CuO–ZnO Micro/Nanoporous Array‐Film‐Based Chemosensors: New Sensing Properties to H2S

CuO–ZnO micro/nanoporous array‐films are synthesized by transferring a solution‐dipped self‐organized colloidal template onto a device substrate and sequent heat treatment. Their morphologies and structures are characterized by X‐ray diffraction, field‐emission scanning electron microscopy, transmission electron microscopy, and X‐ray photoelectron spectrum analysis. Based on the sensing measurement, it is found that the CuO–ZnO films prepared with the composition of [Cu²⁺]/[Zn²⁺]=0.005, 0.01, and 0.05 all show a nice sensitivity to 10 ppm H₂S. Interestingly, three different zones exist in the patterns of gas responses versus H₂S concentrations: a platform zone, a rapidly increasing zone, and a slowly increasing zone. Further experiments show that the hybrid CuO–ZnO porous film sensor exhibits shorter recovery time and better selectivity to H₂S gas against other interfering gases at a concentration of 10 ppm. These new sensing properties may be due to a depletion layer induced by p–n junction between p‐type CuO and n‐type ZnO and high chemical activity of CuO to H₂S. This work will provide a new construction route of ZnO‐based sensing materials, which can be used as H₂S sensors with high performances.     

Characterization of the patina formed on a low tin bronze exposed to aqueous hydrogen sulfide

The dark gray corrosion layer (patina) formed on the surface of a polished low tin bronze alloy following exposure to a deoxygenated and saturated aqueous solutions of H₂S has been characterized by X‐ray photoelectron spectroscopy, scanning electron microscopy‐energy dispersive spectroscopy and X‐ray diffraction. The system represents a model for bronze corrosion in reducing conditions where sulfate‐reducing bacteria in soils or deoxygenated seawater may generate H₂S during respiration. The initial surface was dominated by metallic copper together with Sn, Pb and Zn oxides and hydroxides. Surface enrichment of Pb and Zn was noted because of a smearing effect during polishing. At least some of the lead was crystalline. In contrast, the corrosion layer formed by H₂S(aq) exposure was dominated by polycrystalline Cu₂S (low and high chalcocite) and smaller concentrations of CuSO₄ · nH₂O. This surface was enriched with Zn as Zn(OH)₂. Lead was present as redeposited PbS (galena) crystallites in at least two different morphologies. Unlike bronzes exposed to oxidizing conditions, which develop protective SnO₂ layers, the H₂S(aq)‐exposed surface was considerably depleted in Sn. Copyright © 2014 John Wiley & Sons, Ltd.     

Preparation and characterization of polyphenylene sulfide-based chelating fibers

A series of novel chelating fibers containing sulfur, nitrogen, oxygen heteroatoms were prepared via the functionalization of chloromethylated polyphenylene sulfide （CMPPS）. The structures, micromorpholo- gy and physicochemical properties of these fibrous adsorptive materials were characterized by FT-IR, elementary analysis, TG and SEM-EDS. The results show that chelating fibers had high functional group contents （3.94 mmol/g for thiourea, 3.85 mmol/g for mercapto, 5.00 mmol/g for methylamine and 6.07 mmol/g for ethylenediamine, respectively）. Owing to the unique matrix of polyphenylene sulfide fiber, these fibrous adsorbents possess excellent thermostability. This synthetic method proved a simple and efficient way for the preparation of chelating fibers.     

二维气相色谱法分析天然气水合物区沉积物间隙水中示踪气体的浓度

利用微流路控制技术中心切割装置(Deans Switch)、两根色谱柱(PoraPLOT Q和Molsieve 5A)和3个检测器(脉冲氦离子化检测器、火焰光度检测器、热导检测器),建立了一种二维气相色谱分析系统,实现了海洋中多种示踪气体组分(氢气、甲烷、二氧化碳、硫化氢)的同时分析和精确测定。氢气、甲烷、二氧化碳、硫化氢的含量分别在2～1030、0.6～501、120～10500和0.2～49.1 μmol/mol范围内的校正曲线线性关系良好,检出限分别为0.51、0.17、82和0.08 μmol/mol,10次重复测定含量的相对标准偏差均小于10%。通过对南海天然气水合物区沉积物间隙水顶空气的测定,表明该方法方便、灵敏、可靠,易于实现海上现场测定;与以往采用多种分析方法分别测定示踪气体相比,大大节省了样品量。该方法适用于海洋天然气水合物、海底热液等资源的调查和海洋溶解态气体的研究等。     

Ag2S/Al2O3纳米复合物的水热合成及表征

采用水热技术结合煅烧的方法,成功制备了Ag2S/Al2O3纳米复合物。 通过SEM、EDX、XRD等测试技术对产品进行了表征,证明得到的产品是Ag2S/Al2O3纳米复合物;无孔Al2O3和多孔Al2O3作反应模板得到的复合物的形态和分布不同。     

Synthesis of Ni2P promoted trimetallic NiMoW/γ-Al2O3 catalysts for diesel oil hydrotreatment

The Ni2P promoted and γ-Al2O3 supported NiMoW sulfide catalyst consisting of 4 wt% Mo, 22 wt% W, 2 wt% Ni and 2.5 wt% Ni2P was synthesized by a co-impregnation method. The catalysts were characterized by N2 adsorption-desorption, X-ray diffraction (XRD), diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy, NH3 temperature-programmed desorption (NH3-TPD) and transmission electron microscopy (TEM). The results showed that Ni2P, Ni, Mo and W species were highly dispersed over γ-Al2O3. The hydrodesulfurization (HDS) of dibenzothiophene (DBT) showed that the presence of Ni2P brought a strong promotional effect on the HDS activity, which was further confirmed by the HDS and hydrodenitrogenation (HDN) of diesel oil under industrial conditions. The enhancement in HDN activity and stability by Ni2P addition could be attributed more to the effect of new active sites of Ni2P than that of acidity modification. The as-prepared Ni2P-NiMoW/γ-Al2O3 catalyst showed better hydrotreating performance than NiMoW/γ-Al2O3 and commercial catalysts.     

TS3000总硫分析仪分析低压力硫化氢的研究

通过时TS3000 总硫分析仪气体进样模块的简单改装,利用仪器的富集功能,使其可以分析由质量流量控制器原理发生的低含量、低压力的硫化氢气体,解决了TS3000 总硫分析仪不能检测压力较低样品的难题.对不同含量硫化氢样气体的分析结果表明,改装后的仪器仍具有很好的线性及准确度,同时验证了仪器改装方法的可行性.     

Influence of substrate activation process on structural and optical properties of ZnS thin films

ZnS thin films were deposited on glass substrates by a chemical bath deposition method using a substrate activation process in which aluminum ions become “contaminants” that act as a nucleation center for active components within the deposition solution. The structure and morphology results demonstrate that the films have a ZnS sphalerite crystal structure with a particle size less than 15 nm, and the films consist of small homogeneous grains. The effects of the substrate activation process on the band gap energies and donor-acceptor pair luminescence process were also investigated. A green emission centered at 502 nm was produced due to donor-acceptor transitions from the aluminum acceptor to the ionized and substitution aluminum centers (Al³⁺).     

THE STAUDINGER REACTION BETWEEN 2-H-1,2,3-DIAZAPHOSPHOLENES AND AROMATIC AZIDES

Abstract

The title reaction between substituted phenyl azides 2 and diastereomeric diazaphospholenes 1 gives the corresponding cyclic phosphazenes 3 with different stereochemical results. Hydrolysis of some phosphazenes 3 yield the corresponding ring-opened compounds Z-4I together with small amounts of diazaphospholene-oxide 5 and anilines 6. The configuration of the compounds obtained are established by ¹H n.m.r. spectroscopy. The results are explained invoking the formation of pentacoordinate phosphorus intermediates.     

Immobilization of [Pt2(μ-S)2(PPh3)4] on Polymeric Supports by Sulfide Alkylation and Phosphine Exchange Reactions

Abstract

The immobilization of the dinuclear platinum(II) sulfido complex [Pt₂(μ-S)₂ (PPh₃)₄] on solid supports has been investigated. Reaction with haloalkyl functionalized polymers [Merrifield's resin (chloromethylated polystyrene), chloropropyl silica, chloropropyl controlled pore glass, and bromopropyl polysiloxane] gives complexes immobilized through alkylation of one of the sulfide ligands, forming a μ-thiolate ligand acting as an anchor to the polymer support, akin to well-established reactions of [Pt₂(μ-S)₂(PPh₃)₄] with molecular alkylating agents. The model complex [Pt₂(μ-S)(μ-SCH₂SiMe₃)(PPh₃)₄]PF₆ was prepared as the first molecular silicon-containing derivative of [Pt₂(μ-S)₂(PPh₃)₄] and was fully characterized by NMR spectroscopy, electrospray ionization-mass spectrometry, and single-crystal X-ray diffraction. Immobilization of [Pt₂(μ-S)₂(PPh₃)₄] by phosphine exchange reactions was also achieved using commercial polystyrene-grafted triphenylphosphine or a new immobilized phosphine [derived by sequential functionalization of Merrifield's resin with a polyether amine and then Ph₂PCH₂OH].