17O MAS NMR study of 12-molybdophosphoric acid

¹⁷O MAS NMR spectra for¹⁷O enriched solid heteropoly acid H₃PMo₁₂O₄₀ are reported. The oxygen exchange between solid H₃PMo₁₂ ¹⁷O₄₀ and H₂ ¹⁶O vapor at 200–250°C is shown to be accompanied by fast mixing of terminal Mo=O and bridging Mo-O-Mo oxygens in the Keggin unit. The oxygen exchange in H₃PMo₁₂ ¹⁷O₄₀ is much faster than in H₃PW₁₂ ¹⁷O₄₀ in solution as well as in the gas phase.     

快固化、无收缩特种MMA-R17树脂在设备基础灌浆,锚固及修补中应用

本文介绍国外聚合物砂浆的性质和应用、施工配比及物理机械性能，供设计人员参考。     

Catalytic wall reactor: Catalytic coatings of stainless steel by VOx/TiO2 and Co/SiO2 catalysts

Catalytic wall (structured) reactors and structured supports are suitable to study the catalytic properties of nanosized materials. The coating of metallic (aluminum and stainless steel) plates by thin layers of active phase is presented in two cases, VO_x/TiO₂ and Co/SiO₂, catalysts used in the oxidative dehydrogenation (ODH) of propane and in Fischer–Tropsch synthesis (FTS) of clean fuels, respectively. The preparation of coated plates and their characterisation by various methods of physicochemical analysis are described. Both chemical and physical methods were used for coating. VO_x/TiO₂ layers were obtained by grafting of Ti (on Al or stainless-steel plates) and V (on TiO₂) alkoxides and use of sol–gel media or suspension. A silica primer was deposited (on stainless-steel plate) by plasma-assisted chemical vapour deposition (PACVD) onto which Co oxide and silica were coprecipitated from sol–gel. The catalytic experiments in the respective reactions were carried out in special plate reactors and compared with those of catalytic powders. The study shows that the coating of a metallic substrate by a catalyst is not straightforward and requires specific studies dealing with both chemistry (chemical affinity between substrate and catalytic layers) and catalytic engineering (catalytic performance in taylor-made reactors).     

Potassium–copper and potassium–cobalt catalysts supported on alumina for simultaneous NOx and soot removal from simulated diesel engine exhaust

This paper deals with the activity of bimetallic potassium–copper and potassium–cobalt catalysts supported on alumina for the reduction of NO_x with soot from simulated diesel engine exhaust. The effect of the reaction temperature, the soot/catalyst mass ratio and the presence of C₃H₆ has been studied. In addition, the behavior of two monometallic catalysts supported on zeolite beta (Co/beta and Cu/beta), previously used for NO_x reduction with C₃H₆, as well as a highly active HC-SCR catalyst (Pt/beta) has been tested for comparison. The preliminary results obtained in the absence of C₃H₆ indicate that, at temperatures between 250 and 400 °C, the use of bimetallic potassium catalysts notably increases the rate of NO_x reduction with soot evolving N₂ and CO₂ as main reaction products. At higher temperatures, the catalysts mainly favor the direct soot combustion with oxygen. In the presence of C₃H₆, an increase in the activity for NO_x reduction has been observed for the catalyst with the highest metal content. At 450 °C, the copper-based catalysts (Cu/beta and KCu2/Al₂O₃) show the highest activity for both NO_x reduction (to N₂ and CO₂) and soot consumption. The Pt/beta catalyst does not combine, at any temperature, a high NO_x reduction with a high soot consumption rate.     

DaWson型磷钨钒杂多酸催化合成苹果酯的研究

制备了Dawson型磷钨钒杂多酸催化剂，用Fr—IR分析方法对催化剂进行了结构表征，并以乙酰乙酸乙酯与乙二醇为原料催化合成了苹果酯。实验结果表明，磷钨钒杂多酸是合成苹果酯的理想催化剂，其较优反应条件为：乙酰乙酸乙酯0．1 mol，n（乙酰乙酸乙酯）：n（乙二醇）=1．0：1．5，催化剂的用量为反应物总质量的1．5％，12mL甲苯，回流反应3．0h，苹果酯的收率可达83．0％以上。     

Ni-Co双金属催化剂在二氧化碳重整甲烷反应中的催化活性研究

采用等体积浸渍法制备了Ni/BaTiO3、Co/BaTiO3和Ni-Co/BaTiO3催化剂,并在固定床反应装置上考察了在973~1 073 K这些催化剂对CO2重整CH4反应的催化活性,且采用程序升温还原技术对催化剂进行表征,发现与单金属催化剂相比,Ni-Co/BaTiO3双金属催化剂有更为优越的催化活性。结果表明在Ni-Co/BaTiO3催化剂中Ni和Co之间产生了一定的协同作用。同时研究了不同的制备方法对Ni-Co双金属催化剂催化活性的影响,用溶胶-凝胶法制备的催化剂具有更高的催化活性。     

Effect of structural and electrochemical properties of different Cr-doped contents of Li[Ni1/3Mn1/3Co1/3]O2

Layered Li[Ni_(1−x)/3Mn_(1−x)/3Co_(1−x)/3Cr_x]O₂ materials with x = 0, 0.01, 0.02, 0.03, 0.05 are prepared by a solid-state pyrolysis method. The oxide compounds were calcined with various Cr-doped contents, which result in greater difference in morphological (shape, particle size and specific surface area) and the electrochemical (first charge profile, reversible capacity and rate capability) differences. The Li[Ni_(1−x)/3Mn_(1−x)/3Co_(1−x)/3Cr_x]O₂ powders were characterized by means of X-ray diffraction (XRD), charge/discharge cycling, cyclic voltammetry, and SEM. XRD experiment revealed that the Li[Ni_(1−x)/3Mn_(1−x)/3Co_(1−x)/3Cr_x]O₂ (x = 0, 0.01, 0.02, 0.03, 0.05) were crystallized to well layered -NaFeO₂ structure. The first specific discharge capacity and coulombic efficiency of the electrode of Cr-doped materials were higher than that of pristine material. When x = 0.02, the sample showed the highest first discharge capacity of 241.9 mAh g⁻¹ at a current density of 30 mA g⁻¹ in the voltage range 2.3–4.6 V, and the Cr-doped samples exhibited higher discharge capacity and better cycleability under medium and high current densities at room temperature.     

水热法合成Co（C14H8O4）（C12H12N2）微晶粉体及初步表征

根据文献合成了联苯二甲酸,并通过水热法制备了Co（C14H8O4）（C12H12N2）暗紫色的微晶粉体。通过元素分析、IR等方法对配合物进行了表征,并通过TG分析对该配合物的热稳定性及热分解机理做了初步探讨。     

锂离子电池Si_(1.81)Co_(0.6)Cr_(0.6)Zn_(0.2)/MGS复合负极材料的制备与性能

采用两步高能球磨法制备了一种新的锂离子电池硅基复合负极材料Si1.81Co0.6Cr0.6Zn0.2/MGS.用X射线衍射(XRD)和扫描电镜(SEM)表征了材料的组成和形貌结构.电化学测试表明,Si1.81Co0.6Cr0.6Zn0.2/MGS作锂离子电池负极材料有较好的电化学性能:首次可逆容量为561 mAh.g-1,50个循环后,可逆容量的保持率为91%.Si1.81Co0.6Cr0.6Zn0.2/MGS循环性能的改善归因于电极结构在循环过程中的稳定性.     

球型Co2+印迹壳聚糖树脂的吸附特性及动力学研究

以Co2 和壳聚糖为原料,环氧氯丙烷和异丙醇为交联剂,制备了球形Co2 印迹壳聚糖树脂。研究了pH值、温度等因素对该印迹树脂吸附的影响及其吸附动力学。结果表明,pH值小于3.5时,印迹CTS树脂无吸附能力,pH值在3.5～6.0之间,印迹CTS树脂的吸附量随pH值升高而增大。印迹CTS树脂的吸附符合二级吸附动力学方程:t/Q=0.0077 0.0048 t。球形印迹壳聚糖树脂的吸附是以多分子层不均匀吸附模式为主,符合Freundlich方程。在30～90℃的温度范围内,树脂的吸附量随温度升高而增加,70℃时达到最大值,随后呈下降趋势。