磷化镍修饰磷掺杂氧化镓可见光催化水分解产氢

以Ga₂O₃半导体为前驱体,用浸渍加低温磷化法制备了P掺杂Ga₂O₃表面修饰Ni₂P光催化剂(x-Ni₂P/Ga₂O₃-P_y,x代表Ni²⁺和Ga₂O₃的物质的量之比,y代表NaH₂PO·H₂O与Ga₂O₃的物质的量)。5%-Ni₂P/Ga₂O₃-P₆催化剂展现出在纯水中光催化析氢的高活性,在430 nm光照下的光量子效率为0.22%。机理研究结果表明Ni₂P修饰和P掺杂扩展了催化剂的光响应范围,同时提升了载流子分离迁移效率,其长周期光催化反应稳定性明显优于未磷化催化剂。     

钙钛矿型LaxSr1－xNi1－yCoyO3光电催化活性研究

用甘氨酸-硝酸盐燃烧合成法, 制备La_xSr_1－xNi_1－yCo_yO₃复合氧化物的陶瓷粉末, 对钙钛矿氧化物进行了XRD结构分析. 在通氧或不通氧下测试氧还原和氧析出的循环伏安曲线. 结果表明: 该氧电极具有双功能催化特性, 但不完全可逆. 利用汞灯作为激发光源, 进行几种水溶性染料和五种混合染料光解实验, 利用紫外-可见、红外以及人工神经网络光度法研究La_xSr_1－xNi_1－yCo_yO₃的催化性能. 结果表明: La_xSr_1－xNi_1－yCo_yO₃ (x＝0.7, 0.9, 1; y＝0.3, 0.75)复合氧化物都具有较强光催化特性; La_xSr_1－xNi_1－yCo_yO₃的光催化活性高于La_xSr_1－xNiO₃, 这与B位离子(Ni^2—, Co^2－)的电子构型有关; Co^2＋的加入可使La_xSr_1－xNiO₃的光催化活性有所提高.     

Bi4-xEuxTi3-yMyO12（M=Fe，Co，Ni）纳米颗粒的制备及光学和磁学性能

三层结构的Aurivillius相的Bi_4-xEu_xTi_3-yM_yO₁₂（x=0~0.6;M=Fe/Co/Ni,y=0.01,0.02,0.04,0.06,0.08,0.10）纳米颗粒,是通过共沉淀法和后续的高温煅烧处理所制备的。利用XRD,SEM,PL,Raman,PPMS等方法对样品进行表征,研究了不同掺杂浓度下的产物的物相、形貌和性能等。实验结果表明,通过掺杂,发现纳米颗粒的粒径变小,形貌更均一,分散性也更好。通过对掺杂离子浓度的优化,发现Eu³⁺离子的掺杂浓度为x=0.4时,发光强度是最强的。此外,对Ti位进行了磁性离子（Fe³⁺,Co³⁺和Ni²⁺）的掺杂,实验结果发现随着掺杂的磁性离子浓度的减少,发光强度是逐渐增强,而且产物具有很好的铁磁性。     

纳米Fe3O4及Ni2 掺杂Fe3O4的制备、表征及吸附Pb(Ⅱ)的特性

采用一种改进的共沉淀法制备了纳米磁铁矿(Fe₃O₄)及Ni²⁺掺杂磁铁矿(Ni_xFe_3-xO₄,x=0.1,0.3,0.6),用X-射线衍射(XRD)、扫描电镜(SEM)、氮气物理性吸附、酸碱滴定等手段对产物进行了表征,用平衡吸附法研究了4种样品对Pb(Ⅱ)离子的吸附容量及吸附模型。结果表明,Fe₃O₄和3种Ni_xFe_3-xO₄均为近似球形的单相晶质纳米颗粒;与Fe₃O₄比较,Ni_xFe_3-xO₄的颗粒尺寸变小、表面电荷零点和pH＝5.0时的表面正电荷量降低;样品的孔体积、比表面积和表面分形度以及表面羟基含量都随产物中Ni²⁺掺杂量的增加而升高。4种样品对Pb(Ⅱ)的等温吸附数据均适合用Langmuir模型拟合(R²=0.9942~0.9858),其相关系数的大小表现为：Fe₃O₄>Ni_0.1Fe_2.9O₄>Ni_0.3Fe_2.7O₄=Ni_0.6Fe_2.4O₄;Freundlich模型对样品等温吸附Pb(Ⅱ)的实验数据拟合度较低(R²=0.981 3~0.947 7),4种样品的Freundlich相关系数的大小关系与Langmuir相关系数相反。初始pH=5.0时,Fe₃O₄,Ni_0.1Fe_2.9O₄,Ni_0.3Fe_2.7O₄和Ni_0.6Fe_2.4O₄对Pb(Ⅱ)的最大吸附容量分别为6.02,6.68,7.29和8.34 mg·g^-1。可见,Ni_xFe_3-xO₄(尤其是Ni²⁺掺杂量较高的产物)对水环境中重金属Pb(Ⅱ)的去除能力明显高于Fe₃O₄。     

纳米Fe3O4及Ni2+掺杂Fe3O4的制备、表征及吸附Pb(Ⅱ)的特性

采用一种改进的共沉淀法制备了纳米磁铁矿(Fe₃O₄)及Ni²⁺掺杂磁铁矿(Ni_xFe_3-xO₄,x=0.1,0.3,0.6),用X-射线衍射(XRD)、扫描电镜(SEM)、氮气物理性吸附、酸碱滴定等手段对产物进行了表征,用平衡吸附法研究了4种样品对Pb(Ⅱ)离子的吸附容量及吸附模型。结果表明,Fe₃O₄和3种Ni_xFe_3-xO₄均为近似球形的单相晶质纳米颗粒;与Fe₃O₄比较,Ni_xFe_3-xO₄的颗粒尺寸变小、表面电荷零点和pH＝5.0时的表面正电荷量降低;样品的孔体积、比表面积和表面分形度以及表面羟基含量都随产物中Ni²⁺掺杂量的增加而升高。4种样品对Pb(Ⅱ)的等温吸附数据均适合用Langmuir模型拟合(R₂=0.9942~0.9858),其相关系数的大小表现为:Fe₃O₄>Ni_0.1Fe_2.9O₄>Ni_0.3Fe_2.7O₄=Ni_0.6Fe_2.4O₄;Freundlich模型对样品等温吸附Pb(Ⅱ)的实验数据拟合度较低(R²=0.9813~0.9477),4种样品的Freundlich相关系数的大小关系与Langmuir相关系数相反。初始pH=5.0时,Fe₃O₄,Ni_0.1Fe_2.9O₄,Ni_0.3Fe_2.7O₄和Ni_0.6Fe_2.4O₄对Pb(Ⅱ)的最大吸附容量分别为6.02,6.68,7.29和8.34mg·g^-1。可见,Ni_xFe_3-xO₄(尤其是Ni²⁺掺杂量较高的产物)对水环境中重金属Pb(Ⅱ)的去除能力明显高于Fe₃O₄。     

钴铁双金属氧化物多孔纳米棒的制备及其电解水析氧性能

通过简单的钴铁前躯体热分解法制备了系列一维Co_1-xFe_xO_y（0≤x≤1）多孔纳米材料,并在1 mol·L^-1 KOH溶液中研究了其电解水析氧催化性能。研究发现不同Fe掺杂量对材料的结构与电解水析氧催化性能有较大的影响,其中16%（n/n）Fe掺杂量的Co_1-xFe_xO_y具有最优的析氧催化性能。在10 mA·cm^-2电流密度下其析氧过电位为345 mV,塔菲尔斜率为54 mV·dec^-1,并表现出优异的析氧稳定性能。廉价、高效的Co_1-xFe_xO_y多孔纳米棒材料有望成为优良的析氧催化剂用于电解水制氢。     

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。     

Mg掺杂In2O3-x催化剂光热催化CO2加氢

为提高光热催化CO₂加氢In₂O₃催化剂的催化活性,采用均相水热法制备Mg (OH)₂-In (OH)₃前驱体,通过高温煅烧和H₂-还原处理得到了富含氧空位的Mg掺杂In₂O_3-x(Mg-In₂O_3-x)催化剂。在300℃、常压、可见光照射条件下,CO₂加氢转化为CO的CO₂转化率可达31.20%,CO产生速率为14.22 mmol·g_cat^-1·h^-1,CO选择性为100%。相比于单一In₂O_3-x催化剂,Mg-In₂O_3-x催化剂光热催化CO₂转化率及CO产生速率明显提高,这归因于Mg成功掺杂到In₂O₃晶格中,促进In₂O₃表面氧空位的形成,进而对可见光响应效率大幅提高,并有效减缓光生电子-空穴的复合。     

Development of Cocatalysts for Photocatalytic Overall Water Splitting on (Ga1? x Zn x )(N1? x O x ) Solid Solution

The development of cocatalysts promoting overall water splitting on (Ga_1−x Zn _x )(N_1−x O _x ) solid solution photocatalyst is presented. The (Ga_1−x Zn _x )(N_1−x O _x ) is a stable visible-light-driven photocatalyst for stoichiometric water splitting upon loading with a suitable nanoparticulate cocatalyst. Loading with a combination of Cr and Rh oxides, Rh_2−y Cr _y O₃, is demonstrated to raise the quantum efficiency of (Ga_1−x Zn _x )(N_1−x O _x ) for overall water splitting to 2.5% at 420–440 nm. This represents a 10-fold increase in efficiency over the highest efficiency previously obtained using nanoparticulate RuO₂ as a cocatalyst. In addition to the composition, the dispersion and size of cocatalyst nanoparticles are identified as important factors affecting the degree of enhancement for stoichiometric water splitting. Kazuhiko Maeda—Research Fellow of the Japan Society for the Promotion of Science (JSPS).     

正极材料Li(Ni0.5Mn0.5)1-xMxO2 (M=Ti，Al；x=0，0.02)电化学行为的比较研究

0IntroductionMany efforts have been made to develop newmaterials as an alternative to LiCoO2due to the rela-tively high cost and toxicity of Co.Much attention hasbeen paid to layered structure cathode materials suchas LiMnO2and LiNiO2due to their lower co…     

Studies on electrical properties of system La_(2-x)(Sr_(1-y)Ca_y)_xNiO_4

A new series of solid solutions of composition La_(2-x)(Sr_(2-y)Ca_y)_xNiO_4(0相似文献   

Mechanism of the Formation of Molybdenum Metallocarbene Complexes in the Gas Phase

The reactions of Mo⁺ ions and Mo _x O _y ⁺ oxygen-containing molybdenum cluster ions (x = 1-3; y = 1-9) with methane, ethylene oxide, and cyclopropane were studied using ion cyclotron resonance. The formation of a number of organometallic ions, including the metallocarbene MoCH₂ ⁺ , as well as molybdenum oxometallocarbenes Mo _x O _y CH₂ ⁺ (x = 1-3; y = 2, 4, 5, or 8) and Mo _x O _y (CH₄)⁺ ions (x = 1-3; y = 2, 5, or 8), was detected. The upper and lower limits of bond energies in oxometallocarbene complexes were evaluated: 111 > D ⁰ (Mo _x O _y ⁺-CH₂) > 82 kcal/mol (x = 1-3; y = 2, 5, 8).     

Cr3+在不同基质Y3Ga5O12或Ga2O3中的荧光特性

以Ga_2O_3、Y_2O_3、Cr(NO_3)_3·9H_2O为原料,柠檬酸为配位剂,通过溶胶-凝胶高温固相合成法制备出Ga_(2-2x)O_3∶2xCr~(3+)(Ga_2O_3∶xCr)与Y_3Ga_(5-5x)O_(12)∶5xCr~(3+)(YGG∶xCr)2种多晶粉体(x=0.01,0.03,0.05,0.07)。并采用X射线衍射(XRD)、红外光谱(IR)、扫描电镜(SEM)、荧光光谱(PL)对样品的结构、组成、形貌和荧光性能进行测试分析。XRD和IR分析结果显示在900℃煅烧后Ga_2O_3∶xCr和YGG∶xCr两种样品均成相。SEM照片显示Ga_2O_3∶xCr样品形貌为柱形多面体,YGG∶xCr为短棒状。PL结果显示Cr~(3+)在Ga_2O_3和YGG两种基质中的最强荧光发射峰分别位于742和740 nm,均属于Cr~(3+)的~2E-~4A_2跃迁,对比发现Cr~(3+)在YGG基质中的荧光发射强度更强,在远红光区的荧光性能更好,能满足温室照明中植物光合作用的需求。     

Application of the “Tg-Δ rule” to the local structural study of ferrate glasses

A linear relationship exists between the glass transition temperature (T _g) and the quadrupole splitting (Δ) of Fe(III). The linear relationship, termed ‘T _g-Δ rule’, has been verified in 60CaO·(40-x)Al₂O₃·xFe₂O₃, 60CaO·10BaO·(30-x) Al₂O₃·xFe₂O₃, 60CaO·(40-x)Ga₂O₃·xFe₂O₃, and 50CaO·(50-x)Ga₂O₃·xFe₂O₃ glasses. In these glasses, both theT _g and Δ decrease linearly with an increasing content of Fe₂O₃ (≈40 mol%). The slope of the straight line, obtained from the plot of theT _g vs. Δ, was calculated to be 670≈700, °C/(mm·s⁻¹), revealing that the Fe(III) constitutes the skeleton of aluminoferrate and galloferrate glasses.     

Phase composition, electroconductivity, oxygen ion transport number, and microhardness of Ln1 ? xSrxGa0.5 ? y/2Al0.5 ? y/2MgyO3 ? δ (Ln = La, Pr, Nd; x, y = 0.10, 0.15)

Phase composition, electroconductivity, oxygen ion transport number, and microhardness of samples of Ln_{1 − x} Sr_xGa_{0.5 − y/2}Al_{0.5 − y/2}Mg_yO_{3 − δ} (Ln = La, Pr, Nd; x, y = 0.10, 0.15) synthesized by a ceramic methods are studied. Methods of x-ray diffraction analysis and scanning electron microscopy reveal the La-containing samples to be homogeneous and have a perovskite structure. Magnesium does not dissolve in Pr-and Nd-containing systems but forms an individual phase based on magnesium oxide. Apart from magnesium oxide, in these systems there form extrinsic phases, specifically, LnSrGa₃O₇ and an unknown phase. The electroconductivity of La_{1 − x} Sr_xGa_{1 − y} Mg_yO_{3 − δ} decreases after substituting Al for Ga. Ceramic La_{1 − x} Sr_xGa_{0.5 − y/2}Al_{0.5 − y/2}Mg_yO_3−δ is a purely ionic conductor in the temperature interval 500 to 1000°C; Nd_xSr_xGa_{0.5 − y/2}Al_{0.5 − y/2}Mg_yO_{3 − δ} has predominantly ionic conduction; and the predominant type of conduction in Pr_{1 − x} Sr_xGa_{0.5 − y/2}Al_{0.5 − y/2}Mg_yO_{3 − δ} is electronic below 700–800°C, with the contribution of ionic conduction increasing at higher temperatures. Substituting Al for Ga raises the hardness of ceramics under study. Among the compositions studied, La_0.85Sr_0.15Ga_0.45Al_0.45Mg_0.10O_{3 − δ} and La_0.85Sr_0.15Ga_0.425Al_0.425Mg_0.15O_{3 − δ} exhibit a combination of electroconductivity and hardness that is optimal for application as electrolyte at reduced temperatures (600–800°C). The Pr_{1 − x} Sr_xGa_{0.5 − y/2}Al_{0.5 − y/2}Mg_yO_{3 − δ} system possesses mixed ionic-electronic conduction and high hardness, which makes it appealing for application as oxygen-penetrable membranes. Original Russian Text ? Yu.V. Danilov, A.D. Neuimin, L.A. Dunyushkina, L.A. Kuz’mina, N.S. Zybko, Z.S. Martem’yanova, A.A. Pankratov, 2007, published in Elektrokhimiya, 2007, Vol. 43, No. 1, pp. 57–65.     

Crystal structure and high-temperature electrical conductivity of novel perovskite-related gallium and indium oxides

Novel complex oxides Sr₂Ga_1+x In_1?x O₅, x?=?0.0–0.2 with brownmillerite-type structure were prepared in air at T?=?1,273 K, 24 h. Study of the crystal structure of Sr₂Ga_1.1In_0.9O₅ refined using X-ray powder diffraction data (S.G. Icmm, a?=?5.9694(1) Å, b?=?15.2091(3) Å, c?=?5.7122(1) Å, χ ²?=?2.48, R _F ²? ₌?0.0504, R _p?=?0.0458) revealed ordering of Ga³⁺ and In³⁺ cations over tetrahedral and octahedral positions, respectively. A partial replacement of Sr²⁺ by La³⁺ according to formula Sr_1?y La _y Ga_0.5In_0.5O_2.5+y/2, leads to the formation of a cubic perovskite (a?=?4.0291(5) Å) for y?=?0.3. No ordering of oxygen vacancies or cations was observed in Sr_0.7La_0.3Ga_0.5In_0.5O_2.65 as revealed by electron diffraction study. The trace diffusion coefficient (D _T) of oxygen for cubic perovskite Sr_0.7La_0.3Ga_0.5In_0.5O_2.65 is in the range 2.0?×?10^?9–6.3?×?10^?8 cm²/s with activation energy 1.4(1)?eV as determined by isotopic exchange depth profile technique using secondary ion mass spectrometry at 973–1,223 K. These values are close to those reported for Ca-doped ZrO₂. High-temperature electrical conductivity of Sr_0.7La_0.3Ga_0.5In_0.5O_2.65 studied by AC impedance was found to be nearly independent on oxygen partial pressure. Calculated values of activation energy at T?<?1,073 K for hole and oxide-ion conductivities are 0.96 and 1.10 eV, respectively.     

Darstellung und Kristallstruktur des ersten polymeren Phosphorselenids catena-(P4Se4)x

Preparation and Crystal Structure of the First Polymeric Phosphorus Selenide catena-(P₄Se₄)_x Catena-(P₄Se₄)_x was prepared in crystalline form from the elements using iodine as a catalyst, and characterized by means of X-ray diffraction and IR spectroscopy. Single-crystal investigations (space group P2₁/c, a = 1 119.2(3), b = 728.2(2), c = 1 142.5(3) pm, β = 115.91(2)°, V = 837.5(7) · 10⁶ pm³) revealed parallel chains of P₄Se₃ hetero-norbornane units linked via Se atoms. Thus, being the first phosphorus selenide which does not contain discrete molecules, catena-(P₄Se₄)_x can be regarded as a polymeric form of α-P₄Se₄ or as a crystalline modification of vitrous phosphorus selenide.