石墨电极上硫化钠的阳极氧化机理探索

电解硫化氢气体的碱性吸收液（Ｎａ２Ｓ表示）产生单质硫和氢气的研究是治理硫化氢废气的一种新方法［１ -７］,较之Ｃｌａｕｓ法有许多优点［３,４］,这对环境保护和资源回收均具有重要的实际意义．文献对硫化物水溶液电化学氧化机理的研究主要着重于在某些贵金属阳极上,包括某些硫化矿的湿法冶金反应过程的研究［８,９］,光电化学电池中使用多硫化物的研究［１０ -１３］,以及硫化物电解时产生单质硫的电催化活性研究［１４］等 ;但在石墨阳极上硫化物电化学氧化机理的研究报导却很少［３,４］．本文研究在石墨阳极上硫化钠水溶液…     

4-[2-(4-N,N-二甲基苯胺基)乙烯基]吡啶氧化物的电化学行为

半菁染料是人们制造ＬＢ膜的材料之一．近年来,为得到电导率较高的薄膜,电荷转移络合物的ＬＢ膜受到重视［１］．实验证明,有机材料的ＬＢ膜经化学修饰或改性以后,电导率大大增加．化学工作者常将有机染料分子用来修饰电极,在光电化学、电催化等方面有较好的效果,因而,受到人们极大的关注．化学工作者已成功地制备出许多染料化学修饰电极,研究膜修饰电极的电化学行为［２,３］,而用循环伏安法和光谱技术对有机染料的电化学行为研究得较少［４,５］．本文对４ ［２ (４ Ｎ,Ｎ 二甲基苯胺基 )乙烯基］吡啶氧化物这个新改性的半菁化…     

聚(L-γ-氯乙基谷氨酸酯)的合成与构象

聚（Ｌ－γ－谷氨酸酯）类化合物是近年来被广泛用于蛋白质模拟及构象［１］、药物载体［２］和液晶大分子研究［３］,并可能是具有特殊场效应［４］的一类合成多肽．特别是在光电材料领域,人们发现将光致变色基团接入聚Ｌ－谷氨酸酯肽链的侧基是得到此类新型光电材料的最有效方法之一［５］．由于聚Ｌ－γ－谷氨酸酯是一类具有强旋光性的蛋白质,对其进行适当的改性后将对特定的小分子对映体有识别作用［６］,如将氨基糖接入聚Ｌ－谷氨酸酯的侧链就可制得能分离糖对映体的分离膜［７］．因此,将聚Ｌ－谷氨酸酯的侧链功能化,从而进一步…     

脲、硫脲固体电解质导电机理分析

高分子固体电解质（ＳＰＥ）是一类很有发展前途的功能高分子材料．在高比能电池、二次电池、光电池、传感器、电显色器、电容器等方面具有广泛的应用前景,受到国内外高分子科学界和电化学界的普遍关注［１］．目前的研究方向仍是寻找室温下高电导率的固体电解质材料［２,３］．我们［４－６］以脲和硫脲为主体,添加聚乙烯醇等高分子材料制成的ＳＰＥ,室温电导率可达６．８４ × １０-３ Ｓ·ｃｍ－１,但其导电机理尚不清楚．搞清其导电机理对于认识和改进此类电解质非常有益．１实验部分１．１ＳＰＥ的制备电解质由质量分数为５１％脲…     

一种双功能光折变模型分子的光电导性质

咔唑衍生物及含咔唑基团的聚合物由于在光信息传导、全息照相和光折变等高科技领域的潜在应用前景而越来越受到重视［１～３］,大量有机光折变材料已被合成．其中一些含有咔唑成分的光折变材料具有很优异的性能．１９９４年,一种具有低玻璃化温度的ＰＶＫ掺杂体系的净增益参数达到２２０ｃｍ－１,而衍射效率也近似达到１００％．这一结果超过了已知的绝大多数无机物［２］．大多数咔唑衍生物及含咔唑基团的聚合物都具有良好的光电导性质,并且主要以空穴传导为主．但它们的迁移率和机理由于引入不同的侧基和掺杂物出现很大差别［４～６］…     

Nb-MCM-41硅基中孔分子筛的合成与表征

ＭＣＭ４１中孔分子筛在催化、吸附分离、离子交换以及无机材料等领域具有较高的工程应用与研究价值．近年来,在催化应用方面,将具有一定催化活性的过渡金属元素如Ｔｉ［１］、Ｚｒ［２］、Ｍｏ［３］、Ｖ［４］、Ｆｅ［５］、Ｍｎ［６］、Ｗ［７］等以高分散的形态嵌入分子筛骨架结构中,得到了许多具有催化氧化性能的新型催化剂．这些新型催化剂已在石油加工、精细化学品和有机中间体的制备等方面显示出良好的应用前景［８］．铌的化合物是目前引人注目的一种新型催化材料,因为具有酸活性中心及氧化还原功能,已应用于烯烃齐聚［９］…     

可溶性聚对苯乙炔衍生物的合成

聚对苯乙炔（ＰＰＶ）具有独特的光电性能,经强氧化剂掺杂后是一类重要的导电材料［１］,而且具有良好的非线性光学（ＮＬＯ）性质［２］,也是目前性能最好的高分子电致发光材料［３,４］．可溶性的ＰＰＶ衍生物有望在显示领域广泛应用,从而成为电致发光领域研究的新...     

聚苯乙烯对酞菁铜颜料微胶囊化的研究

自１９５４年美国首先将微胶囊化应用于无碳复写纸后［１,２］,这项技术在药物、农药、食品及染料等方面已得到广泛应用［３］．微胶囊（ＭＣ）直径通常是１～５０００μｍ,构造分为囊壁和囊芯两部分［４］．囊壁材料大多使用高分子材料,少数用无机物［５］．有机颜料...     

由工业碲制备高纯碲

碲是制作半导体，制冷元件，光电元件等的理想材料．随着航天、航空、军事、电子以及制冷、玻璃、有机合成工业等的迅速发展，对碲及其化合物的需求量和纯度要求越来越高［１］．文献［２］所述制备高纯碲的方法为溶５０ｇ工业碲（９９．９％）于王水中，过滤．然后在滤液...     

锌酞菁掺杂C60在InP电极上的光电性能研究

Ｃ＿（６０）球烯是具有高度对称性的全碳原子簇，它既是电子受体，又是电子给体，表现出特有的光物理与光化学性能￣［１，２］．近十多年来众多的研究者对具有电子给体和电子受体的共轭π电子体系化合物在光照下的行为进行了深入研究￣［３］，认为用它作为有机光电子功能材料具有十分广阔的前景。随着人们对球烯研究的不断深入，尤其是宏观量球烯的合成与分离已日趋完善，以球烯为基础的有机光电材料必将越来越受到重视．金属酞青化合物由于拥有众多π电子的共轭体系，具有良好的光敏、半导体等性能，是较好的有机光电材料￣［４．５］．但在可见光区，其光敏性仍不够强，本文以ＺｎＰｃ掺杂Ｃ＿（６０）探索其光电性能，以期提高其光敏性．同类研究尚未见文献报道．     

钛凝胶的光致变色和电致变色特性

Titania gel is very sensitive to change of color to blue-purple by UV irradiation and to brown color under extra electric field polarzation. The UV absorption spectra of the photochromic (PC) and electrochromic(EC) titania gel are different to that of the nanocrystalline TiO_2 which changes to blue color by UV irradiation or under extra electric field polarization. The steady-state ESR measurements at room temperature indicate that ESR signals of Ti3+ appeared in PC and EC titania gel with the g values corresponding to 1.9505 and 1.9512, respectively.     

二氧化钛溶胶凝胶的光致变色

通过钛酸丁酯在酸性醇溶液中的水解制备二氧化钛溶胶和凝胶。在中压汞灯的照射下,溶胶和凝胶由浅黄色变成蓝紫色。电子自旋共振谱(ESR)表明,变色的原因是由于…Ti－O－Ti－O…网络中Ti^4^+离子被还原成Ti^3^+离子。Ti^3^+离子又会被空气中的氧所氧化成Ti^4^+离子,个人成分吏家产凝胶由蓝紫色褪为浅黄色。和变色溶胶的吸收光谱不同,在变色凝胶的吸收光谱上出现了四个明显的吸收峰,这些吸收峰是由于处于一定结构中的Ti^3^+离子的3d轨道上电子的跃迁所引起。     

Development of Photochromic Coatings on Polycarbonate

New photochromic materials based on heteropolyoxometallates (HPOM) incorporated into a hybrid organic-inorganic binder were prepared and coated onto polycarbonate (PC) substrates. The hybrid binder was formed through the controlled hydrolysis and condensation of 3-glycidoxypropyl-trimethoxysilane (GPTMS) and bisphenol A (BPA) by the sol–gel technique. The photochromic behavior of the materials was investigated by using ultraviolet-visible (UV-Vis) absorption spectroscopy and color index values. The results indicated that the films were reduced photochemically to yield a blue species under UV irradiation, with the film color changing to deep blue with increasing time, and HPOM and BPA content. The photosensitivity of several films with molybdenum HPOM showed faster coloration and much slower bleaching than the tungsten HPOM. A photochromic mechanism involving electron transfer between the GPTMS matrix with BPA, and PWO is proposed. After UV irradiation, the O–H and bonds decomposed gradually and W^{6 +} was reduced gradually with increasing time. The photochromic coatings on PC substrate showed reversible transmittance change before and after UV irradiation, making then efficient light protectors under UV irradiation.     

三氧化钼溶胶凝胶光致变色的研究

通过金属钼粉与过氧化氢溶液反应制备三氧化钼溶胶和凝胶,在高压汞灯的照射下,溶胶和凝胶由浅黄色变成蓝色。Raman光谱研究表明：通过紫外光照,MoO3凝胶结构进行了重整,呈有序排布。乙醇相的MoO3溶胶在紫外光照或长期自然光照下,均表现出光致变色特性。电子自旋共振(ESR)和X射线电子能谱(XPS)研究表明：空气中的MoO3经光照同时接受质子和电子后,生成了蓝色的钼青铜,其中Mo^6^+被还原成了Mo^5^+离子。     

Photoelectrochemical application of hollow titania film

In this study, hollow titania film (HTF) was prepared by a sol–gel spin-coating technique using titania coated nano carbon spheres as precursor suspension. The carbon spheres were synthesized by hydrothermal method using glucose as precursor. Photoelectrochemical property of HTF was examined by anodic photocurrent response, and results showed that the photocurrent of HTF was nearly twice as that of compact titania film (CTF). The photocatalytic and photoelectrochemical applications were investigated by using HTF or CTF as photoanodes for X-3B degradation under UV irradiation. Results showed that photocatalytic and photoelectrochemical activity of HTF enhanced a lot compared to CTF.     

Synthesis of TiO2 thin film by a modified sol-gel method and properties of the prepared films for photocatalyst

PTA (peroxo titanic acid) gel was prepared by a modified sol-gel method from peroxo titanic acid using TiCl₄/ethanol/water solution as the starting material at room temperature. Physicochemical properties of heat-treated gel were characterized by IR, XRD, TG-DTA and SEM. Optimal preparing conditions were chosen to prepare anatase film for the photocatalytic degradation of methyl orange. The dip-coating technique was used to synthesis the supported anatase film on quartz glass. Photocatalytic efficiency for the degradation of methyl orange under UV irradiation was also examined. It was found that the degradation efficiency of the anatase film synthesized in this paper is higher than commercial titania P25.     

EPR investigation of TiO2 nanoparticles with temperature-dependent properties

An in situ electron paramagnetic resonance (EPR) study has been carried out for anatase (Hombikat UV100) and rutile TiO(2) nanoparticles at liquid helium (He) temperature (4.2 K) under UV irradiation. Rutile titania was synthesized by ultrasonic irradiation with titanium tetrachloride (TiCl(4)) as the precursor. XRD and Raman results evidence the crystallinity of titania phases. The nature of trapped electrons and holes has been investigated by EPR spectroscopy under air and vacuum conditions. Illumination of TiO(2) powder (anatase and rutile) at 4.2 K resulted in the detection of electrons being trapped at Ti(4+) sites within the bulk and holes trapped at lattice oxide ions at the surface. The stability of electron traps was very sensitive to temperature in both phases of TiO(2). The annealing kinetics of the EPR detected radicals has been studied from 4.2 K to ambient temperature and also for calcined titania particles from 523 to 1273 K.     

Photoinduced hydrophilic conversion properties of titania nanosheets

Photoinduced hydrophilic conversion properties of titania nanosheets were investigated. A highly hydrophilic state was achieved on the monolayer film surface of titania nanosheets, the thickness of which is less than 1 nm. The hydrophilic conversion rate (k) for the monolayer film of titania nanosheets was proportional to the intensity (I) of irradiated light, suggesting that the hydrophilic conversion of the titania nanosheet surface proceeded under light-limited conditions even with a high concentration of photoexcited carriers. As the number of layers of titania nanosheets increased, the dependence behavior changed from k proportional, variant I(1.0) to k proportional, variant I(0.5), indicating that the recombination processes become dominant in the multilayer films of titania nanosheets. In-plane X-ray diffraction (XRD) analyses showed a very small but reproducible structural change of titania nanosheets upon UV irradiation.     

Flame synthesis of hierarchical nanotubular rutile titania derived from natural cellulose substance

Hierarchical nanotubular rutile titania material was fabricated by facile flame burning of ultrathin titania gel film coated cellulose nanofibres of commercial cellulose substance (filter paper), which possesses efficient photocatalytic performance for degradation of organic dye (methylene blue) under ultraviolet irradiation.     

Radiation-induced crosslinking of polyethylene in the presence of acetylene: A gel fraction,UV-visible,and ESR spectroscopy study

Electron-spin resonance (ESR) and altraviolet (UV) visible spectroscopic evidence has been found for the formation of diene, triene and tetraene, following the irradiation of polyethylene in the presence of acetylene. The polyenes are formed by a mechanism which is different from that observed under vacuum or with inert gas saturation. The sum of the G (polyene) values obtained by UV spectroscopy is almost half that of initial radical formation. It is concluded that polyene bridges, predominantly diene, form crosslinks between radical pairs. G (X) values determined from gel fraction data, using Saito-Kang-Dole theory, are found to be greatly in error and misrepresentative of crosslink changes. © 1993 John Wiley & Sons, Inc.