新型咪唑啉化合物在H_2S/CO_2共存条件下对Q235钢的缓蚀性能

合成了一种新型咪唑啉化合物1-(2-氨基-硫脲乙基)-2-十五烷基-咪唑啉(IM-S),并通过失重法、电化学方法及扫描电镜等研究了IM-S在H2S/CO2共存条件下对Q235钢的缓蚀性能,探讨了其在Q235钢表面的吸附行为.结果显示,IM-S具有较好的抗H2S、CO2腐蚀能力,能同时抑制碳钢腐蚀的阴、阳极反应过程,最高缓蚀效率可达92.74%.缓蚀剂在Q235钢表面呈单分子层吸附,属于以化学吸附为主的混合吸附.最后采用量子化学方法对IM-S的缓蚀机理做了进一步分析.     

A3钢在芽孢杆菌作用下的腐蚀行为

采用表面分析技术、失重法和电化学测试技术研究了A3钢在芽孢杆菌(Bacillus)作用下的腐蚀行为.扫描电子显微镜(SEM)分析结果表明,浸泡7d时,芽孢杆菌会在A3钢表面形成致密的生物膜,有效阻隔了溶液对基体的腐蚀,抑制了腐蚀过程.电化学交流阻抗测试结果显示,含菌体系中的试样表面经历了2个时间常数→3个时间常数→2个时间常数的变化过程.失重法和极化曲线测试结果表明,芽孢杆菌的细菌活性对生物膜的保护作用有着决定性的影响,当微生物活性下降,生物膜的保护能力也会大幅降低.     

Mechanical properties and frictional resistance of Al composites reinforced with Ti_3C_2T_x MXene

Two-dimensional(2D) Ti_3C_2T_x MXene is an attractive additive not only used in base oil due to its low friction coefficient,but also used in composites due to its high aspect ratio and rich surface functional groups.So far there has been intense research into polymer matrix composites reinforced with Ti_3C_2T_x,Here we report on the use of 2D Ti_3C_2T_x to enhance the mechanical and frictional properties of Al matrix composites.Ti_3C_2T_x/Al composites were designed and prepared by pre s sureless sintering followed by hot extrusion technique.The prepared composites exhibit a homogeneous distribution of Ti_3C_2T_x.The Vickers hardness and the tensile strength continuously increase with increasing Ti_3C_2T_x content.A hardness of 0.52 GPa and a tensile strength of 148 MPa were achieved in the 3 wt% Ti_3C_2T_x/Al composite.The frictional properties of pure Al and the Ti_3C_2T_x/Al composite were comparably studied under dry sliding.A low friction coefficient of 0.2,twice lower than that of pure Al,was achieved in the 3 wt%Ti_3C_2T_x/Al composite.Ti_3C_2T_x acting as a solid lubricant reduces the abrasive wear in the composite,improving the frictional properties of Al matrix composites.     

Ti:Al2O3纳米粉体的共沉淀法合成及表征

本文采用共沉淀法合成了Ti:Al2O3纳米粉体.利用热重/差热(TG/DTA)/X射线衍射(XRD)/红外光谱(FTIR)/扫描电镜(SEM)以及能谱(EDS)等分析方法对合成的Ti:Al2O3纳米粉体进行了表征.结果分析表明:前驱体在1200℃下,保温1h可以得到纯的α-Al2O3晶相;粉体的粒径均匀、分散性好,平均粒径在25～50 nm之间.     

Preparation and electrochemical properties of Co3O4-coated layered manganese oxide by a novel coating method

Potassium type birnessite (K-bir) was synthesized by O₂ oxidizing Mn²⁺ in aqueous solution of KOH. Co₃O₄-coated K-bir (Co-K-bir) was prepared by employing a novel coating method, in which the remaining OH⁻ ions on the particle surface of the as-precipitated K-bir reacted with Co²⁺ ions in aqueous solution, forming CoOOH coverage; the coating layer of CoOOH was subsequently annealed at 300 °C to transform into Co₃O₄. All the K-bir and Co-K-birs were investigated by scanning electron microscopy, transmission electron microscopy, inductive coupled plasma–atomic emission spectroscopy, Brunauer–Emmett–Teller specific area, and laser particle size analyzing techniques. Their electrochemical properties were also studied by discharging–charging at constant current. The results show that the covering layers of Co₃O₄ are incompact, and their average thickness are about 0.65–0.78 μm. Compared to the as-prepared and the annealed K-bir, the Co₃O₄-coated samples have higher initial discharge capacities and show distinctly improved cycleability performance.     

Investigation of the incorporation of electrolyte anions in porous anodic Al2O3 films by employing a suitable probe catalytic reaction

A new method has been developed capable of describing the incorporation of electrolyte anions along the pore wall surface and across both the barrier layer and the pore wall oxide after the establishment of the steady state of growth of porous anodic Al₂O₃ where other methods cannot be applied to obtain reliable results. The knowledge of the nature/composition of anodic oxides as regards the incorporation of species like electrolyte anions is of specific importance for both the understanding of the electrochemical mechanism of oxide production and growth and the scientific and technological applications of porous anodic Al₂O₃ films. The method consists of the selection and use of a suitable catalytic probe reaction on porous anodic oxides at thicknesses varying from a value near zero up to the maximum limiting thickness and the treatment of the experimental reaction rate results by a properly developed mathematical formalism. This method was employed in anodic Al₂O₃ films prepared in H₂SO₄ anodizing electrolyte at a constant bath temperature and different current densities using as a probe reaction the decomposition of HCOOH on these oxides, which is almost exclusively a dehydration reaction, at relatively high reaction temperatures, 350 °C and 390 °C, where the effect of other species except SO₄ ²⁻ incorporated in the oxide on the reaction rate is eliminated. It has been shown that the fraction of the intercrystallite surfaces occupied by SO₄ ²⁻ follows a parabola-like distribution. It has a significant value at the pore base surface, depending on the current density, then it passes through a maximum along the pore wall surface and across both the barrier layer and the pore walls near the pore bases at positions depending on the current density and then becomes almost zero at the mouths of the pores of the oxide with the maximum limiting thickness and at both the Al₂O₃/Al interface and cell boundaries. The maximum value of the surface coverage is almost independent of the current density and is always near 1, showing an almost complete saturation of intercrystalline surfaces at these positions. The above distribution of surface coverage predicts a qualitatively similar distribution of the SO₄ ²⁻ bulk concentration across both the barrier layer and pore wall oxide around the pore bases. The method may be improved and developed further either for a more detailed investigation of the above films or to investigate films prepared in other pore-forming electrolytes. Received: 30 July 1998 / Accepted: 30 September 1998     

ZrO2引入对Pd/Al2O3催化剂结构和性能的影响

Pd催化剂;Zr/Al混合氧化物;甲烷催化燃烧     

Preparation of Ni3B2O6 nanosheet-based flowerlike architecture by a precursor method and its electrochemical properties in lithium-ion battery

A novel flower-like nickel borate of Ni₃B₂O₆ nanostructure was prepared through a hydrothermal treatment and sequential thermal decomposition of precursor without employing any template or surfactant. All the samples were characterized by XRD, IR, XPS, TG–DTA, nitrogen adsorption, SEM and TEM. The flower-like Ni₃B₂O₆ nanostructure was self-assembled by nanosheets with the thickness of about 40 nm. The electrochemical properties in lithium-ion battery of flower-like Ni₃B₂O₆ nanostructure were studied by the cyclic voltammetry, galvanostatic cycling test, and electrochemical impedance spectroscopy, which showed it had a high initial discharge capacity and a good reversibility.     

化学沉积Ni-P-Al2O3和Ni-P-SiC复合材料的微观组织与物理性能

采用化学沉积方法,可以制备以镍磷合金为基质的复合硬质相粒子的复合材料［１］．镍磷合金颇受青睐之处在于可以调整成分和时效处理温度来改变其组织结构,进而获得广泛变化的性能［２,３］．本文报道化学沉积获得的ＮｉＰ氧化铝和ＮｉＰ碳化硅复合材料的微观组织与...     

有机配体修饰纳米Al2O3的合成及性质研究

合成了以β-二酮配体3-甲基-1-苯基-4-(十八烷基酰基)吡唑啉酮-5(PMOP)修饰的Al2O3纳米粒子,并用IR、UV光谱、NMR和荧光光谱等手段进行了表征.修饰后的Al2O3纳米粒子能溶于氯仿、乙醇和甲苯等常见有机溶剂,并有较强的蓝色荧光.表明在一些无机纳米粒子的表面键合上有机配体后,可以产生新的光物理性质.修饰后的Al2O3纳米粒子还可作为支架材料用于准固态染料敏化纳米晶太阳能电池中.     

吡啶、CO和SO2在Al2O3/SiO2混合氧化物复合纳米晶上的TPD

程序升温脱附;吡啶、CO和SO2在Al2O3/SiO2混合氧化物复合纳米晶上的TPD     

Enhanced dielectric performance and energy storage of PVDF‐HFP‐based composites induced by surface charged Al2O3

In order to enhance dielectric properties and energy storage density of poly(vinylidene fluoride‐hexafluoro propylene) (PVDF‐HFP), surface charged gas‐phase Al₂O₃ nanoparticles (GP‐Al₂O₃, with positive surface charges, ε’ ≈ 10) are selected as fillers to fabricate PVDF‐HFP‐based composites via simple physical blending and hot‐molding techniques. The results show that GP‐Al₂O₃ are dispersed homogeneously in the PVDF‐HFP matrix and the existence of nanoscale interface layer (matrix‐filler) is investigated by SAXS. The dielectric constant of the composites filled with 10 wt % GP‐Al₂O₃ is 100.5 at 1 Hz, which is 5.6 times higher than that of pure PVDF‐HFP. The maximum energy storage density of the composite is 4.06 J cm^?3 at an electrical field of 900 kV mm^?1 with GP‐Al₂O₃ content of 1 wt %. Experimental results show that GP‐Al₂O₃ could induce uniform fillers’ distribution and increase the concentration of electroactive β‐phase as well as enhance interfacial polarization in the matrix, which resulted in enhancements of dielectric constant and energy storage density of the PVDF‐HFP composites. This work demonstrates that surface charged inorganic‐oxide nanoparticles exhibit promising potential in fabricating ferroelectric polymer composites with relatively high dielectric constant and energy storage. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 574–583     

(Ag/Al2O3+Cu/Ce(x)/Al2O3)组合催化剂催化乙醇选择性还原NOx及其副产物的消除

制备了Cu/Ce(x)/Al2O3(x为Ce与Al的摩尔比)系列氧化催化剂,并考察了(Ag/Al2O3 Cu/Ce(x)/Al2O3)组合体系催化乙醇还原NOx以及氧化去除反应副产物(CO和未完全燃烧的碳氢化合物)的活性.在200～350℃温度区间,组合催化剂具有与Ag/Al2O3相似的NOx去除效率.随着Ce/Al比增加,氧化催化剂去除CO的活性逐渐提高.Cu/CeO2催化剂具有最好的氧化活性,但其对NOx的去除有较大影响.综合考虑NOx转化率以及CO和HC的去除效果,(Ag/Al2O3 Cu/Ce(0·15)/Al2O3)是最佳的催化剂组合体系.通过对此系列氧化催化剂的BET比表面积、XRD、H2-TPR以及XPS等表征结果的分析,发现Cu和Ce之间的相互作用是催化剂氧化CO能力提高的主要原因.     

Enhanced electrochemical properties of a novel polyvinyl formal membrane supporting gel polymer electrolyte by Al2O3 modification

Polyvinyl formal (PVFM)‐based dense polymer membranes with nano‐Al₂O₃ doping are prepared via phase inversion method. The membranes and also their performances as gel polymer electrolytes (GPEs) for lithium ion battery are studied by field emission scanning electron microscope, X‐ray diffraction, differential scanning calorimetry, mechanical strength test, electrolyte uptake test, electrochemical impedance spectroscopy, cyclic voltammetry, and charge–discharge test. The polymer membrane with 3 wt % nano‐Al₂O₃ doping shows the improved mechanical strength of 12.16 MPa and electrolyte uptake of 431.25% compared with 10.47 MPa and 310.59% of the undoped sample, respectively. The membrane absorbs and swells liquid electrolyte to form stable GPE with ionic conductivity of 4.92 × 10^?4 S cm^?1 at room temperature, which is higher than 1.77 × 10^?4 S cm^?1 of GPE from the undoped membrane. Moreover, the Al₂O₃‐modified membrane supporting GPE exhibits wide electrochemical stability window of 1.2–4.8 V (vs. Li/Li⁺) and good compatibility with LiFePO₄ electrode, which implies Al₂O₃‐modified PVFM‐based GPE to be a promising candidate for lithium ion batteries. © 2014 Wiley Periodicals, Inc. J. Polym. Sci. Part B: Polym. Phys. 2014 , 52, 572–577     

硫代硫酸铵预硫化的MoO3／Al2O3催化剂的活化和加氢脱硫活性

以硫代硫酸铵为硫化剂对MoO3/Al2O3催化剂进行预硫化,考察了制备方法和活化条件对预硫化催化剂噻吩加氢脱硫活性的影响. 结果表明,硫代硫酸铵预硫化的催化剂活化后,加氢脱硫活性好,噻吩的转化率达到99%以上,而二甲基二硫硫化的MoO3/Al2O3催化剂在相同条件下,噻吩转化率只有92%. 合适的活化温度为200～300 ℃, 活化压力增加有利于预硫化催化剂的还原硫化和加氢脱硫活性的提高. 硫代硫酸铵预硫化催化剂的高脱硫活性主要归因于多层的Ⅱ型MoS2活性相的形成,其次是硫化程度的提高. 硫代硫酸铵预硫化催化剂经过氢气活化和补充硫化两个阶段,其硫化程度高于传统方法硫化的催化剂.     

氢气对Ag/Al2O3和Cu/Al2O3催化剂选择性催化C3H6还原Nox反应的影响

 添加H2对Ag/Al2O3和Cu/Al2O3催化剂选择性催化C3H6还原NOx反应具有不同的影响. 原位漫反射红外光谱分析表明,在Ag/Al2O3催化剂上, H2的存在促进了C3H6部分氧化产物烯醇式物种(RCH=CH-O-)和乙酸盐等的形成,烯醇式物种和硝酸盐为主要反应中间体,二者间的相互反应性能很强,能形成高浓度的反应关键中间体异氰酸酯(-NCO)表面吸附物种,因此NOx的去除活性提高; 而在Cu/Al2O3催化剂上, H2的存在并没有促进C3H6部分氧化产物的形成,而且抑制了硝酸盐的形成,进而抑制了C3H6部分氧化产物与硝酸盐反应形成表面-NCO 物种,导致NOx的去除活性降低.     

ICP-AES法测定铁矿中的CaO、MgO、Al2O3和MnO

用电感耦合等离子发射光谱仪（ICP-AES）测定了铁矿中的CaO、MgO、Al2O3和MnO，用钇内标元素校正基体干扰，对分析谱线、共存元素、酸性条件等进行了讨论。     

SrO对Al2O3载体的改性及MnOx/SrO-Al2O3催化剂的甲烷燃烧活性

以Mn(CH3COO)2为前驱体，制备了MnOx/Al2O3,MnOx/SrO-Al2O3系列催化剂，考察了SrO对Al2O3热稳定性的影响及MnOx/SrO-Al2O3催化甲烷燃烧的活性，并用X－射线衍射（XRD），程序升温还原（TPR）对其进行了表征，结果表明，随SrO加入量的增加复合载体SrO-Al2O3的比表面发生明显变化，高温焙烧过程中生成SrAl2O4,SrO.6Al2O3,SrO的加入抑制了Al2O3的α相变，SrO-Al2O3(1000℃焙烧）负载的MnOx催化剂，其还原性能有较大提高，对甲烷燃烧的催化活性明显增强。     

CaF2-Al2O3-MgO电渣微结构的原位拉曼光谱及27Al魔角旋转核磁共振研究

运用原位拉曼光谱和 ²⁷Al魔角旋转核磁共振研究了CaF₂-Al₂O₃-MgO电渣重熔渣晶体、 玻璃和熔体的微结构及铝配位数的变化. 利用X射线粉末衍射分析获得该晶体样品中存在的物相, 分别基于密度泛函理论及量子化学从头算分析了S-6530晶体和熔体中相关物相的拉曼振动波数及散射活性, 并对其主要振动模式进行了归属. 结果表明, S-6530晶体中铝主要以六配位形式存在, 并有少量的四、 五配位. 在升温过程中, 其中MgAl₂O₄物相的Al-O多面体由[AlO₆]转变成[AlO₄]与[AlO₅]共存. Al在熔体和玻璃结构中主要以[AlO₄]四面体的形式存在, 其占比高达71.1%, 相较于其晶态, [AlO₅]的占比也增加至28.6%. 基于构建的熔体团簇模型的量子化学从头算表明, [AlO₄]构型倾向于以Q₃, Q₄连接方式为主的层状和架状结构, 而[AlO₅]构型则倾向于单体形式.     

Physical properties and electrochemical performance of LiMn2O4 cathode materials prepared by a precipitation method

LiMn₂O₄ powder for lithium-ion batteries was prepared by a precipitation method, and the effects of calcination temperature on the physical properties and electrochemical performance of the samples were investigated by various methods. The results of X-ray diffraction (XRD) showed that the lattice parameter (a) and the unit cell volume (v) decrease with the increasing calcination temperature, and the LiMn₂O₄ sample calcined at 750°C has smaller particle size and higher crystallinity than other samples. The results of the electrochemical experiments showed that the sample calcined at 750°C has larger peak currents, higher initial capacity, and better cycling capability, because of its lower charge-transfer resistance and larger diffusion coefficient of Li⁺ ions than those of other samples.