烧结反应对液相法制得FeWO_4微米晶光催化性能的改性（英文）

通过简单的液相法制得FeWO_4微米晶,FeWO_4微米晶于310℃、空气气氛条件下烧结,研究了烧结反应对FeWO_4微米晶光催化性质的影响。烧结前后的样品通过X射线粉末衍射、扫描电子显微镜、透射电子显微镜、N2吸附-脱附、热重分析、红外分析和紫外-可见等分析方法加以表征。光催化实验证明烧结后其在降解罗丹明B溶液中表现出了较高活性,说明烧结反应有利于提高FeWO_4的吸附与光催化性能。     

g-C3N4纳米管的制备及其光催化降解性能

以三聚氰胺和碳酸氢铵混合物为原料,采用简便热解法制备g-C₃N₄纳米管。热解过程中碳酸氢铵分解释放出大量的NH₃,能够诱导纳米管的形成。利用X射线衍射（XRD）、扫描电子显微镜（SEM）、红外光谱（IR）、N₂吸附-脱附、紫外-可见漫反射光谱以及紫外可见光谱（UV）等分析测试方法对该光催化剂的微观形貌结构和催化性能进行了表征。以罗丹明光催化降解为模型反应研究了g-C₃N₄纳米管的光催化活性。g-C₃N₄纳米管的表面积明显增大,且能够有效地促进光生电子转移,在可见光下具有较强的光催化性能,降解率在60和120 min时分别能达到95%和99.4%,且循环重复利用5次后降解率不低于92%。     

Fe3O4/MAl水滑石(M=Zn、Co、Ni)复合物光催化降解亚甲基蓝的性能、动力学与机理

基于低成本、无毒害、光吸收性强的四氧化三铁（Fe₃O₄）和大比表面、高稳定性的水滑石（LDHs）,制备了Fe₃O₄@MAl-LDHs （M=Zn、Co、Ni）复合物并用于典型偶氮染料亚甲基蓝的光催化降解。通过X射线粉末衍射（XRD）、紫外可见（UV-Vis）吸收光谱、扫描电子显微镜（SEM）、透射电子显微镜（TEM）以及N₂吸附-脱附测试表征了复合材料的组成与结构。光催化实验表明,最佳反应条件为催化剂用量50 mg、光照强度500 W、pH=9、反应温度40℃,此时,Fe₃O₄@MAl-LDHs复合材料对亚甲基蓝的降解率从LDHs的23.2%大幅提升到87.0%。LDHs对亚甲基蓝的降解主要来自·OH,而Fe₃O₄@CoAl-LDHs光降解活性的贡献主要由·OH和空穴提供。此外,LDHs和Fe₃O₄@CoAl-LDHs的电化学性质也存在较大差异。     

自组装α-Fe2O3亚微米球的制备及其光催化性质

在乙二醇体系中, 通过简单的二步方法成功合成了α-Fe₂O₃亚微米球。第一步,以Fe(NO)₃和C₆H₁₂N₄为主要反应物160 ℃溶剂热反应8h制备出前驱体;第二步,煅烧前驱体成功合成了斜方相的α-Fe₂O₃产物。利用X射线粉末衍射(XRD),扫描电子显微镜(SEM),透射电子显微镜(TEM),红外吸收光谱(FTIR),能谱分析(EDS)和热重分析(TGA)等手段对产物进行了表征。在300 W紫外灯(主波长为365 nm)照射下降解一定浓度的甲基橙溶液,研究不同光催化剂对甲基橙溶液降解效果。由于制备产物的形貌和粒径影响其比表面积和对反应物的吸附能力以及带隙能,使得制备产物具有良好的光催化性能。结果表明,α-Fe₂O₃亚微米球在紫外光照射条件下对甲基橙溶液有光降解作用。     

多孔超薄g-C3N4纳米片负载Pt复合材料的制备及其光催化性能

以三聚氰胺为前驱体,通过热氧化刻蚀法制备多孔超薄g-C₃N₄纳米片（CNHS）,将其与氯铂酸钾溶液混合后采用原位光化学还原法成功制备了CNHS负载Pt光催化剂（Pt-CNHS）。使用粉末X射线衍射、场发射扫描电子显微镜、X射线光电子能谱、透射电子显微镜、紫外可见漫反射光谱和N₂吸附-脱附测试等技术对所制备样品的结构、形貌、光吸收特性、光电化学性能和比表面积等进行系统分析。并以气相甲苯为目标降解物,研究其光催化性能。结果表明,相对于体相g-C₃N₄（CNB）和CNHS,Pt的引入可以有效增强催化剂对可见光的吸收能力、响应范围及载流子分离效率。与纯g-C₃N₄和CNHS相比,Pt-CNHS在紫外和可见光照射下均表现出更高的光催化降解气相甲苯的活性。此外,也对Pt-CNHS光催化剂在可见光照射下降解气相甲苯的反应历程做了初步研究。     

Ag2S/Ag3PO4/Ni复合薄膜的制备及其光催化性能

采用电化学方法制备Ag₂S/Ag₃PO₄/Ni复合薄膜,以扫描电子显微镜（SEM）、X射线衍射（XRD）、紫外-可见漫反射光谱（UV-Vis DRS）对薄膜的表面形貌、晶相结构、光谱特性及能带结构进行了表征,以罗丹明B为模拟污染物对薄膜的光催化活性和稳定性进行了测定,采用向溶液中加入活性物种捕获剂的方法对薄膜的光催化机理进行了探索。结果表明：最佳工艺制备的Ag₂S/Ag₃PO₄/Ni是由均匀的球形纳米颗粒构成的薄膜,其光催化活性明显优于纯Ag₃PO₄/Ni薄膜和纯Ag₂S/Ni薄膜,且在保持薄膜光催化活性基本不变的前提下可循环使用6次。提出了可见光下Ag₂S/Ag₃PO₄/Ni复合薄膜光催化降解罗丹明B的反应机理。     

亚稳态MInS2(M=Ag，Cu)花状微米球的热分解法合成及其生长机理

采用热分解法制备了三维的亚稳态正交相AgInS₂和六方相CuInS₂花状微米球。通过X射线衍射（XRD）,场发射扫描电子显微镜（FESEM）等对样品进行表征,对AgInS₂的光催化性能进行了评估,并借助于热重分析（TG-DTA）等手段研究了亚稳态正交相AgInS₂和六方相CuInS₂花状微米球的生长机理。实验结果表明,反应温度和反应物中金属离子的投料比对生成纯相的MInS₂均有影响,而AgInS₂花状微米球能在可见光下较好地催化降解亚甲基蓝。     

火焰辅助热解方法制备Ag2O/TiO2及其光催化制氢性能

以钛酸丁酯和硝酸银为前驱体,采用一步火焰辅助热解法制备了Ag₂O/TiO₂光催化剂并研究了样品在紫外-可见光照射下的光催化制氢性能。利用X射线衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、X射线光电子能谱（XPS）和紫外-可见漫反射吸收光谱（UV-Vis DRS）对样品进行了表征。XRD结果表明TiO₂均为锐钛矿晶型,Ag的引入对XRD结果无明显影响。SEM图显示未修饰的TiO₂是微球形貌,随着引入Ag含量的增加,微球减少直至消失。通过XPS分析和化学沉淀法表明样品中Ag的存在形式为Ag₂O。UV-Vis DRS测试发现引入Ag后提高了样品的光吸收。前驱体中Ag的量影响样品的光催化活性,最高的光催化制氢的活性可以达到相同条件下的P25的15倍。对光催化反应后的样品进行分析,认为在光催化过程中部分Ag₂O通过光生电子转化为Ag形成Ag/TiO₂,进一步提高光催化制氢活性。     

可见光响应催化剂BiVO4六角形微米棒的水热合成

以Bi(NO₃)₃·5H₂O和NH₄VO₃为原料并以聚乙烯吡咯烷酮(PVP)为模板剂通过水热法制备了BiVO₄六角形微米棒晶体。采用XRD、SEM、IR、Raman、UV-Vis、光催化等对产品进行了表征和分析。结果表明,PVP辅助水热法能够合成直径125~300 nm、长度在1.0~1.6 μm内的形貌均一且结晶度高的单斜白钨矿BiVO₄六角形微米棒晶体。相比BiVO₄颗粒,该棒状样品的紫外-可见光吸收边发生了稍许红移,其能带隙减小至2.25 eV。光催化结果表明,添加2.0 g PVP时的BiVO₄微米棒对亚甲基蓝具有最强的可见光催化降解活性,其光照射浓度为10 mg·L^-1亚甲基蓝溶液2 h时的降解率达到99%。     

MOF-808/Bi2MoO6复合材料的构筑及其光催化性能

采用简单的两步水热法制备出了锆基金属有机骨架和钼酸铋的复合材料MOF-808/Bi₂MoO₆。通过X射线粉末衍射、傅里叶红外光谱、扫描电子显微镜、透射电子显微镜、X射线光电子能谱、紫外可见漫反射光谱、N₂吸附-脱附测试和电化学测试对所制备材料的组成、微观结构、光学性质以及光生载流子的复合效率进行了分析。与纯Bi₂MoO₆和MOF-808相比,0.5%-MOF-808/Bi₂MoO₆复合材料展示出了较高的光催化活性,在可见光照射120 min时对抗生素环丙沙星(CIP)的降解率达89.7%。通过自由基捕获实验,证明了·O₂^-是主要活性物种,基于此我们提出了可能的光催化降解机理。     

Near infrared study of aqueous rare-earth ethylsulfates

The near infrared spectra of aqueous solutions of the ethylsulfates of La, Nd, Gd, Tb, Er, Yb, Lu, Y, and Na have been determined from about 0.2 mol-dm^–3 to nearly saturation. The extinction coefficients of water have been calculated taking into account the absorption of ethylslfate anions determined in separate experiments. Their values appeared to be nearly the same as that of pure water. The relative contents of free OH groups in 0.5 and 0.7M solutions have been estimated from the absorbances at 1160 nm. They were lower in solutions of the heavy rare-earth ethylsulfates (Tb, Er, Yb, Lu) than in equimolar solutions of the lighter ones (La, Nd), confirming our previous view that secondary hydration of the heavy trivalent rare-earth cations is distinctly stronger than that of the lighter ones. A comparison of the spectra of these aqueous ethylsulfates with those of perchlorates shows that the structure-breaking ability of the C₂H₅SO ₄ ^– ion is much smaller than that of perchlorate anion.     

Microstructures of Some Bi-W-Nb-O Phases

Microstructures of three Bi-W-Nb-O phases have been examined by using high-resolution transmission electron microscopy. Bi₁₇W₂Nb₃O₃₉ and Bi₁₇WNb₃O₃₆ have incommensurate superstructures derived from the defect fluorite-type δ-Bi₂O₃ and can be regarded as intermediate phases between the type II solid solutions in the Bi-Nb-O and Bi-W-O systems. Bi₈W₂Nb₂O₂₃ has a Bi₂WO₆-like subunit cell with a stepped superstructure. Formation mechanisms of various superstructures are discussed.     

Reactivity of Binary Mixtures of La(III) Oxide and Cu(II) Oxalate or Nitrate and Synthesis of La(III) Cuprate

Reactivity of mixtures of La(III) oxide and Cu(II) oxalate/nitrate in hydrated as well as anhydrous state was studied using TG, DTA and XRD. Cu(II) oxide formed in the endothermic decomposition of mixture containing hydrated Cu(II) nitrate and La(III) oxide could not form La₂CuO₄ while Cu(II) oxide formed in the exothermic decomposition of mixture containing hydrated/anhydrous Cu(II) oxalate and La(III) oxide reacts with La(III) oxide and develops the phases CuLaO₃ and La₂CuO₄. The maximum reactivity with respect to the formation of La₂CuO₄phase was observed in mixture containing anhydrous Cu(II) oxalate. This revised version was published online in July 2006 with corrections to the Cover Date.     

电感耦合等离子体光谱法测定铜冶炼烟尘中锌

本实验介绍了电感耦合等离子体光谱法测定铜冶炼烟尘中锌含量的分析方法。针对样品碳,硅含量高的特点,有针对性的研究了样品的消解方法,确定采用盐酸、硝酸、氢氟酸、高氯酸对铜冶炼烟尘样品进行消解。同时进行了干扰试验,确定样品中高含量的铜,铅,砷等对样品测定结果没有影响。并对仪器的工作参数进行了优化。方法检出限为为0.011 mg/L,测定下限为0.019 mg/L,3个样品的相对标准偏差在0.54%~0.92%之间,加标回收率在96%~101.14%之间。该方法样品消解完全,流程短,操作简单,快速,测定准确度高,可以满足铜冶炼烟尘中锌含量的测定。     

Synthesis and characterization of gallium-based perovskitetype dense membrane with oxygen semipermeability

La0.15Sr0.85Ga0.3Fe0.7O3-δ(LSGFO) and La0.15Sr0.85Co0.3Fe0.7O3-δ(LSCFO) mixed oxygen-ion and electron conducting oxides were synthesized by using a combined EDTA and citrate complexing method, and the corresponding dense membranes were fabricated. The properties of the oxide powders and membranes were characterized with combined SEM, XRD, H2-TPR, O2-TPD techniques, mechanical strength and oxygen permeation measurement. The results showed that LSGFO had much higher thermochemical stability than LSCFO due to the higher valence stability of Ga3+. After the temperature-programmed reduction by 5% H2 in Ar from 20℃to 1020℃, the basic perovskite structure of LSGFO was successfully preserved. LSGFO also favors the oxygen vacancy formation better than LSCFO. Oxygen permeation measurement demonstrated that LSGFO had higher oxygen permeation flux than LSCFO, but they had similar activation energy for oxygen transportation, with a value of 110 and 117 kJ ?mol~(-1), respectively. The difference in oxygen permeation f     

Preparation of ZrO2-TiO2-CeO2 and Its Application in the Selective Catalytic Reduction of NO with NH3

TiO₂,ZrO₂-TiO₂,andZrO₂-TiO₂-CeO₂ were prepared by co-precipitation method and characterized by X-ray diffraction (XRD), specific surface area measurements (BET), temperature programmed desorption (NH₃-TPD), oxygen storage capacity (OSC), and temperature programmed reduction (H₂-TPR). The results showed that ZrO₂-TiO₂-CeO₂ exhibited large number of surface strong acid, possessed some oxygen storage capacity, and strong redox property. The three materials were used as supports and the monolith catalysts were prepared with 1% (w) V₂O₅ and 9% (w)WO₃ for selective catalytic reduction (SCR) of NO with ammonia in the presence of excessive O₂, and the results of catalytic activity showed that the catalyst used ZrO₂-TiO₂-CeO₂ as support yielded nearly 100% NO conversion at 275 °C at a gas hourly space velocity (GHSV) of 10000 h⁻¹, and it had the best catalytic activity and showed great potential for practical application.     

Titania-supported mixed HPMoV polyoxometallates as precursors of hydrodesulfurization catalysts

HDS catalysts were prepared by loading H₃PMo₁₂O₄₀ or H₄PMo₁₁V₁O₄₀ polyoxometallates on TiO₂ (0.5 and 1.0 mmol (Mo+V)). Activity of the catalysts was tested in the HDS of thiophene. The activity of catalysts of low concentration was 2–3 times higher than the activity of those of high concentration. Temperature programmed reduction (TPR) and IR spectroscopy were used to determine the properties of the catalyst. TPR measurements proved that vanadium promotes and stabilizes HDS activity due to an increase in the Mo⁵⁺/Mo⁴⁺ ratio.     

α-Fe2O3掺杂对In2O3电导和气敏性能的影响

用化学共沉淀法制备了α Fe2O3掺杂的In2O3纳米晶微粉,研究了α Fe2O3掺杂对In2O3电导和气敏性能的影响. 结果表明, α Fe2O3和In2O3间可形成有限固溶体In2－xFexO3(0≤x≤0.40); Fe3＋对In2O3晶格中In3＋格位的部分取代,大大增强了阴阳离子间的结合力,导致材料中氧空位VO×数骤降、 自由电子的浓度变稀和电导下降. n(Fe3＋):n(In3＋)=5 :5的共沉淀粉于800 ℃下灼烧4 h所得的α Fe2O3掺杂In2O3传感器元件,对45 μmol•L－1 C2H5OH的灵敏度达54.0,为相同浓度干扰气体汽油的8倍多.     

B2O3-Bi2O3-ZnO-Al2O3玻璃助烧剂对BaTiO3陶瓷烧结条件、晶体结构和介电性能的影响

通过调节B₂O₃-Bi₂O₃-ZnO-Al₂O₃(BBZA)玻璃的添加量研究其对钛酸钡(BaTiO₃)陶瓷烧结条件、晶体结构和介电性能的影响。结果表明：添加适量的BBZA玻璃能够有效地将BaTiO₃陶瓷烧结温度由1 350℃降至950℃,并使其致密化。同时,添加BBZA玻璃后,BaTiO₃的晶体结构随着烧结温度的升高而发生转变(立方相→四方相)。另外,BBZA玻璃的引入使BaTiO₃陶瓷的居里峰得到了有效的抑制和拓宽。陶瓷微观形貌显示,玻璃相均匀分布在BaTiO₃晶粒表面。优化的BaTiO₃陶瓷制备条件如下：BBZA添加量(质量分数)为2.0%,烧结温度为950℃。在该条件下制备的BaTiO₃陶瓷介电常数达到1 364,介电损耗低至1.2%。     

B2O3-Bi2O3-ZnO-Al2O3玻璃助烧剂对BaTiO3陶瓷烧结条件、晶体结构和介电性能的影响

通过调节B₂O₃‐Bi₂O₃‐ZnO‐Al₂O₃(BBZA)玻璃的添加量研究其对钛酸钡(BaTiO₃)陶瓷烧结条件、晶体结构和介电性能的影响。结果表明：添加适量的BBZA玻璃能够有效地将BaTiO₃陶瓷烧结温度由1350℃降至950℃,并使其致密化。同时,添加BBZA玻璃后,BaTiO₃的晶体结构随着烧结温度的升高而发生转变(立方相→四方相)。另外,BBZA玻璃的引入使BaTiO₃陶瓷的居里峰得到了有效的抑制和拓宽。陶瓷微观形貌显示,玻璃相均匀分布在BaTiO₃晶粒表面。优化的BaTiO₃陶瓷制备条件如下：BBZA添加量(质量分数)为2.0%,烧结温度为950℃。在该条件下制备的BaTiO₃陶瓷介电常数达到1364,介电损耗低至1.2%。