离子交换和热处理对贵金属掺杂硅酸盐玻璃光致发光的影响

贵金属纳米颗粒-玻璃复合材料是一种重要的非线性材料。利用光致发光谱及配位场理论, 深入研究了离子交换及氢气热处理对硅酸盐玻璃中贵金属离子的引入、还原、成核及生长过程的影响, 发现延长离子交换时间有利于提高玻璃中金属离子的浓度。对于掺Ag⁺硅酸盐玻璃, 不仅存在孤立Ag⁺离子, 同时也存在Ag₂⁺团簇。H₂中热处理后, 样品中孤立Ag⁺离子浓度迅速降低, 同时出现Ag₃²⁺团簇。对于掺Cu⁺硅酸盐玻璃, 仅存在孤立Cu⁺和Cu²⁺, 没有发现Cu⁺团簇的发光峰, Cu²⁺的存在造成Cu⁺的发光强度显著降低。掺Ag⁺硅酸盐玻璃经H₂热处理后, 再经过第二次离子交换往玻璃中掺Cu⁺是十分困难的。     

Cerium doped soda-lime-silicate glasses: effects of silver ion-exchange on optical properties

Effects of silver ion-exchange on optical absorption (OA) and photoluminescence (PL) spectra of a cerium doped soda-lime-silicate glass at room temperature are investigated. The optical spectra are described in terms of the characteristic transitions 4f↔5d originated in Ce³⁺ ions placed mainly in two different sites of the glass network. As Ag⁺ ions are introduced into the cerium doped glass, they are reduced to elementary silver (Ag⁰) which are favoured by the reaction Ce³⁺+Ag⁺→Ce⁴⁺+Ag⁰. Then, the number of Ce³⁺ ions decrease inversely with depth from the surface contrarily to Ce⁴⁺ ions does, and elementary silver diffuses and aggregates to form nanoparticles. As a consequence of these changes, the OA spectra of exchanged samples increase substantially in the UV range and the luminescence decreases significantly. The high sensitivity of PL together with deconvolution analysis of spectra, however, allows us to detect changes in the excitation and emission spectra from the earlier stages of ion-exchange. This indicates that during the ion-exchange we deal with fast processes (much shorter than 1 min). In fact, transmission electron microscopy observations of samples from the glass exchanged for a short time as 1 min at 325°C show the presence of a scanty number of silver nanoparticles, which confirms this point. Furthermore, with increasing the length of time of ion-exchange, PL spectra exhibit a progressive red shift indicative in part of a covalence increment in the oxygen–cerium coordinated bonding. We observe no luminescence from Ag⁺ ions and other silver molecular species in contrast with other preliminary PL studies on silver ion-exchange in soda-lime-silicate glasses free of cerium. The effect is discussed on the basis of a supplementary increase in the number of Ce⁴⁺ ions mainly due to the reaction Ce³⁺+Ag⁺→Ce⁴⁺+Ag⁰, which prevents efficiently the luminescence of the silver centers.     

One pot synthesis of monodispersed L-glutathione stabilized gold nanoparticles for the detection of Pb2+ ions

Direct mixture of Au³⁺ with glutathione (GSH), which act as both reduction agents and stabilizers, in aqueous solution gave rise to production of gold nanoparticles (Au NPs) with uniform sizes of around 21 nm. The GSH stabilizer Au NPs in solution show immediate aggregation after addition of 1 mol/L NaCl aqueous solution containing Pb²⁺ ions. The Pb²⁺-induced aggregation in Au NP solution is monitored by both colorimetric response and UV-vis spectroscopy. A rather broad linear range (from 0.1 to 30 μmol/L) and low detection limit (0.1 μmol/L) are explored for Au NP sensors used for detection of Pb²⁺ ions. Furthermore, the response of GSH-stabilized Au NPs toward Pb²⁺ ions is specific compared with other possible interferants (Hg²⁺, Mg²⁺, Zn²⁺, Ni²⁺, Cu²⁺, Co²⁺, Ca²⁺, Mn²⁺, Cd²⁺, and Ba²⁺).     

焙烧温度对Cu-Mn/γ-Al2O3催化剂催化氧化甲苯性能的影响

采用浸渍法合成了Cu-Mn/γ-Al₂O₃催化剂, 通过XRD、BET、H₂-TPR和XPS等方法对经不同温度(300~600℃)焙烧的催化剂进行表征, 采用固定床管式反应装置考察了焙烧温度对催化剂催化氧化甲苯的影响, 并讨论活性组分、表面Cu⁺/(Cu⁺+Cu²⁺)和Mn⁴⁺/(Mn⁴⁺+Mn³⁺)摩尔比值与催化剂活性的关系。结果发现, 550℃焙烧温度的催化剂活性最好, 氧化能力最强, 其转化率为95%时对应的反应温度T₉₅(286 ℃)最低, CO₂的选择性达100%。在550℃焙烧时生成的Cu_1.4Mn_1.6O₄新相以及催化剂表面中相对含量更高的Cu⁺和Mn⁴⁺是催化剂具有高活性的主要原因。     

AC impedance spectroscopy of porous silicon thin films containing metallic cations

Thin porous silicon (PS) films were prepared by HF/HNO₃ vapor etching on silicon wafers. The infiltration of metallic cations inside the porous silicon matrix followed by slow heating in air leads to an interesting electrical and optical physical phenomena. Al³⁺, Cu⁺, K⁺, Li⁺ metallic cations as chloride or as nitrate solutions are infiltrated inside the silicon porous matrix. After annealing in air at 500 °C during 2 h a structure was achieved in order to measure the Nyquist diagram corresponding to the cations embedded in PS/silicon. The real and imaginary parts of the whole structure depend on the voltage bias and on the frequency. Those signify that the junction is a Schotky-barrier junction.

From the variation of Ln(σT) versus absolute temperature T, where σ is the conductivity, we have deduced the activation energy of the metallic impurities in the [100 °C–400 °C] temperature range. We have found that the activation energies are of about 0.19 eV, 0.25 eV, 0.49 eV and 0.71 eV for Cu⁺, K⁺, Al³⁺ and Li⁺ cations respectively. These kinds of structures are suitable for gas sensing, optical sensing or for the fabrication of fuel cell membranes.     

γ辐照及热退火对光热折变玻璃光学性能的影响

对光热折变(Photo-thermal-refractive, PTR)玻璃在总剂量分别为0.35、1、10及100 kGy的γ射线下辐照, 并进行热退火处理, 采用吸收光谱、光致发光光谱及EPR电子顺磁共振谱研究了光热折变玻璃在γ射线辐照下的辐照机理。研究结果表明, γ辐照后的PTR玻璃在可见波段的吸收主要由银原子Ag⁰、银分子簇Ag₂、银分子簇Ag₃、银纳米颗粒Ag_m⁰及非桥氧空穴中心HC₁及HC₂引起; 在不同剂量γ射线辐照下, 玻璃基质中的变价离子(Ag⁺、Ce³⁺)价态先发生变化, 同时玻璃基质中的非桥氧键发生电离, 形成了非桥氧空穴型缺陷中心HC₁、HC₂。进一步增加辐照剂量, 产生了银的分子簇Ag₂和Ag₃; 同时玻璃基质中非桥氧空穴中心HC₂的浓度增大, 导致在639 nm附近的吸收增强。分别在不同温度下对辐照后的PTR玻璃进行相同时间的热处理及在低于T_g(玻璃转变温度)的温度下进行不同时间的热处理, 观察到250 ℃退火后PTR玻璃中HC₁及HC₂缺陷中心发生漂白; 并在430 ℃退火后出现了银纳米颗粒的吸收峰, 该吸收峰随退火时间的延长发生了红移及展宽。     

Optical and structural characterizations of Cu-doped KCl films

The production of highly Cu⁺-doped KCl films and the properties of their 266 nm absorption band, which has an off-center property in doped single crystals, open the possibility of application of these films as ultra-violet optical filters. The investigated films, of approximately 1 μm thickness, were prepared by resistive co-evaporation of KCl and CuCl powders on different substrates of CaF₂, Al₂O₃, SiO₂, KCl and Si. The Cu⁺ concentration, as determined by energy-dispersive X-ray, ranges from 10²⁰ to 10²¹ cm⁻³, for 1–15% CuCl nominal mole percent concentration. Structural and optical properties were investigated through scanning electron microscopy, X-ray diffraction, ellipsometry, optical absorption and transmission. The films are polycrystalline, and the gain size decreases with increasing Cu⁺ impurity concentration, yielding an increase of visible transmission to a limited CuCl concentration. These films show a 6.295 Å lattice parameter with a f.c.c. structure and an index of refraction of 1.53 at 266 nm. When the Cu⁺ concentration is increased, the UV band position remains the same and no clusters are evidenced even to the high 15% CuCl concentration investigated, which differs very much from single crystals samples grown by the Kyropoulos-Czochralski method. For a Cu⁺ concentration of 8×10²⁰ cm⁻³ the film shows a transmission better than 88% at 350 nm wavelength.     

水泥熟料固化重金属Cu2+和Zn2+及水化浸出行为分析

危废处理是当前的热点问题,水泥窑协同处置作为一种有效的处理方式,逐步为社会所接受。多数的危废中包含Cu²⁺和Zn²⁺,文章研究了危废中重金属Cu²⁺和Zn²⁺在水泥熟料中的固化性能和在熟料中的分布,并探讨了重金属在水泥净浆中的浸出行为和环境安全性。通过熟料易烧性X射线衍射(XRD),矿物相分离萃取,浸出实验得出:Cu²⁺和Zn²⁺均改善了熟料易烧性;Cu²⁺促进了C₄AF的生成,同时也促进了C₃S晶粒的生长,并固溶在其中;Zn²⁺与熟料形成新的矿物相Ca₁₄Al₁₀Zn₆O₃₅。通过相对分布系数(D)和分配系数(K_f)说明Cu²⁺主要分布在硅酸盐相中,硅酸盐相固化Cu²⁺的能力强于中间相;Zn²⁺主要分布在中间相中,中间相固化Zn²⁺的能力强于硅酸盐相。掺量为2.0%的Cu²⁺和Zn²⁺在水泥净浆7 d龄期的浸出浓度最大,分别为1.724和0.387 mg·L^-1。水泥熟料固化Cu²⁺和Zn²⁺在水泥使用过程中不会对环境造成二次污染。     

NaCu3Ti3Sb0.5Ta0.5O12陶瓷的高介电性质及相关机制的研究

在不同烧结温度下, 利用传统的固相反应工艺制备了一系列NaCu₃Ti₃Sb_0.5Ta_0.5O₁₂陶瓷, 系统测试了它们的晶体结构、微观结构、介电性质和复阻抗谱。结果显示, 所有的NaCu₃Ti₃Sb_0.5Ta_0.5O₁₂陶瓷的主相都呈现类钙钛矿结构, 介电性质随烧结温度变化很大。高于1020℃烧结的陶瓷的室温相对介电常数大于3000, 具有高介电性质。复阻抗谱显示, NaCu₃Ti₃Sb_0.5Ta_0.5O₁₂陶瓷的电学分布不均匀, 由绝缘性的晶界和半导性的晶界组成。通过XRD和XPS测试发现, 在陶瓷中观察到了CuO第二相和Cu、Ti、Sb、Ta离子的变价。因此, 利用内阻挡层电容效应可以解释NaCu₃Ti₃Sb_0.5Ta_0.5O₁₂陶瓷的高介电性质。     

Glass formation and conductivity in the Pb2P2O7–Ag4P2O7–AgI system

A large glass-forming domain has been identified in the Pb₂P₂O₇–Ag₄P₂O₇–AgI system. The physical properties have been determined as a function of AgI content. The ionic conductivity has been studied as a function of the Ag⁺ ion total concentration and the Ag⁺ ion concentration issued from the AgI component. The structure and electrical properties of obtained glasses are compared with those of ionic glasses of the Ag₄P₂O₇–AgI system.     

低温制备不锈钢表面含铜磷酸铝涂层及抗菌性能研究

利用磷酸二氢铝的固化反应在316不锈钢表面制备了不同含量Cu²⁺的磷酸铝涂层(Cu: Al=0.025、0.05、0.1)。差示扫描量热分析及X射线衍射表明涂层材料可在≤250℃下固化, 主要固化产物为AlH₂P₃O₁₀∙2H₂O、AlPO₄和Al₈H₁₂(P₂O₇)₉。Cu²⁺加入后产生了含铜的新相Cu₂P₂O₇。与大肠杆菌共培养12 h后各含Cu²⁺涂层表现出抗菌性, 且抗菌能力与Cu²⁺含量正相关; 接触24 h后, 所有含Cu²⁺涂层表面均无活菌检出。菌悬液中加入EDTA有效抑制了涂层抗菌活性, 表明涂层抗菌性能来自表面溶出的Cu²⁺。拉伸试验表明涂层结合强度在14.5~18.1 MPa范围。与无涂层的不锈钢相比, 涂覆涂层后样品的腐蚀电流密度下降了2个数量级。     

Structural properties of swift heavy ion beam irradiated Fe/Si bilayers

The Fe/Si multilayers were prepared by electron beam evaporation in a cryo-pumped vacuum deposition system. Ag⁺ and Au⁺ ions of 100 MeV at two different fluencies such as 1 × 10¹² ions/cm² and 1 × 10¹³ ions/cm² at a pressure of 10^− 7 torr were used to irradiate the Fe/Si samples. The irradiated samples were analyzed by High-Resolution XRD and it reveals that the irradiated films are having polycrystalline nature and it confirms the formation of the β-FeSi₂. The structural parameters such as crystallite size (D), strain (ε) and dislocation density (δ) have been evaluated from the XRD spectrum. The role of the substrates and the influence of swift heavy ions on the formation of β-FeSi₂ have been discussed in this paper.     

Mn,Cu掺杂对ZnS∶Mn,Cu电致发光材料亮度的影响

采用水热法制备了ZnS∶Mn,Cu电致发光材料,利用透射电镜对发光材料的结构和形貌进行表征,并且探讨了Cu2+、Mn2+掺杂量和反应温度对ZnS∶Mn,Cu发光材料亮度的影响。结果显示,随着Cu2+、Mn2+掺杂量的增加,发光材料的亮度也随之增加,但对于Cu2+、Mn2+掺杂都存在最佳值,当Cu2+掺杂量0.2%,Mn2+掺杂量4%,温度150℃时,得到的电致发光材料亮度较高,粒径约10nm左右。     

Cloud point extraction for the determination of copper, nickel and cobalt ions in environmental samples by flame atomic absorption spectrometry

A cloud point extraction procedure was presented for the preconcentration of copper, nickel and cobalt ions in various samples. After complexation with methyl-2-pyridylketone oxime (MPKO) in basic medium, analyte ions are quantitatively extracted to the phase rich in Triton X-114 following centrifugation. 1.0 mol L⁻¹ HNO₃ nitric acid in methanol was added to the surfactant-rich phase prior to its analysis by flame atomic absorption spectrometry (FAAS). The adopted concentrations for MPKO, Triton X-114 and HNO₃, bath temperature, centrifuge rate and time were optimized. Detection limits (3 SDb/m) of 1.6, 2.1 and 1.9 ng mL⁻¹ for Cu²⁺, Co²⁺ and Ni²⁺ along with preconcentration factors of 30 and for these ions and enrichment factor of 65, 58 and 67 for Cu²⁺, Ni²⁺ and Co²⁺, respectively. The high efficiency of cloud point extraction to carry out the determination of analytes in complex matrices was demonstrated. The proposed procedure was applied to the analysis of biological, natural and wastewater, soil and blood samples.     

核-壳纳米Ag@ZrO_2复合材料的制备及其抑菌性能

首先,采用溶胶-凝胶法以锆酸四丁酯为原料制备了直径约为230nm单分散性ZrO_2亚微球;然后,以ZrO_2为前体,加入少量AgNO3,用物理方法将Sn2+离子吸附在ZrO_2表面,Ag+被还原成Ag0负载在ZrO_2表面合成Ag@ZrO_2晶种,加入甲醛合成核-壳纳米Ag@ZrO_2复合材料;最后用TEM、XRD和UV-Vis对制备的ZrO_2和Ag@ZrO_2进行表征,并研究其对金黄色葡萄球菌(S.aureus)和大肠杆菌(E.coli)的抑菌性能。结果表明:当Ag浓度为0.6mg/mL时,Ag@ZrO_2对S.aureus和E.coli的抑菌率分别为95.5%和99.0%。因此,Ag@ZrO_2作为理想的抗菌材料可以应用于日常生活和医疗实践中。     

Fe3O4/高岭土磁性复合材料对Cu2+的吸附性能

为实现高岭土（Kaolin）在Cu²⁺废水处理中的实际应用,采用球磨方法制备了剥离Kaolin,并通过氧化沉淀法制备了Fe₃O₄/Kaolin磁性复合材料。通过激光粒度分析仪、SEM、XRD对Fe₃O₄/Kaolin磁性复合材料的形貌及组成进行表征,并通过测试Fe₃O₄/Kaolin磁性复合材料对Cu²⁺的饱和吸附量和磁分离回收率,确定了当Kaolin球磨4.0 h、掺量为3.0 g时所制备的Fe₃O₄/Kaolin磁性复合材料对Cu²⁺的吸附性能最佳,平衡吸附量为17.98 mg/g。磁滞回线结果表明,Fe₃O₄/Kaolin磁性复合材料具有较好的磁响应性,饱和磁化强度约为16.19 emu/g。此外,采用Langmuir和Freundlich吸附等温式对Fe₃O₄/Kaolin磁性复合材料的吸附数据进行拟合,结果表明,Fe₃O₄/Kaolin磁性复合材料对Cu²⁺的吸附行为基本符合Langmuir吸附等温模型和Freundlich吸附等温模型,既存在单分子层吸附,也存在多分子层吸附。     

一种新型膦酸锆孔材料的合成及其对金属离子的吸附性质

骨架含强配位基的有机无机杂化多级孔材料合成是目前吸附研究的一个重要领域。以bis (hexamethylene) triamino-N, N-bisacetyl-phosphonic acid和ZrOCl₂·8H₂O为原料、应用水热合成技术合成了一种新型膦酸锆多级孔材料ZrPTA, 并通过FT-IR、TGA、XRD、XPS、SEM以及元素分析等手段对制备产物进行了表征。研究结果表明, ZrPTA具有棒状微形貌, 其内部存在大量直径为1.38 nm和1.93 nm的微孔以及直径为2.99 nm的介孔, 其表面积为112.2 m²/g。ZrPTA对水溶液中Pb²⁺、Cu²⁺和Cd²⁺三种金属离子具有良好的吸附作用, 最大吸附量分别为742.7、689.8和627.0 mg/g, 远远高于文献报道值。这一性质使ZrPTA具有潜在的废水处理功效, 显示出诱人的应用前景。     

铜离子掺杂Y2Ba2O5高近红外反射颜料的制备和光学性能研究

采用溶胶-凝胶法制备一系列环境友好型绿色近红外反射纳米颜料, 结构通式为Y₂Ba_(2-x)Cu_xO₅(x=0、0.25、0.50、0.75和1.0), 通过X射线衍射(XRD)、扫描电子显微镜(SEM)、UV-vis-NIR分光光度仪和高精度分光测色仪对制备颜料的结构、形貌和光学性能进行了表征。研究结果表明, 铜离子掺杂进入Y₂Ba₂O₅晶格中, Y₂Ba₂O₅晶粒尺寸由62.1 nm降低至54.7 nm。Cu²⁺取代Y₂Ba₂O₅中的部分Ba²⁺, 粉末颜色由白色变为绿色(a*=-21.61), 禁带宽度由2.30 eV 减少到2.04 eV; 粉末呈现不规则球形结构, 粒径分布在150~300 nm范围内。掺杂Cu²⁺使粉末的近红外反射率降低, 但Cu²⁺掺杂量为x=0.50时仍然表现出较高的近红外反射率(68.80%)和太阳光反射率(45.95%)。因此, Y₂Ba_(2-x)Cu_xO₅系列高近红外反射绿色粉末作为“冷”颜料在建筑涂料方面具有巨大的应用潜能。     

磁性硅铁载铜吸附Hg0动力学机制及密度泛函研究

采用粉末冶金法将纳米单质铜(Cu⁰)、硅铁(FeSi)、四氧化三铁硅涂层(Fe₃O₄@SiO₂)混合煅烧并制备出新型磁性硅铁载铜吸附剂MagFeSi-Cu⁰。实验研究不同烟气温度下MagFeSi-Cu⁰的汞吸附能力基础上,结合颗粒内扩散模型、准二阶动力学模型、Elovich模型及Bangham模型分析了MagFeSi-Cu⁰吸附Hg⁰过程的主要控制步骤。在此基础上,依据密度泛函理论(DFT)研究了不同反应温度下FeSi表面Cu⁰原子与Hg⁰原子的汞齐作用机制。研究结果表明,Bangham模型的拟合值与MagFeSi-Cu⁰汞吸附实验值拟合度最高,MagFeSi-Cu⁰表面痕量Hg⁰吸附由汞的外扩散和表面铜汞齐吸附共同控制;通过密度泛函计算,发现Cu⁰颗粒表面Cu-Hg齐吸附能为-0.534 eV,当烟气温度从80℃上升至200℃时,Hg⁰原子与单质Cu原子的吸附自由能从-22.47 kJ/mol下降至-13.96 kJ/mol,这些结果为深入了解Hg⁰在Cu(111)表面的反应机理提供了理论基础。     

载银沸石应用的研究进展

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