其光学活性要高于二氧化钛、氮掺杂二氧化钛和铁氮共掺杂二氧化钛;将其应用于降解大港减渣(DVR),结果表明,在经该催化剂光催化氧化后的DVR产物中,含氧化合物相对含量高达92.43％,正构烷烃含量降为2.30％;在氧化产物中的最长碳链(C26)远小于原样中的最长碳链(C36),说明SFC-TiO2光催化氧化降解大港减渣是有效的.     

三维立体石墨烯/多孔黑色TiO2复合材料的制备及其光催化性能

采用水热还原法制备黑色多孔TiO_2(PBT)。以PBT和氧化石墨烯为原料,经一步水热合成三维立体石墨烯(RGO)/PBT。通过XRD、SEM、TEM、BET以及DRS等对复合材料的物相、颗粒粒径、形貌及比表面积进行了表征,研究了该复合材料在可见光下对罗丹明B(RhB)的光催化降解活性。结果表明,Ti~(3+)的存在大大提高了可见光的吸收;所制备的RGO/PBT复合材料的可见光催化活性均高于PBT;当RGO掺杂量为1%时制备的催化剂具有最高的光催化性能。     

超声条件下制备氮掺杂TiO2及其光催化活性研究

为拓展二氧化钛对可见光的响应,超声条件下采用溶胶凝胶法以三乙胺为氮源制备出N掺杂的纳米TiO2光催化剂;以甲基橙的光催化降解为探针反应,评价其光催化活性;运用XRD、TEM、XPS和UV-Vis DRS等技术考察了超声及N掺杂对TiO2微晶尺寸、晶体结构、表面组成与光学性能的影响.结果表明,所制备N掺杂TiO2为纯锐钛矿型,超声抑制了光催化剂粒晶的增大,减弱了颗粒间的硬团聚;N掺杂使TiO2光谱响应波长拓宽至可见光区,有效改善了TiO2的可见光活性,对甲基橙溶液的降解速率比纯TiO2提高了69.9%.     

La掺杂Bi2O3的制备及其可见光催化降解4-氯酚的研究

采用醇介导法制备了La离子掺杂改性的氧化铋,并通过SEM、IR、PL、BET、XRD等对其结构和性能进行表征.结果表明:L a离子掺杂导致氧化铋的禁带宽度由2.984 eV降低为2.940 eV,加大了氧化铋的光吸收范围并降低了光生电子-空穴的复合几率.掺杂La提高了Bi2 O3的可见光催化活性,在25℃可见光下4-氯苯酚光照8h的降解率可达92.24％.此外,控制实验表明空穴是La-Bi2 O3可见光催化降解4-氯苯酚的主要活性物种.     

P、V共掺杂纳米TiO_2的制备和性能研究

采用溶胶-凝胶法(Sol-gol)制备了P、V共掺杂的纳米TiO2光催化材料,借助XRD、紫外-可见光谱仪对制备的光催化材料进行表征,并通过晶粒尺寸、晶相结构和吸收光谱等分析,研究了P、V共掺杂对TiO2性能的影响。研究结果表明:P、V共掺杂抑制了TiO2由锐钛矿向金红石的转变,明显延缓了TiO2相的转移;P、V双掺杂可明显减小晶粒尺寸,增大催化剂的比表面积,无论掺杂与否,随着煅烧温度的升高,TiO2晶粒的尺寸变大,比表面积减小。从紫外-可见光谱图上发现,P/V共掺杂TiO2样品与其余样品相比,红移效果最明显,对可见光吸收能力最强。     

稀土修饰TiO2光催化降解甲基橙反应机理

采用溶胶-凝胶法制备纯的及掺杂不同量Ce的TiO2纳米粒子,利用UV-Vis漫反射光谱及XRD等对所制备样品进行表征,以紫外灯为光源,甲基橙水溶液的脱色为模型反应,研究了CeO2/TiO2的光催化降解反应活性.实验发现:掺杂Ce的TiO2纳米粒子反射光谱特性向可见光方向红移到了500nm;掺杂Ce的TiO2纳米粒子比纯的TiO2纳米粒子对光的吸收率高、吸收能力强;掺杂的Ce4+仅有少量进入TiO2晶格中,而大部分的Ce4+没有进入TiO2晶格中,而是以小团簇的CeO2形态均匀地分散在TiO2纳米粒子中或者是覆盖在其表面上,说明了掺杂Ce能提高TiO2光催化反应活性,且掺杂Ce最佳浓度是2.0mol%.光催化降解反应机理可能有两种途径,一种途径是掺杂离子协同光催化降解甲基橙反应机理,另一种途径是光敏剂与掺杂离子协同光催化降解甲基橙反应机理.     

N、S共掺杂TiO_2的制备及光催化性能

采用两步水热法制备N、S共掺杂的介孔二氧化钛粉末,并对所制备的样品采用比表面积(BET)、X射线(XRD)、扫描电镜(SEM)、UV紫外可见光谱等测试对晶型、形貌及光催化性能进行了表征,结果表明:通过水热法制备的二氧化钛粉末颗粒比较均匀,掺杂后的二氧化钛粉末降解率达到了98%以上。     

Fabrication of BiVO<Subscript>4</Subscript>: Effect of structure and morphology on photocatalytic activity and its methylene blue decomposition mechanism

BiVO₄ photocatalysts were synthesized by a surfactant free hydrothermal method without any further treatments, and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), ultraviolet-visible diffuse reflectance spectroscopy (UV-vis DRS), Raman spectroscopy, and Brunauer-Emmett-Teller (BET) surface area techniques. The photocatalytic activity was evaluated for the degradation of the methylene blue (MB) under visible light irradiation. Seen from the structural and morphological characterization, it is stated that the obtained samples present monoclinic phase, and the pH value has significant influence on the morphologies. The enhanced photocatalytic performance was associated with its crystallinity, unique morphology, band gap energy, BET specific surface area, surface charge and adsorption capacity. The recycle experiments results show that the BiVO₄ photocatalysts have excellent photo-stability, and we deduced a possible mechanism by examining the effects of the active species involved in the photocatalytic process for MB photocatalytic degradation.     

Preparation of V-doped TiO2 photocatalysts by the solution combustion method and their visible light photocatalysis activities

A series of nanocrystalline V-doped （0.0-3.0 at.%） TiO2 catalysts have been successfully prepared by the one-step solution combustion method using urea as a fuel. The obtained powders were characterized by XRD, SEM, Raman, XPS and UV-Vis DRS. The effects of V doping concentration on the phase structure and photocatalytic properties were investigated. XRD, Raman, and XPS show that V doping diffuses into TiO2 crystal lattice mainly in the form of V5＋ and causes a phase transition from anatase to mille. V doping can widen the light absorption range of TiO2, with the absorption threshold wavelength shifting from 425 to 625 nm. The photocatalytic activity of V-doped TiO2 powders were evaluated by the photocatalytic degradation of methyl orange （MO） under visible light irradiation. It is found that V doping enhances the photoeatalyilc activity under visible light irradiation and the optimal degradation rate of MO is about 95.8% with 1.0 at% V-doped TiO2.     

Photocatalytic activity of Mo+Fe Co-doped titanium dioxide nanoparticles prepared by Sol-Gel method

Mo+Fe co-doped TiO2 nano powders were synthesised by sol-gel method. X-ray diffraction and transmission electronic microscopy morphologies showed that the Mo+Fe co-doped TiO2 nano powders were pure anatase phase, with the average crystallite size around 20 nm. UV-Vis and photocatalic activity measurements show that this Mo+Fe co-doped TiO2 can absorb visible light, have higher separation efficiency of photoinduced electrons and holes, and possess higher photocatalytic activity compared with anatase TiO2. The enhanced photocatalytic activity of Mo+Fe co-doped TiO2 verified that doping by transition metal ions can also modify the energy band and reduce the recombination centers in TiO2.     

Photocatalytic activity of lanthanum and sulfur co-doped TiO<Subscript>2</Subscript> photocatalyst under visible light

A novel lanthanum and sulfur co-doped TiO2 photocatalyst was synthesized by precipitation- dipping method, and characterized by X-ray diffraction（XRD）, transmission electron microscopy（TEM） and UV-Vis diffuse reflectance spectroscopy. Compared with the S-doped TiO, La-doped TiO2 and the standard Degussa P25 photocatalysts, the lanthanum and sulfur co-doped TiO2 photocatalyst （the molar percentage of La is 3.0%） calcined at 450 ℃ for 2 h showed the strongest absorption for visible light and highest activities for degradation of reactive blue 19 dye in aqueous solution under visible light（λ〉400 nm） irradiation. It was also discovered that the co-doping of lanthanum and sulfur hindered the aggregation and growth of TiO2 particles, and the doping of lanthanum reduced slightly the phase transition temperature ofTiO2 from anatase to rutile.     

Preparation, Characterization and Visible Light Photocatalytic Activity of Nitrogen-doped TiO2

The N-doped TiO2 polycrystalline powder was synthesized through calcining the hydrolysis prodact of tetra-butyl titanate with ammonia. The photocatalytic activity of N-doped TiO2 powder with anatase phone calcined at 400℃ was 2.7 times higher than that of Degussa P25 for phenol decomposition under visible light. All samples had mesoporoas structures. X- ray photoelectron spectroscopy confirmed that a trace amount of N atoms remained in the anatase polycrystaUine TiO2 powder when calcined at 400 ℃ as substitutional atoms at the oxygen sites. UV-Vis and EPR analyses indicated that oxygen vacancy states were created during the course of N-doped TiO2 powder formation. It is considered that substitutional N atoms, oxygen vacancy, states, large BET surface areas and mesoporoas structure are important facwrs for the N-doped photocatalyst to present a high vis-activity.     

沸石负载Mn,N共掺杂TiO2及光催化性能

为提高传统TiO₂光催化剂的可见光催化活性,本文采用溶胶-凝胶法合成了Mn,N共掺杂TiO₂光催化剂,改善了传统TiO₂光生载流子易复合的问题;进一步采用沸石作为载体对改性后的TiO₂样品进行负载,解决了传统光催化剂存在的难分离回收问题,以达到光催化剂可重复使用的目的.借助X-射线衍射仪、扫描电子显微镜、紫外分光光度计、傅立叶变换红外光谱仪等测试手段对Mn,N共掺杂TiO₂光催化剂的结构、元素组成、微观形貌和光催化降解性能进行系统分析与研究.研究结果表明,沸石负载Mn,N共掺杂TiO₂的样品较未改性的TiO₂样品具有更高的光催化降解活性,在可见光照射下,在最优掺杂条件下获得的TiO₂光催化剂在60 min内对孔雀石绿的降解率可达到97%,这主要归因于锰离子掺杂能够对TiO₂光生载流子的复合产生抑制作用,促进光生电荷分离,与此同时氮元素掺杂可有效拓宽TiO₂半导体光催化剂光响应范围.此外,经过5次循环使用后,对孔雀石绿的降解率没有较大程度的减弱,依然能够维持在88%以上,表明沸石负载Mn,N共掺杂TiO₂的样品具有较好的光催化循环稳定性.     

Co掺杂ZnO纳米结构材料的水热制备及性能研究

以乙酸锌为原料、乙酸钴为掺杂剂,采用水热法制备得到了Co掺杂氧化锌纳米结构材料,并通过X-射线衍射(XRD)、扫描电镜(SEM)、紫外-可见漫反射光谱(DRS)等测试手段对所得产物的性能进行了研究。XRD的分析结果表明Co的掺杂并未改变氧化锌本体的晶型结构;SEM照片显示了Co的不同掺杂量对样品形貌有较大影响;DRS结果说明Co的引入有助于提高可见光区的吸收强度,并可使得其带隙宽度E_g在3.25～2.85 eV之间进行调节。     

La和Zn共掺杂改性纳米TiO_2光催化剂的制备及表征

采用沉淀法-水热法相结合的方法分别制备未掺杂、La3+与Zn2+单掺杂及共掺杂的Ti O2光催化剂。通过SEM、XRD和UV-vis DRS等对样品形貌、结构和光吸收进行了表征,并以甲基橙溶液为目标降解物考察了掺杂纳米Ti O2粉体的光吸收和光催化性能。结果表明,La3+与Zn2+共掺杂后样品在紫外和可见光区的吸收能力显著提高,光吸收发生明显红移,吸收边波长为446 nm;La3+、Zn2+掺杂降低了光生电子-空穴对的复合率,光催化活性明显提高,光照20 min后,La/Zn/Ti O2对甲基橙的降解率高达99%。     

二硫化物修饰改性乙炔加氢催化剂研究

以正硅酸乙酯和双-(3-(三乙氧基硅)丙基)-二硫化物通过溶胶凝胶法制备的S2-SiO2为载体,再通过浸渍法合成了新型负载型钯催化剂,并研究了该催化剂对乙炔气相催化加氢制备乙烯的催化活性、转化率及选择性,而且采用FTIR、UV-Vis、TG和BET对催化剂的结构进行了表征。结果表明,催化剂对乙炔催化加氢制乙烯反应具有良好的催化性能,当钯负载量为0.6%时,反应温度达到140℃,乙炔转化率达到100%,乙烯选择性可达到90%以上;FTIR结果表明合成含配体的SiO2载体;BET表征结果显示添加配体后的催化剂比表面积明显增大;TG分析结果表明配体修饰负载型Pd催化剂的分解温度为378℃,反应温度要低于此温度;UV-Vis DRS结果显示配体与Pd产生了相互作用。     

YVO_4基纳米光催化剂制备及其光催化脱汞性能评价

采用水热反应法制备YVO4光催化剂,并通过掺杂C和Sm3+对其进行改性,通过X射线衍射仪(XRD)、扫描电镜(SEM)和比表面积(BET)对其形态、结构、组成和性质进行表征.在紫外光条件下,对YVO4及其改性后的催化剂进行脱除气态元素汞(Hg0)评价,YVO4,YVO4掺碳,YVO4掺Sm3+,YVO4掺Sm3+掺碳催化剂脱汞效率分别为10.5%,9.1%,5.2%,19.6%.其中YVO4∶Sm3+/C效果最好,但也只有19.6%.这可能是紫外光激发了YVO4导带的电子,且电子成功地跃迁到了价带,但由于此反应产生的光生载流子能量较弱,不足以激发自由·OH,只能靠光生载流子直接氧化汞,导致样品不能高效光催化氧化汞.