Optical ammonia gas sensor based on a porous silicon rugate filter coated with polymer-supported dye

An ammonia gas sensor chip was prepared by coating an electrochemically-etched porous Si rugate filter with a chitosan film that is crosslinked by glycidoxypropyltrimethoxysilane (GPTMS). The bromothylmol blue (BTB), a pH indicator, was loaded in the film as ammonia-sensing molecules. White light reflected from the porous Si has a narrow bandwidth spectrum with a peak at 610 nm. Monitoring reflective optical intensity at the peak position allows for direct, real-time observation of changes in the concentration of ammonia gas in air samples. The reflective optical intensity decreased linearly with increasing concentrations of ammonia gas over the range of 0–100 ppm. The lowest detection limit was 0.5 ppm for ammonia gas. At optimum conditions, the full response time of the ammonia gas sensor was less than 15 s. The sensor chip also exhibited a good long-term stability over 1 year. Therefore, the simple sensor design has potential application in miniaturized optical measurement for online ammonia gas detection.     

Solvent‐Free Synthesis of Benzothiazolines in the Presence of Alumina

o‐Aminothiophenol reacted with ketones and β‐keto esters in the presence of alumina under mild and solvent‐free conditions to afford the corresponding benzothiazolines in high yields. Alumina can be reused for subsequent reactions without any loss of the activity.     

An Efficient General Synthesis of Squarate Esters

An efficient and general method for the synthesis of alkyl squarates is presented. This involves the reactions of squaric acid with the desired alcohol in the presence of an orthoformate. This was applicable for the synthesis of dimethyl-, diethyl-, diisopropyl, di-n-butyl and di-t-butyl squarates in yields ranging from 77–97%. It is a convenient and safe method that can be accomplished on a multigram scale.     

六棱柱状多晶γ-Al2O3的制备、表征及其形成机制研究

以AlCl₃·6H₂O为前驱物,在氨水介质中用水热法制备了具有新颖形貌特征的六棱柱状多晶γ-Al₂O₃颗粒。采用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)及N₂物理吸脱附等方法对所制备的γ-Al₂O₃颗粒进行了表征,并对其形貌形成机制进行了分析。结果表明,铝前驱物在氨水介质中通过水热处理后,经焙烧可以形成形貌规整的六棱柱状γ-Al₂O₃颗粒,其边长与长度分别约为0.3 μm和2.5 μm。TEM图片显示,六棱柱颗粒是由尺寸在10 nm左右的粒子聚集而成,因而具有多晶γ相特征。所制备的γ-Al₂O₃材料具有发达的孔隙结构,比表面积为274 cm²/g,孔容为0.51 cm³/g,孔径集中分布在5.5 nm周围。研究发现,γ-Al₂O₃六棱柱形貌的形成机制与AlOOH二次粒子在NH₄⁺正电荷作用下发生的最稳态排列形式具有密切的关联。     

Alumina‐Incorporated Polyesteramide from Non‐Edible Seed Oils

To improve the physico‐mechanical and chemical resistance properties, lower the curing temperature of annona squamosa and pongamia glabra seeds oils based polyesteramides [ASPEA, PGPEA], as well as to convert the non‐edible seed oils into value added products, their respective alumina‐incorporated polyesteramides resins [Al‐ASPEA, Al‐PGPEA] have been synthesized. The resins and their coatings have been tested for their chemical, physico mechanical and chemical/corrosion resistance properties. These properties were compared among the prepared resins and with that of previously reported alumina filled linseed polyesteramide [Al‐LPEA]. It was observed that Al‐PGPEA‐71, which has the highest amount of oleic acid chains, shows the best physico‐mechanical and chemical resistance properties.     

多孔金属有机骨架材料储氢性能分子模拟

采用优化的DREIDING力场参数, 通过巨正则系综蒙特卡洛(GCMC)模拟方法对H₂在IRMOF-1、IRMOF-61和IRMOF-62共3种金属有机骨架(MOFs)材料中的吸附平衡性能进行了比较研究. 结果表明, 该力场能够在全压力范围内很好地复制H₂在IRMOF-62材料中的等温吸附曲线; 但对低压下H₂在IRMOF-61中的等温吸附曲线预测出现低估. 与IRMOF-1相比, 具有互穿骨架结构的IRMOF-61和IRMOF-62材料在常温下的储氢能力并无明显提高. 进一步比较77 K时100 kPa、3.0 MPa下H₂在上述MOFs材料中达到吸附平衡时的几率密度分布发现, H₂会优先吸附在Zn₄O骨架附近靠近苯环的位置;对具有互穿结构的MOFs材料而言,由于其孔腔尺寸缩小, 使得H₂优先吸附位区域零散化. 适当长度的有机配体形成的互穿骨架结构能增强与H₂分子之间的相互作用, 具备较高的储氢能力; 而有机配体尺寸过长则会增加骨架结构中H₂吸附死角, 对H₂的吸附能力反而出现下降.     

A study on the system of nonaqueous microchip electrophoresis with on‐line peroxyoxalate chemiluminescence detection

This article describes a further development of our previously reported miniaturized analysis system of microchip electrophoresis with on‐line chemiluminescence detection. The system, developed first time for nonaqueous microchip electrophoresis with peroxyoxalate chemiluminescence detection, consists of a suction pressure device for sample or reagent introduction, a constant voltage supplied for electrophoretic separation, an either hydrophilic or hydrophobic porous polymer plug for preventing chemiluminescence reagent flowing upstream and a spiral detection channel for enhancement of both detection sensitivity and reproducibility. Especially, by using organic solvent as BGE medium, the developed system avoided the interface problem between aqueous running buffer and low‐water‐content chemiluminescence solvent in previous reports. The influencing factors on chemiluminescence signal were optimized using rhodamine 6G as model molecule. The system performance was further investigated in the experiment of separation of hydrophilic rhodamine dyes and analysis of hydrophobic polycyclic aromatic hydrocarbon, providing the detection limit (S/N = 3) of 3.5 nmol/L for rhodamine 123, 6.8 nmol/L for rhodamine 6G, and 60 nmol/L for 1‐aminopyrene, respectively. The experimental results showed the system offered a number of benefits, including compact structure, high sensitivity, good reproducibility, and a wide range of application prospect.     

载体对Ni_2P催化剂加氢脱氮反应性能的影响

使用TiO2、Al2O3以及TiO2-Al2O3复合载体考察了载体对磷化镍催化剂活性相和加氢脱氮性能的影响。不同钛铝原子比的TiO2-Al2O3复合载体采用原位-溶胶凝胶法制备,负载的磷化镍催化剂采用等体积浸渍法和H2原位还原法制备。以喹啉为模型化合物在固定床反应器上对催化剂的加氢脱氮性能进行评价,采用XRD、N2吸附、TEM和H2-TPR等技术对催化剂和载体进行了表征。结果表明,制成的复合载体基本保留了最初引入的γ-Al2O3的孔特征,分散在γ-Al2O3表面的TiO2以锐钛矿晶型存在。不同载体对催化剂的H2还原行为有显著影响,所形成的活性物种也不相同。Al2O3中引入TiO2可以减弱P物种和Al2O3之间的相互作用,有利于Ni2P活性相的生成和催化活性的提高。当Ti/Al的原子比为1∶8时,Ni2P/TiO2-Al2O3催化剂比Ni2P/TiO2、Ni2P/Al2O3催化剂具有更高的加氢脱氮活性。     

多孔材料的研究进展

本文总结了2010~2013国际和国内在无机微孔材料领域的研究进展和亮点,比较了国内外研究的进展,展望了本领域的发展趋势。全文共引用参考文献87篇。     

Photoluminescence properties of heat-treated porous alumina films formed in oxalic acid

Photoluminescence and optical properties of as-anodized and heat-treated at 500 °C porous alumina films formed in a 0.3 M oxalic acid at 40 V have been studied. The FTIR indicates that the oxalate ions are embedded in the anodic alumina as chelating bidentate structures and further heating up to 500 °C does not cause any change in ion coordination. The results of time-resolved spectroscopy show the presence of two luminescence centers both in the as-anodized and heat-treated anodic alumina films with lifetimes of about 0.25 and 4.0 ns. The F⁺-centers in anodic alumina are responsible for the luminescence peak at about 420 nm, with a lifetime of about 4.0 ns. The luminescence peak at about 480 nm, with lifetime of about 0.25 ns, can be attributed to the luminescence of carboxylate ions existing in bulk of anodic alumina.