W掺杂BiOCl光催化剂的制备及其可见光催化性能研究

在以Bi(NO3)3为铋源、WCl6为氯源和钨源、乙二醇为溶剂、尿素为添加剂形成的新Bi-W-Cl-O体系下采用一步溶剂热法合成W掺杂BiOCl光催化剂,应用XRD、FSEM、XPS和UV-Vis对样品进行表征,并以苯气体作为降解物,考察了W掺杂BiOCl光催化剂的光催化性能。结果表明,由于金属W的掺杂,BiOCl的吸收波长发生明显红移,相比于纯BiOCl提高了对太阳光的利用率,同时大大提高了BiOCl在可见光下的光催化降解苯效率。     

纳米钼酸铋/偕胺肟纤维光催化剂的制备及性能研究

以Bi(NO3)3和Na2Mo O4为原料,偕胺肟纤维作为配体,采用液相法合成钼酸铋/偕胺肟纤维(Bi2Mo O6/AOCF),通过X射线粉末衍射(XRD)、扫描电子显微镜(SEM)、能谱(EDS)对样品进行了表征分析。结果显示,颗粒状的Bi2Mo O6均匀分布在纤维表面,并以配位键的形式与纤维结合。以罗丹明B(Rh B)为模拟污染物来考察Bi2Mo O6/AOCF的光催化活性,实验表明,Bi2Mo O6/AOCF有着很好的光催化活性,并且在酸性条件下的催化活性更好。催化剂对活性黄、亚甲基蓝和甲基橙也表现出较好的光催化活性,且重复使用5次后对Rh B的降解率仍可以达到91.4%。光催化反应过程符合一级反应动力学。     

前驱物中Mo(Ⅵ)浓度对h-MoO3的制备及其光催化性能的影响

以分析纯钼酸铵 《NH4)6Mo7O24 ·4H2O)和硝酸(HNO3)为原料,采用水热法制备了六方相结构的h-MoO3微晶.通过X射线衍射和扫描电子显微镜分别对在不同Mo(Ⅵ)浓度的钼酸铵溶液中所制备产物的物相组成、显微结构进行了分析.并以亚甲基蓝染料为目标降解物,评价了不同Mo(Ⅵ)浓度制备的h-MoO3微晶的光催化性能.结果表明:无模板剂条件下,当Mo(Ⅵ)浓度为0.04～0.60 mol/L时均可合成单一物相、六方棒状结构的h-MoO3微晶,且随着Mo(Ⅵ)浓度提高,棒的尺寸逐渐增大.在可见光照射下,Mo(Ⅵ)浓度为0.07 mol/L时制备的h-MoO3样品的光催化降解亚甲基蓝的效果最明显,在光照100min后光催化降解率达到了99.7％.     

Bi_2MoO_6和Bi_2WO_6材料的合成和光催化性能研究

本课题利用水热法一步合成了钼酸铋(Bi_2Mo O_6)和钨酸铋(Bi_2WO_6)两种半导体光催化剂。借助红外光谱(IR)、X射线衍射光谱(XRD)和扫描电子显微镜(SEM)对样品的物相结构、表面结构进行了表征。以罗丹明B为目标降解物,借助太阳光为光源,研究了两种催化剂材料在不同光催化时间下对有机染料的光催化性能影响。结果表明,纳米片结构的Bi_2WO_6对有机染料的降解综合性能要优越于纳米线团簇结构的Bi_2Mo O_6材料,尤其是Bi_2WO_6催化剂对罗丹明B染料的降解度在光催化5小时后可以达到80%。     

Lu/Bi_2WO_6光催化剂的制备及其降解含酚废水的性能

采用水热合成法制备了Lu/Bi_2WO_6光催化剂。通过XRD、SEM、XPS、UV-vis DRS、PL等手段对所制备的材料做了结构表征,并以苯酚溶液为目标污染物研究了材料的光催化降解含酚废水的活性。实验结果表明:在Bi~(3+)与W~(6+)的物质的量比为2∶1、前驱液pH=1、水热反应温度为120℃、水热反应时间为20 h、Lu的掺杂量为5%(物质的量分数)的最优条件下,制得的Lu/Bi_2WO_6光催化剂是由花球状微纳米颗粒组成的材料,在300 W汞灯照射6 h下,对20 mg/L的苯酚溶液的降解率达到98.5%,比Bi_2WO_6纯样品的降解效率提高了40%左右。     

BiOBr/g-C3N4光催化剂的制备及其LED紫光光催化活性

以五水硝酸铋、溴化钾和三聚氰胺为原料,采用溶剂热法制备了摩尔比不同的BiOBr/g-C3N4复合光催化剂,并进行了XRD、SEM和DRS表征分析.以50 W LED紫光灯为光源,采用罗丹明B为目标降解物考察了制备样品的光催化性能.结果表明:摩尔比为1∶1的BiOBr/g-C3N4复合光催化剂的具有最优的光催化性能.机理实验结果表明:超氧自由基(O2·-)和空穴(h+)为BiOBr/g-C3N4复合光催化剂光催化过程最为主要的活性物种.     

GO/TiO_2复合材料的制备和光催化性能研究

以钛酸丁酯为钛源,少层氧化石墨烯为GO源,通过溶剂热法和煅烧法合成GO/TiO_2催化剂。在300W氙灯照射下,以甲基橙为降解对象,探究不同制备方法、GO掺杂比例、用量的催化剂对光催化降解效率的影响。结果表明,当甲基橙初始浓度为10 mg/L,投加0.50 g/L煅烧法制备的0.8%GO/TiO_2催化剂时光催化效果最好,高达93.8%,且光催化反应符合一级动力学方程,其光催化降解的速率常数为1.090 h~(-1)。     

W掺杂的大孔-介孔TiO_2光催化剂的制备及性能研究

以聚苯乙烯(PS)微球为硬模板,聚醚P123为介孔导向剂,采用溶剂蒸发自组装法(EISA)制备了有序大孔-介孔W-TiO2薄膜。考察了金属W的掺杂量对光催化性能的影响。结果表明,大孔-介孔结构和W掺杂可以显著提高Ti O2薄膜材料在可见光区域的光催化活性,Ti与W的摩尔比为100∶4时,光催化活性最高,光催化降解5 mg/L罗丹明B,60 min降解完全。     

外围带不同基团的金属卟啉对4-硝基苯酚的光催化降解性能

合成了3种外围带有不同基团(甲氧苯基、羟苯基、烟酸酰氧苯基)的卟啉衍生物,并分别用3种不同金属离子(Cu~(2+)、Zn~(2+)、Fe~(3+))对它们进行金属化,考察了这9种金属卟啉对水溶液中4-硝基苯酚(4-NP)的光催化降解活性。结果表明,光催化降解活性由外围基团和中心金属离子共同决定,外围基团为烟酸酰氧苯基、中心金属离子为Fe~(3+)的金属卟啉(FeTNPP)的光催化降解活性最高;以H_2O_2作氧化剂,光照4h4-NP即可被完全降解。     

W掺杂的大孔-介孔TiO_2光催化剂的制备及性能研究

以聚苯乙烯(PS)微球为硬模板,聚醚P123为介孔导向剂,采用溶剂蒸发自组装法(EISA)制备了有序大孔-介孔W-TiO2薄膜。考察了金属W的掺杂量对光催化性能的影响。结果表明,大孔-介孔结构和W掺杂可以显著提高Ti O2薄膜材料在可见光区域的光催化活性,Ti与W的摩尔比为100∶4时,光催化活性最高,光催化降解5 mg/L罗丹明B,60 min降解完全。     

Molten Salt Synthesis, Characterization, and Luminescence Properties of Gd2MO6:Eu3+ (M=W, Mo) Phosphors

Large-scale micro- and nano-sized Eu³⁺-doped gadolinium tungstate and molybdate Gd₂MO₆:Eu³⁺ (M=Mo, W) red phosphors with special morphologies have been successfully prepared via an efficient molten salt synthesis (MSS) method at 950°C for 6 h using NaCl and as the reaction medium. The results of X-ray powder diffraction patterns indicate that Gd₂MoO₆ and Gd₂WO₆ have monoclinic structures. The scanning electronic microscope and transmission electron microscope studies revealed that the samples of Gd₂WO₆:Eu³⁺ and Gd₂MoO₆:Eu³⁺ phosphors obtained by the MSS method in NaCl medium have a sphere-like morphology, and the corresponding samples obtained in KCl medium have rod-like morphologies. For the Gd₂MoO₆:Eu³⁺ phosphor obtained in NaCl and KCl media, the sphere-like particles had an average grain size of ∼100 nm, and the size of the rod-like particles ranged from 200 to 400 nm in length, and ∼150 nm in width, respectively. Compared with the same products obtained by the solid-state reaction we had reported, the luminescent properties of Gd₂MO₆:Eu³⁺ (M=Mo, W) are largely dependent on their morphology and crystal size prepared using different fluxes of NaCl and KCl. The reaction time and temperature also play an important role in the crystallization of the samples.     

AgBr/Zn3(OH)2V2O7·2H2O可见光催化降解亚甲基蓝溶液

采用水热和沉淀两步合成法制备AgBr/Zn₃(OH)₂V₂O₇·2H₂O催化剂,研究其在可见光下降解亚甲基蓝溶液的性能,并考察催化剂用量、亚甲基蓝溶液初始浓度、pH值以及盐浓度对光催化性能的影响,评价AgBr/Zn₃(OH)₂V₂O₇·2H₂O催化剂的重复使用性能。结果表明,在前驱液pH为10、120 ℃水热10 h、Ag与Br物质的量比为0.20条件下制备的复合催化剂在可见光下反应120 min后,1.0 g·L^-1的催化剂对10 mg·L^-1的亚甲基蓝溶液脱色率达到85.2%。NaCl对亚甲基蓝的降解起抑制作用,Na₂SO₄对亚甲基蓝的降解起促进作用。催化剂重复使用4次后,光照120 min后的亚甲基蓝溶液脱色率可达66.4%。催化剂对不同初始浓度亚甲基蓝溶液的光催化降解符合一级动力学模型。     

C_3N_4-BiVO_4复合光催化剂可见光催化降解甲基橙

采用水热合成法制备C_3N_4-BiVO_4复合光催化剂,以甲基橙为目标污染物,研究催化剂用量、甲基橙溶液初始浓度和pH值、NaCl用量对甲基橙脱色率的影响,并通过C_3N_4-BiVO_4复合光催化剂的循环使用实验,考察其重复使用性能。结果表明,在甲基橙初始浓度20 mg·L~(-1)、复合光催化剂用量3.0 g·L~(-1)及弱酸性条件下,光照反应6 h,目标污染物甲基橙脱色率达98.81%,溶液中的NaCl对催化剂降解甲基橙有抑制作用。催化剂重复使用5次后,溶液脱色率约80%,表明催化剂性能较稳定,可重复使用。     

V2O5-WO3-MoO3/TiO2催化剂用于NH3选择性还原减排NOx的性能（英文）

The V2O5-WO3-MoO3/TiO2 honeycomb catalyst was prepared with industrial grade chemicals. The structural and physico-chemical properties were analyzed with X-ray diffraction (XRD), scanning electron micrograph (SEM) and mercury porosimetry. The NOx conversion and durability were investigated on a pilot plant test set under the actual operational conditions of a coal fired boiler. The catalyst monolith had good formability with mass percentage of V:W:Mo:TiO2 :fiber glass= 1:4.5:4.5:72:18. Vanadium, tungsten and molybdenum species were highly dispersed on anatase TiO2 without causing the transformation of anatase TiO2 to rutile by calcining under a current of air at 450℃ for 4.5 h, but there were some degrees of crystal distortion. The catalyst particle sizes were almost uniform with close pile-up and the pore structure was regular with complete macro-pore formation and large specific surface area. The NOx conversion was sensitive to temperature but nearly insensitive to NH3 . The catalyst showed strong adaptability to NOx concentration with activity above 80% in the range of 615-1640 mg·m-3 . Within the range of 720-8640 h continuous operation, the NOx conversion dropped at a rate of about 1% reduction per 600 h.     

Dehydrogenation of i-butane on CrOx/Al2O3 catalysts prepared by ALE and impregnation techniques

Atomic layer epitaxy (ALE), a technique relying on saturating gas–solid reactions, was applied in the preparation of CrO_x/Al₂O₃ catalysts using Cr(acac)₃ vapor and air as source materials for CrO_x. Vaporized Cr(acac)₃ was reacted with preheated Al₂O₃, and the surface complex formed was treated with air to remove the ligand residues. The Cr loading increased from 1.3 to 12.5 wt.% as the number of saturating Cr(acac)₃ and air reactions was increased from one to 10. CrO_x/Al₂O₃ catalysts were also prepared from solution by incipient wetness impregnation (0.3–21 wt.%). XPS and UV–VIS measurements of the catalysts revealed the presence of both Cr⁶⁺ and Cr³⁺. Although the oxidation state distribution was similar, H₂-temperature programmed reduction (TPR) and solubility measurements indicated that Cr⁶⁺ surface sites were in stronger interaction with Al₂O₃ and more uniformly distributed in the catalysts prepared by ALE than by impregnation. On the basis of the activity of the catalysts in the dehydrogenation of i-butane, we propose that the dehydrogenation reaction uses both reduced Cr⁶⁺, i.e. redox Cr³⁺, and exposed non-redox Cr³⁺ sites. Furthermore, the dehydrogenation reaction must be insensitive to the size of the CrO_x ensembles since activities were similar for the catalysts prepared by ALE and impregnation. The decay of the dehydrogenation activity in successive prereduction–reaction–regeneration cycles was attributed to a decrease in the number of redox Cr³⁺ sites.     

Internal Oxidation of Ce3+-BaTiO3 Solid Solutions

The reoxidation process in highly Ce³⁺-doped BaTiO₃ ceramics was studied using TEM. Samples of two different types of solid solutions, Ba_1−XCe³⁺ _X Ti_1−X/4( V _Ti) X/4 O₃ and Ba_1−XCe³⁺ _X Ti⁴⁺_{1− X} Ti³⁺ _X O₃, were prepared by sintering oxide mixtures in air and in a reducing atmosphere, respectively. The solid solutions were reoxidized by annealing in air at high temperatures (1000°—1100°C). As a result of internal oxidation of Ce³⁺ and Ti³⁺, fluorite CeO₂ and monoclinic Ba₆Ti₁₇O₄₀ phases were precipitated in the perovskite matrix. In Ba_1−XCe³⁺ _X Ti_1−X/4( V _Ti)X/4O3 solid solution precipitates nucleate heterogeneously at grain boundaries and at extended defects inside the grains, whereas in Ba_1−XCe³⁺_XTi⁴⁺_1−XTi³⁺_XO₃ solid solution precipitates are nucleated mainly homogeneously inside reoxidized perovskite grains. The form of the precipitates and their orientational relationship with the matrix, as well as the mechanism of internal oxidation, are discussed.     

SnWO4/g-C3N4复合光催化剂降解亚甲基蓝溶液

采用溶剂热法制备SnWO_4/g-C_3N_4复合光催化剂,在可见光降解亚甲基蓝实验中研究复合催化剂的光催化性能。考察催化剂投加量、亚甲基蓝溶液初始浓度、溶液pH值、盐效应对光催化性能的影响及SnWO_4/g-C_3N_4复合光催化剂的重复利用性。实验结果表明,在催化剂投加量1.0 g·L~(-1)、亚甲基蓝溶液初始浓度15 mg·L~(-1)和溶液pH值7.08时,在可见光条件下反应3 h,亚甲基蓝溶液脱色率达到94.2%;NaCl对光催化降解亚甲基蓝具有抑制作用,加入10 mmol·L~(-1)的NaCl溶液后亚甲基蓝的脱色率降为76.0%;复合光催化剂循环使用5次后,暗吸附后光照3 h,亚甲基蓝溶液的总脱色率仍可达到78.7%,重复利用性良好。     

Phase Diagram of the System BaO-Fe2O3

The phase diagram of the system BaO-Fe₂0₃ was determined by X-ray diffraction, melting-point measurement, and microscopic methods. Since the reduction of Fe³⁺ to Fe²⁺ was observed by chemical analysis in the samples heated at high temperature, especially in molten samples, the samples were heated at 1 atmosphere pressure of oxygen in the temperature region in which the liquid was in equilibrium; 1 atmosphere pressure of oxygen was su5cient to restrain the reduction of Fe³⁺. In the temperature region of solid-solid equilibrium, the dissociation was not observed even when the samples were heated in air. BaO - 6Fe₂O₃ formed a solid solution with BaO.Fe₂0₃. The BaO:Fe₂0₃ ratio of the solid solution was BaO.4.5Fe₂0₃ at 1350°C. and BaO. 5.0Fe₂0_a at 800°C. The precipitation micro-structures of each primary solid solution were observed.     

Fe/Al_2O_3催化剂催化氧化兰炭废水

采用浸渍法制备Fe/Al_2O_3催化剂,采用BET、XRD和穆斯堡尔谱等进行结构和性能表征。以自制Fe/Al_2O_3为催化剂,应用催化湿式过氧化氢氧化技术处理COD为6 742 mg·L-1的兰炭废水,通过建立正交实验确定最佳实验条件,结果表明,在p H=4、过氧化氢添加量9.6 m L、反应时间150 min和反应温度80℃条件下,兰炭废水COD去除率达66.30%。对催化氧化后的废水进行GC-MS分析,确定最终氧化产物主要为乙酸。表明自制Fe/Al_2O_3催化剂具有优良的催化效果,并使大分子难降解有机污染物分解为易生化的小分子污染物,甚至被完全分解矿化。     

Thermal Expansion of Homogeneous and Gradient Solid Solutions in the System KZr2(PO4)3─KTi2(PO4)3

Low-thermal-expansion ceramics having arbitrary thermal expansion coefficients were synthesized from homogeneous solid solutions in the system KZr₂(PO₄)₃─KTi₂(PO₄)₃ (KZP–KTP). Dense and strong ceramics were fabricated by sintering at 1100° to 1200°C with 2 wt% MgO. The thermal expansion coefficient increased from 0 to +3 × 10⁻⁶/°C with increasing x in KZr_{2 − x}Ti_x (PO₄)₃ (KZTP). In addition, a functionally gradient material with respect to thermal expansion was prepared by forming a series of KZTP solid solutions in a single ceramic body. By heating a pile of KZP and KTP ceramics in contact with each other, KZP and KTP bonded together to form a KZTP gradient solid solution near the interface.