CexPr1-xO2-δ复合氧化物的XRD和Raman表征

A series of Ce_xPr_1-xO_2-δ mixed oxides were synthesized by sol-gel method and characterized by Raman and XRD techniques. When x value was changed from 1.0 to 0.5, only a cubic phase CeO₂ was observed. The samples were very well crystallized on decreasing x from 0.50 to 0.99. For Ce_xPr_1-xO_2-δ samples 465 cm^-1 and 1 150 cm^-1 Raman peaks are attributed to the Raman active F_2g mode of CeO₂. The broad peak at about 570 cm^-1 in the region of 0.3 ≤x≤ 0.99 can be linked to lattice defects resulting in oxygen vacancies. The new band at about 195 cm^-1 may be attributed to the asymmetric vibration caused by the formation of oxygen vacancies. Calcination temperatures had great effect on the peak intensity for CeO₂ but less effect on Ce_0.8Pr_0.2O_2-δ in Raman spectra. It might be due to the transformation of the colors for the mixed oxides, the insertion of Pr atom into the ceria lattice could enhance the sintering resistance and thermal stability of the mixed oxides.     

Cu1-xAgxI(x=0.5～0.6)纳米微粒的制备与表征

In the presence of PVPK30,Cu_1-xAg_xI nanoparticles were prepared by ion exchange reaction.The product was characterized by FT-IR,XRD,TEM,EDS and SPS,respectively.It was found that the value of x is ap-proximately 0.5～0.6and the average diameter of the nanoparticles is 10～20nm.The product shows surface photovoltage property of semiconductor and the existence of Cu⁺ greatly enhances the separation efficiency of photoinduced electron-hole pairs.Meanwhile,SPS of Cu_1-xAg_xI nanoparticles with different X (Ag/I)value had been investigated. The results show that when X is 0.5～0.576, the SPS intensity of Cu_1-xAg_xI nanoparticles is highest.     

掺镍型层状LixNiyMn1-yO2正极材料的合成与电性能研究

A kind of cathode material of layered Li_xNi_yMn_1-yO₂ characterized with the O2 type has been synthesized by a simple method. Its precursor Na_xNi_yMn_1-yO₂ has been prepared from manganese dioxide， nickel hydroxide and sodium carbonate at high temperature in air and quickly cooled in cold water， then it has been exchanged by the melted LiNO₃ at 300～400℃ in air. The effects of calcine-temperature for the precursors and its compositions (the content of Na and Ni) on the electrochemical properties of the material Li_xNi_yMn_1-yO₂ have been investingated by XRD and electrochemical tests. The results show that the sample Li_0.7Ni_0.3Mn_0.7O₂， has the best electrochemical properties which shows only one charge-discharge potential stage of 2.8～3.0V and has a high specific capacity over 180mAh·g^-1 cycled between 2.0～4.20V. A significant structure transformation to the spinal-type phase has not been found in the charge-discharge cycling and the discharge specific capacity around 165mAh·g^-1 has re-mained after the 20th cyclings for the material.     

纳米Mn-Zn铁氧体的制备和研究

Nanosize manganese zinc ferrites were fabricated by hydrothermal precipitation route using Fe₂(SO₄)₃, ZnSO₄·7H₂O, MnSO₄·H₂O as material, then some calcinated at 500 ℃ and studied by XRD, TEM, IR and VSM. The results showed that the products were spinel crystal structure and uniformly sized nanoparticles (15～25 nm) with little aggregation. The analysis of IR showed that the superficial water can be eliminated, but that was embedded in crystal lattice can not be removed by calcinating. The effect Zn content x on the lattice (a) of nanosize Mn_1-xZn_xFe₂O₄ was also discussed. The lattice of nanosize Mn_1-xZn_xFe₂O₄ decreases with x increasing; and its value deviated the standard lattice (a₀) of normal size manganese zinc ferrites. A lot of water was absorbed during the hydrothermal process owing to the large surface of nanosize particles. The change of magnetic properties of Mn_xZn_1-xFe₂O₄ with x increasing was studied: nanosize Mn_xZn_1-xFe₂O₄ particles synthesized by us exhibited peculiar magnetic properties curve with Zn content (x) increasing, Superparamagnetic behaviors of the synthesized ZnFe₂O₄ samples were confirmed by magnetic characterization, which can be explained by the difference between the distribution of the metal ions (Mn²⁺, Zn²⁺ and Fe³⁺) among the tetrahedral (A) and the octahedral (B) sites of nanosize ferrite and that of bulk ferrite.     

CrOx/ SBA-15介孔催化剂上丙烷在二氧化碳气氛中脱氢反应的研究

The structure and catalytic properties based on Chromium Oxide supported on mesoporous SBA-15 for oxidative dehydrogenation of propane by CO₂ have been studied by using X-ray diffraction (XRD), ultraviolet-visible diffuse reflectance spectra (UV-Vis DRS), electron spin resonance (ESR), X-ray photoelectron spectroscopy (XPS) and propane pulsing experiments in the absence of gas-phase O₂. It has been shown that propane conversion and propene yield increase with Cr loadings. The propane conversion and propene yield on CrO_x(Cr: 10wt%)/SBA-15 catalyst for oxidative dehydrogenation of propane by CO₂ at 550 ℃ reach 24.8% and 21.8%, respectively .The results of ESR, UV-Vis DRS and propane pulsing experiments indicate that Cr^Ⅲ in the CrO_x/ SBA-15 catalyst is the main active species in oxidative dehydrogenation of propane by CO₂ and Cr^Ⅵ, Cr^Ⅴ is inactive in dehydrogenation.     

纳米Ce1-xLaxO2-δ的微波引诱燃烧合成及其性能表征

Nanometer Ce_1-xLa_xO_2-δ solid solutions were synthesized by microwave-induced combustion process us-ing cerium nitrate hexahydrate， lanthanum nitrate hexahydrate and urea as raw materials. The process took only six minutes to obtain La₂O₃-doped CeO₂ nanopowders. The nanopowders were characterized by XRD， Laser Raman spectrum ， UV-Vis spectroscopy，field-emission scanning electron micrograph(FE-SEM)and TEM. The results revealed that the grain size of Ce_1-xLa_xO_2-δ varied from 20 to 40 nm calculated by Scherer formula through the plane of (111)， that oxygen vacancy was produced in the crystal lattices and the concentration of oxygen vacancy was increased with La doping， therefore the covalence of Ce-O bond was strenthened， which results in more intensive UV-C(200～280 nm)absorption. It can be seen from SEM that the porous appearance was obtained. Grain size is no more than 40nm observed from TEM.     

纳米钙钛矿LaxSr1-xFe1-yCoyO3复合氧化物的制备和表征

用甘氨酸-硝酸盐燃烧合成法，制备La_xSr_1-xFe_1-yCo_yO₃复合氧化物的陶瓷粉末，对该钙钛矿型氧化物进行了XRD、IR、紫外漫反射光谱及循环伏安曲线分析。结果表明：该复合氧化物粉体平均晶粒为15.3～29.8 nm,为立方和正交晶系。该氧电极具有双功能催化特性，但不完全可逆。对水溶液染料进行光解实验，利用紫外-可见、人工神经网络光度法研究La_xSr_1-xFe_1-yCo_yO₃的催化性能。结果表明：CO²⁺的加入可使La_xSr_1-xFeO₃的光催化活性有所提高，B位离子(Fe³⁺，CO²⁺)改变与加入，使La_xSr_1-xFe_1-yCo_yO₃(x=0.7，0.3；y=0.3，0.9，1)光催化活性高于La_xSr_1-xFeO₃。同时，对5种染料进行紫外光解，在0.75 h，脱色率大于91%，并为动力学一级反应。     

LixNi0.8-yCo0.2ZnyOp的合成及电化学性能研究

A series of single-phase Li_xNi_0.8-yCo_0.2Zn_yO_p(0.96 ≤x≤ 1.10， 0 ≤y≤ 0.05， 2 ≤p≤ 2(1+y) ) (different in the y values) were synthesized by a two-step solid state reaction method， in which LiOH·H₂O， Zn-doped spherical Ni(OH)₂ and Co₂O₃ were used as the precursors. The ICP-AES analyses proved that the Zn-doped compounds synthesized had the nonstoichiometric form. The results of the XRD， SEM identified that the uniform particles of the as-prepared materials having a good layered structure were fine， narrowly distributed and well crystallized. The electrochemical performance test was carried out and the results showed that the as-prepared Zn-doped materials had not only a high capacity， but also a better cycling stability characterization than the un-doped one. The Li_1.06Ni_0.75Co_0.22Zn_0.03O_2.03 material has an initial reversible capacity as high as 160.5mAh·g^-1; and a first discharge efficiency 89.2%， and exhibits satisfactory cyclic stability with 90% retainable capacity after 50 cycles.     

纳米尖晶石LixMn2O4的制备与电化学性能表征

Nano-spinel Li_xMn₂O₄(0.6 ≤x≤ 1.0) was synthesized by two steps of coprecipitation and calcination. The influences of calcination temperature, time and Li/Mn ratio on the crystal structure and the particle size of Li_xMn₂O₄ were investigated. It was shown that the higher the calcination temperature, the more complete the crystal structure, and the larger the particle size. Moreover, the influence of calcination time on the crystal structure was insignificant when it was more than 3h at 700℃. With the increase of x in Li_xMn₂O₄ in the range of 0.6～1.0, the d111 and lattice parameter a increased first and then decreased. The electrochemical properties of nano-spinel LiMn₂O₄ using as cathode material of lithium-ion battery were studied. The low discharge capacity might be due to the irreversible capacity loss brought by the large surface area and lattice vacancies of the nano-spinel.     

Eu3+离子在Ca2PbO4一维结构基质中的发光研究

A Eu³⁺-doped Ca₂PbO₄ with one-dimensional structure was prepared with a solid-state reaction method and its characteristics were investigated. The XRD results show that the substitution of Ca²⁺ by Eu³⁺ has no influence on the structure of Ca₂PbO₄. Under the excitation of ultraviolet light， the Ca₂PbO₄:Eu³⁺ phosphor exhibits strong red emission at about 618 nm which is assigned to the ⁵D₀- ⁷F₂ electric-dipole transition. The compounds Sr₂CeO₄ and Ca₂SnO₄ have the same crystal symmetry as that of Ca₂PbO₄ and it is found that the emission intensity of Ca₂PbO₄∶Eu³⁺ is higher than that of Sr₂CeO₄∶Eu³⁺ and lower than that of Ca₂SnO₄∶Eu³⁺. The excitation spectrum of Ca₂PbO₄∶Eu³⁺ appears to be a broad band with two peaks at about 289 nm and 340 nm. The former peak is attributed to the Eu³⁺-O₂- charge transfer transition， while the latter one may be related to the absorption of Ca₂PbO₄ host or its crystal defects.     

直接Z型Zn2SnO4-xNx/ZnO1-yNy异质结光催化剂的制备及机理

采用微波溶剂热法成功制备直接Z型Zn_2SnO_(4-x)N_x/ZnO_(1-y)N_y核壳结构异质结光催化剂。2种物质不同的功函数改变了其表面电荷密度,并在界面处形成内建电场,导致其从传统的Ⅰ型镶嵌异质结转变为Ⅱ型异质结,再转变为Z型异质结构。N杂质原子替代O原子进入Zn_2SnO_4和ZnO的晶格,在两者的价带(VB)顶部形成双杂质能级。核壳结构的Z型异质结光催化剂对罗丹明B的降解速率为纯相Zn_2SnO_(4-x)N_x的1.40～1.43倍,同时具有良好的循环稳定性,且可以降解亚甲基蓝、甲基橙、水杨酸等污染物。Z型异质结的形成使其光生电子-空穴对具有较强的氧化还原能力,而双杂质能级的存在可以拓宽其光响应范围并提高载流子的分离效率。因此,Zn_2SnO_(4-x)N_x/ZnO_(1-y)N_y异质结光催化剂高的光催化活性归因于Z型异质结和双杂质能级的协同作用。     

CuxCe1-xO2-x/SBA-15/堇青石整体式催化剂及其CO催化氧化性能

以堇青石蜂窝陶瓷为载体,CuxCe1-xO2-x/SBA-15为催化活性组分,制备了一系列10%~60%Cu0.5Ce0.5O1.5/SBA-15/堇青石和50%CuxCe1-xO2-x/SBA-15/堇青石(x=0~1)整体式催化剂,采用低温氮吸附-脱附、XRD、XPS和H2-TPR对催化剂进行了表征,在微型固定床反应器中评价了催化剂的CO催化氧化活性。结果表明:整体式催化剂仍然保持SBA-15的介孔结构,催化剂中除了堇青石的物相外,还有CuO和CeO2物相,催化剂表面的Cu以Cu2+和Cu+两种状态存在,Ce以Ce4+状态存在,催化剂表面的氧化还原性能与Cu0.5Ce0.5O1.5的含量和Cu、Ce的比例有一定的关系,50%Cu0.5Ce0.5O1.5/SBA-15/堇青石催化剂具有最好催化活性,CO可以在140℃完全转化。     

La2-xBixCuO4阴极材料的合成与电化学性质

采用甘氨酸-硝酸盐法合成了固体氧化物燃料电池阴极材料La_2-xBi_xCuO₄（x=0、0.05、0.10）,并利用X射线衍射（XRD）对材料的物相进行分析。结果表明,La_2-xBi_xCuO₄形成单一的类钙钛矿结构氧化物,且晶胞体积随着铋掺杂量的增加而增大。在950℃烧结24 h过程中,La_2-xBi_xCuO₄不与电解质Sm_0.2Ce_0.8O_1.9（SDC）发生反应,表明这种电解质材料具有良好的高温化学相容性。电导率测试结果表明Bi的掺入显著提高了材料电导率。程序升温脱附测试结果表明,铋的掺杂显著增强了材料的表面氧吸附能力。不同氧分压下的交流阻抗谱测试结果表明,La_1.9Bi_0.1CuO₄阴极在700℃空气中的极化电阻为0.26 Ω·cm²,以电解质SDC支撑的单电池NiO-SDC/SDC/La_1.90Bi_0.10O₄在700℃的最大输出功率密度为308 mW·cm^-2,电极反应的速控步骤为氧分子的扩散与表面吸附过程。     

室温电化学沉积Ba1-xCaxMoO4多晶固溶体薄膜

近年发展起来的制备功能薄膜的电化学沉积技术,是软溶液工艺路线(Soft Solution Processing简记为SSP)中的重要技术[1]。与传统的薄膜制备技术相比,电化学沉积技术在反应控制、形貌控制、沉积速度、能量消耗、环境影响、薄膜晶化以及沉积设备等方面都有较明显的优势,同时避免了     

功能化ZnxCd1-xS纳米晶的制备及其光学性能的研究

以氯化锌、氯化镉和硫化钠为原料，采用巯基乙醇为表面修饰剂，H₂O/DMF为溶剂，制得未团聚且分散均匀的纳米晶溶液，同时得到表面富含羟基基团不同锌镉组成的复合Zn_xCd_1-xS纳米晶。利用FTIR、EDS、UV-Vis、XRD、荧光光谱(PL)考察了复合纳米晶结构和光学性能的关系，并利用紫外灯摄像技术对Zn_xCd_1-xS纳米晶的光致发光性能进行     

NbS_(2-x)Se_x的制备、表征及其摩擦学性能

本文采用固相反应合成了NbS2-xSex纳米材料。并分别采用XRD、SEM、TEM、HRTEM进行了结构、形貌和成分的分析表征。系统研究了合成温度、保温时间及不同掺杂量对产物晶型和形貌演化的影响及规律性。结果表明Se的掺杂使NbS2-x Sex的形貌由纳米带(板)转变为纳米片,衍射峰明显宽化,峰强变弱,晶粒细化。且掺杂量、保温温度及时间对产物的形貌影响较大;在750℃下保温2 h得到的掺杂5at%Se的NbS1.9Se0.1形貌良好。将NbS2-xSex作为液体石蜡油的添加剂的UMT-2摩擦学实验结果表明掺杂后的NbS2-xSex具有优异的摩擦性能,其中掺杂5at%的Se在750℃下保温2 h的NbS1.9Se0.1摩擦性能最佳,同时对其摩擦机理进行了解释。     

NbS2-xSex的制备、表征及其摩擦学性能

本文采用固相反应合成了NbS_2-xSe_x纳米材料。并分别采用XRD、SEM、TEM、HRTEM进行了结构、形貌和成分的分析表征。系统研究了合成温度、保温时间及不同掺杂量对产物晶型和形貌演化的影响及规律性。结果表明Se的掺杂使NbS_2-xSe_x的形貌由纳米带(板)转变为纳米片,衍射峰明显宽化,峰强变弱,晶粒细化。且掺杂量、保温温度及时间对产物的形貌影响较大;在750℃下保温2h得到的掺杂5at%Se的NbS_1.9Se_0.1形貌良好。将NbS_2-xSe_x作为液体石蜡油的添加剂的UMT-2摩擦学实验结果表明掺杂后的NbS_2-xSe_x具有优异的摩擦性能,其中掺杂5at%的Se在750℃下保温2h的NbS_1.9Se_0.1摩擦性能最佳,同时对其摩擦机理进行了解释。     

用于NO_x低温下吸附还原的CoO_x/CeO_2二元氧化物的制备

研究了以多孔二氧化硅微球和活性炭为载体制备NOx吸附/还原催化剂的方法,摸索了最佳Ce/Co物质的量的比例。采用低温氮吸附方法测定了样品的BET比表面和孔容,利用XRD方法表征了样品中所掺杂的金属元素的晶型。研究发现:当nCe/nCo=75/25时,材料获得最佳NOx吸附能力,当以多孔二氧化硅微球作载体时,材料对于NOx的吸附主要来自CoOx和CeO2的二元氧化物;当以活性炭作为载体时,活性炭参与了NOx的吸附,因此其吸附容量大大提高。对NOx的吸附机理进行了探讨,并研究了样品的NH3还原性质。     

CdS插层的K4Nb6-xCuxO17复合物的制备及其光催化制氢活性

以Nb2O5,K2CO3和CuO为原料经高温固相反应合成K4Nb6-xCuxO17催化剂,并通过层间离子交换反应,胺插入反应以及硫化反应制备CdS插层K4Nb6-xCuxO17复合催化剂(K4Nb6-xCuxO17/CdS)。利用X射线衍射(XRD),X射线光电子能谱(XPS),场发射扫描电镜(SEM),X射线能谱仪(EDX),紫外-可见漫反射(UV-Vis),分子荧光光谱(PL)等技术对催化剂进行表征。考察了催化剂的可见光催化制氢活性。结果表明,Cu离子掺杂进入K4Nb6O17晶格中,CdS位于K4Nb6O17层间。CdS插层K4Nb6-xCuxO17催化剂的最大吸收光波长约为550 nm。催化剂制氢活性有明显提高,紫外光和可见光下3 h产氢量分别达到279.83 mmol.gcat-1和7.11 mmol.gcat-1。最后讨论了复合催化剂光生电荷转移机理。