Vx-Mn0.8Fe0.2O2催化剂的制备及其抗硫脱硝性能

为了更好地适应工业化脱硝需求,选用廉价的黑色金属Mn和Fe作为催化剂主要原料,通过V掺杂极大地提升了锰铁催化剂的低温脱硝性能和抗硫性能。采用共沉淀法制备了V_x-Mn_0.8Fe_0.2O₂催化剂,运用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和X射线光电子能谱分析(XPS)考察了V₂O₅添加量对Mn_0.8Fe_0.2O₂催化剂的结构、形貌及其抗硫脱硝性能的影响。结果表明:V_x-Mn_0.8Fe_0.2O₂催化剂主要物相为Mn₂O₃,样品颗粒尺寸小且分散均匀。V_0.3-Mn_0.8Fe_0.2O₂催化剂具有较多的活性位点及较好的抗硫脱硝性能,在300℃时脱硝率可达90.36%,相比于Mn_0.8Fe_0.2O₂催化剂脱硝性能达到90%的温度约降低100℃;同时,在V(CO):V(NO):V(SO₂)为3:1:1的反应条件下,催化剂的脱硝率仍能保持在80%以上。     

B2O3含量对SiO2–B2O3–Al2O3–Na2O系陶瓷结合剂结构与性能的影响

制备不同B₂O₃含量的SiO₂–B₂O₃–Al₂O₃–Na₂O系玻璃试样和陶瓷结合剂试样,利用电子多功能实验机、扫描电镜、显微硬度仪、平面流淌法、热膨胀系数测试仪等分别测试不同玻璃试样的密度和显微硬度,陶瓷结合剂试样的抗折强度、微观形貌和热膨胀系数等,并用X射线衍射仪、傅里叶变换红外光谱仪对陶瓷结合剂的结构和成分变化进行分析。结果表明:将B₂O₃引入陶瓷结合剂中可有效降低其烧结温度,提高其热稳定性并调节其热膨胀系数等。在陶瓷结合剂中加入摩尔分数为15%的B₂O₃时,其样条抗折强度最高为78.11 MPa,密度和硬度最高分别为2.45 g/cm3和856 MPa,且该陶瓷结合剂的热膨胀系数与金刚石最匹配。X射线衍射分析结果表明陶瓷结合剂是典型的玻璃相结构,且对磨料有良好的包覆效果。      

CeO2/ZrO2-Y2O3纳米结构热障涂层的高温稳定性及耐腐蚀性能

采用等离子喷涂方法（APS）在GH30高温合金表面分别制备了纳米ZrO₂-8%Y₂O₃（YSZ,质量分数）和掺杂25%（质量分数）纳米CeO₂的三元CeO₂/ZrO₂-8%Y₂O₃（CSZ）热障涂层.使用FESEM和XRD分析了涂层的微观组织,研究了CSZ涂层在1100℃加热条件下分别保温不同时间及固定加热时间10 h,改变加热温度时涂层晶粒尺寸的变化情况,测试了2种涂层在高温下的耐Na₂SO₄熔盐腐蚀能力.结果表明,CSZ涂层在高温长时间加热时,平均晶粒尺寸从喷涂态的45 nm增至63 nm,变化较小,在900℃,Na₂SO₄熔盐腐蚀条件下长时间加热无m-ZrO₂相析出,耐蚀性能要高于YSZ涂层.     

NiCrAlY/Al-Al2O3/Ti2AlNb高温抗氧化和力学性能研究

采用电弧离子镀技水在NiCrAlY涂层与O相Ti₂AlNb合金之间沉积不同Al:Al₂O₃比例的Al-Al₂O₃薄膜作为扩散阻挡层.研究了900℃下恒温氧化500 h后NiCrAlY/Al-Al₂O₃/Ti₂AlNb体系中Al-Al₂O₃层阻挡合金元素互扩散的行为,以及对涂层氧化动力学曲线的影响.结果表明,没有添加扩散阻挡层的NiCrAlY/Ti₂AlNb体系,涂层和基体之间的元素互扩散十分严重,涂层丧失抗氧化能力;而添加扩散阻挡层的材料体系,涂层和基体之间的元素互扩散受到抑制,涂层的长期抗高温氧化性能得到提高.对于3Al-Al₂O₃,1Al-Al₂O₃和0Al-Al₂O₃ 3种扩散阻挡层,综合比较材料体系的抗氧化性能、阻挡层阻挡涂层和基体元素互扩散能力、以及涂层和基体之间结合力,当1Al-Al₂O₃薄膜作为扩散阻挡层时,材料性能最优异.同时,本文利用扩散阻挡系数简洁定量地表示出不同Al:Al₂O₃比例阻挡层的阻挡扩散能力.     

低冰镍衍生的具有高结构稳定性和快速扩散动力学的钠离子掺杂层状LiNi1/3Co1/3Mn1/3O2正极(英文)

通过共沉淀法合成钠离子(Na⁺)掺杂的高稳定性Li_1-xNa_xNi_1/3Co_1/3Mn_1/3O₂(NCM-Na)正极材料。首先论证采用低冰镍提取镍作为合成材料镍源的可行性。其次,在化学试剂合成的NCM(Ni,Co,Mn)材料中预先引入最优含量的Na⁺,占据部分Li⁺位点,实现具有更低Li⁺/Ni²⁺阳离子混排的稳定结构,从而提高其电化学性能。结果表明,当Na⁺掺杂量为1%(质量分数)(x=0.01)时,获得的NCM-Na正极材料在1C电流密度下,循环100次后容量保持率从76.84%提高至89.21%。特别是在5C大电流密度下,循环200次后,可逆放电比容量依然维持在110 mA·h·g^-1。这为杂原子掺杂耦合材料化冶金开发低成本、高性能锂离子电池三元LiNi_1/3Co_1/...     

Ni-Cu掺杂诱导制备两类截角八面体LiMn2O4材料及其电化学性能

结合元素掺杂和晶面调控策略制备了同时包含(111)、(110)和(100)三个晶面和包含(111)和(100)两个晶面的两类截角八面体形貌的LiNi_0.03Cu_0.06Mn_1.91O₄正极材料，并研究了其电化学性能。结果表明：Ni-Cu共掺杂有效抑制了尖晶石LiMn₂O₄的Jahn-Teller效应，促进了其晶体发育和晶面的择优生长，但部分晶面发育较不完善，与一般情况不同的是Ni-Cu共掺后LiNi_0.03Cu_0.06Mn_1.91O₄正极材料的颗粒粒径显著增大；形成的截角八面体形貌中高暴露(111)面降低了Mn的溶解，少部分(110)和(100)晶面增加了Li⁺的扩散通道。恒电流充放电测试结果表明：在5 C和10 C倍率下，LiNi_0.03Cu_0.06Mn_1.91O₄     

一种可内生Al2O3扩散障的δ-Ni2Al3-Cr2O3/ Ni-Cr2O3涂层体系

通过对Ni-Cr₂O₃复合镀层620 ℃部分渗铝制备了δ-Ni₂Al₃-Cr₂O₃/Ni-Cr₂O₃涂层体系。Cr₂O₃颗粒在渗铝的过程中和Al反应生成更为稳定的Al₂O₃。1000 ℃恒温氧化20 h后发现,铝化物涂层和复合镀层内掺杂的Cr₂O₃颗粒完全转化为Al₂O₃,并在铝化物涂层/Ni镀层界面自发形成了一层Al₂O₃富集层,该富集层起扩散障作用,阻碍铝化物涂层因互扩散所致的退化。     

Na2O对NaF-AlF3低温电解质中Al2O3溶解性能的影响

本文研究了添加Na₂O的Al₂O₃在NaF-AlF₃低温电解质中的溶解速度。通过氧分析仪对电解质中不同时间段的氧化铝浓度进行测定，经过计算获得电解质中氧化铝的溶解速度。研究结果表明：在NaF-AlF₃低温电解质体系中，在氧化铝中加入Na₂O可以显著提高氧化铝在电解质中的平均溶解速度，氧化铝中Na₂O含量越高，平均溶解速度越快。当熔盐温度升高时，NaF-AlF₃中氧化铝溶解速度逐渐加快。氧化铝平均溶解速率取决于实验0～5 min时间段内电解质中氧化铝溶解量。     

等离子喷涂法制备Ti/Ti4O7+TiB2/PbO2阳极材料的性能研究

用等离子喷涂法在钛基体上喷涂一层Ti₄O₇和TiB₂的混合物作为中间过渡层,以提高钛基体的耐蚀性能、改善钛基体的导电性;然后在Ti/Ti₄O₇+TiB₂中间过渡层上电镀PbO₂活性层,从而制备出一种新型的"三明治"结构的钛阳极。实验结果表明:喷涂后的钛基体主要由TiO₂、Ti₄O₇和TiB₂三种物相组成;TiB₂的加入能够显著提高Ti/Ti₄O₇的导电性;当TiB₂含量为15%左右时,该电极材料的电化学性能达到最佳。     

优化水热合成提高ZnMn2O4阳极的储锂性能(英文)

为探讨制备条件对过渡金属氧化物负极材料电化学性能的影响，以硝酸锌和硝酸锰为原料，采用水热法合成了过渡金属氧化物ZnMn₂O₄负极材料。通过设计4因素3水平的正交试验，系统研究反应温度、反应时间、致密度、pH值等工艺参数对合成条件的影响。X射线衍射和扫描电镜证实ZnMn₂O₄具有微米级块状结构及I41/amd空间群。在优化的制备条件下，Li/ZnMn₂O₄电池的首次放电比容量为933.1 mA·h/g，在0.1C倍率下循环100次后放电比容量仍为249.3 mA·h/g。正交优化后的样品具有良好的循环性能和倍率性能。     

Facile synthesis of high capacity P2-type Na2/3Fe1/2Mn1/2O2 cathode material for sodium-ion batteries

P2-type Na_2/3Fe_1/2Mn_1/2O₂ was synthesized by a facile sol−gel method, and the effect of calcination temperature on the structure, morphology and electrochemical performance of samples was investigated. The results show that the sample obtained at 900 °C is pure P2-type Na_2/3Fe_1/2Mn_1/2O₂ phase with good crystallization, which consists of hexagon plate-shaped particles with the size and thickness of 2−4 µm and 200−400 nm, respectively. The sample exhibits an initial specific discharge capacity of 243 mA·h/g at a current density of 26 mA/g with good cycling stability. The high specific capacity indicates that P2-type Na_2/3Fe_1/2Mn_1/2O₂ is a promising cathode material for sodium- ion batteries.     

Effects of precipitator on the morphological, structural and electrochemical characteristics of Li[Ni1/3Co1/3Mn1/3]O2 prepared via carbonate coprecipitation

Three precipitators, i.e. Na₂CO₃, (NH₄)₂CO₃ and NH₄HCO₃, are employed to prepare Li[Ni_1/3Co_1/3Mn_1/3]O₂ via the carbonate coprecipitation method. The effects of precipitator on the morphological, structural and electrochemical characteristics of the prepared samples are studied. The sample prepared by using Na₂CO₃ as precipitator has irregular particle shape and nonuniform particle size, while the sample prepared by using (NH₄)₂CO₃ as precipitator has spherical particle shape and uniform particle size. Among all the samples, the one prepared with (NH₄)₂CO₃ exhibits the best hexagonal layered structure, which results in its highest discharge capacity and best cycling performance. Therefore, precipitator plays an important role in the coprecipitation reaction and makes a great impact on the characteristics of Li[Ni_1/3Co_1/3Mn_1/3]O₂.     

Synthesis of LiNi1/3CO1/3Mn1/3O2 cathode material via oxalate precursor

Using oxalic acid and stoichiometrically mixed solution of NiCl2, CoCl2, and MnCl2 as starting materials, the triple oxalate precursor of nickel, cobalt, and manganese was synthesized by liquid-phase co-precipitation method. And then the LiNi1/3Co1/3Mn1/3O2 cathode materials for Li-ion battery were prepared from the precursor and LiOH-H2O by solid-state reaction. The precursor and LiNi1/3Co1/3Mn1/3O2 were characterized by chemical analysis, XRD, EDX, SEM and TG-DTA. The results show that the composition of precursor is Ni1/3Co1/3Mn1/3C2O4·2H2O. The product LiNi1/3Co1/3Mn1/3O2, in which nickel, cobalt and manganese are uniformly distributed, is well crystallized with a-NaFeO2 layered structure. Sintering temperature has a remarkable influence on the electrochemical performance of obtained samples. LiNi1/3Co1/3Mn1/3O2 synthesized at 900 ℃ has the best electrochemical properties. At 0.1C rate, its first specific discharge capacity is 159.7 mA·h/g in the voltage range of 2.75-4.30 V and 196.9 mA·h/g in the voltage range of 2.75-4.50 V; at 2C rate, its specific discharge capacity is 121.8 mA·h/g and still 119.7 mA·h/g after 40 cycles. The capacity retention ratio is 98.27%.     

Hydrothermal synthesis of MnCO3 nanorods and their thermal transformation into Mn2O3 and Mn3O4 nanorods with single crystalline structure

MnCO₃ nanorods with diameters of 50-150 nm and lengths of about 1-2 μm have been prepared for the first time by a facile hydrothermal method. Mn₂O₃ and Mn₃O₄ nanorods were obtained via the heat-treatment of the MnCO₃ nanorods in air and nitrogen atmosphere, respectively. The morphology and structure of the as-synthesized MnCO₃, Mn₂O₃ and Mn₃O₄ nanorods were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and selected area electron diffraction. It was found that the MnCO₃ nanorods are single-crystalline, and their morphology and single-crystalline characteristic can be sustained after thermal transformation into Mn₂O₃ and Mn₃O₄. The corresponding growth directions for MnCO₃, Mn₂O₃ and Mn₃O₄ nanorods were [2 1 4], [1 0 0] and [1 1 2], respectively. When applied as anode materials for lithium ion batteries, the Mn₂O₃ and Mn₃O₄ nanorods exhibited a reversible lithium storage capacity of 998 and 1050 mAh/g, respectively, in the first cycles.     

Effects of synthesis conditions on the structural and electrochemical properties of layered LiNi1/3Co1/3Mn1/3O2 cathode material via oxalate co-precipitation method

The uniform layered LiNi_1/3Co_1/3Mn_1/3O₂ cathode material for lithium ion batteries was prepared by using (Ni_1/3Co_1/3Mn_1/3)C₂O₄ as precursor synthesized via oxalate co-precipitation method in air. The effects of calcination temperature and time on the structure and electrochemical properties of the LiNi_1/3Co_1/3Mn_1/3O₂ were systemically studied. XRD results revealed that the optimal calcination conditions to prepare the layered LiNi_1/3Co_1/3Mn_1/3O₂ were 950°C for 15 h. Electrochemical measurement showed that the sample prepared under the such conditions has the highest initial discharge capacity of 160.8 mAh/g and the smallest irreversible capacity loss of 13.5% as well as stable cycling performance at a constant current density of 30 mA/g between 2.5 and 4.3 V versus Li at room temperature.     

Synthesis and characterization of layered Li（Ni1/3Mn1/3CO1/3）O2 cathode materials by spray-drying method

Spherical Li(Ni_(1/3)Mn_(1/3)Co_(1/3))O_2 was prepared via the homogenous precursors produced by solution spray-drying method. The precursors were sintered at different temperatures between 600 and 1 000 ℃ for 10 h. The impacts of different sintering temperatures on the structure and electrochemical performances of Li(Ni_(1/3)Mn_(1/3)Co_(1/3))O_2 were compared by means of X-ray diffractometry(XRD), scanning electron microscopy(SEM), and charge/discharge test as cathode materials for lithium ion batteries. The experimental results show that the spherical morphology of the spray-dried powers maintains during the subsequent heat treatment and the specific capacity increases with rising sintering temperature. When the sintering temperature rises up to 900 ℃ , Li(Ni_(1/3)Mn_(1/3)Co_(1/3))O_2 attains a reversible capacity of 153 mA·h/g between 3.00 and 4.35 V at 0.2C rate with excellent cyclability.     

Thermodynamics and phase diagrams in the binary systems Na2O-SiO2, Na2O-GeO2, Na2O-B2O3, Li2O-B2O3, CaO-B2O3, SrO-B2O3, and BaO-B2O3

We applied our model to the enthalpy of mixing data of the binary systems Na₂O-SiO₂, Na₂O-GeO₂, Na₂O-B₂O₃, Li₂O-B₂O₃, CaO-B₂O₃, SrO-B₂O₃, and BaO-B₂O₃. The most stable composition in the liquid, that is where the enthalpy of mixing is most negative, is with a metal-oxygen ratio of 4 to 3, for monovalent metals (Na and Li) and 3 to 4 for divalent metals (Ba and Ca) in liquid silicates or borates. The same applies to the CaO-SiO₂, CaO-Al₂O₃, PbO-B₂O₃, PbO-SiO₂, ZnO-B₂O₃, and ZnO-SiO₂ systems. The oxygen to metal ratio, its constant value in various types of systems, reflects and describes the structure of the liquid. Using the analyzed enthalpies of mixing data and the available phase diagrams, we calculated the enthalpies of formation of the various binary compounds. The results are in excellent agreement with data in the literature that were obtained from direct solid-solid calorimetry.     

Photocatalytic performance of nano-photocatalyst from TiO2 and Fe2O3 by mechanochemical synthesis

Nano-particles of homogeneous solid solution between TiO₂ and Fe₂O₃ (up to 10 mol%) have been prepared by mechanochemical milling of TiO₂ and yellow Fe₂O₃/red Fe₂O₃/precipitated Fe (OH)₃ using a planetary ball mill. Such novel solid solution cannot be prepared by conventional co-precipitation technique. A preliminary investigation of photocatalytic activity of mixed oxide (TiO₂/Fe₂O₃) on photo-oxidation of different organic dyes like Rhodamine B (RB), Methyl orange (MO), Thymol blue (TB) and Bromocresol green (BG) under visible light (300-W Xe lamp; λ > 420 nm) showed that TiO₂ having 5 mol% of Fe₂O₃ (YFT1) is 3-5 times higher photoactive than that of P25 TiO₂. The XRD result did not show the peaks assigned to the Fe components (for example Fe₂O₃, Fe₃O₄, FeO₃, and Fe metal) on the external surface of the anatase structure in the Fe₂O₃/TiO₂ attained through mechanochemical treatment. This meant that Fe components were well incorporated into the TiO₂ anatase structure. The average crystallite size and particle size of YFT1 were found to be 12 nm and 30 ± 5 nm respectively measured from XRD and TEM conforming to nanodimensions. Together with the Fe component, they absorbed wavelength of above 387 nm. The band slightly shifted to the right without tail broadness, which was the UV absorption of Fe oxide in the Fe₂O₃/TiO₂ particle attained through mechanochemical method. This meant that Fe components were well inserted into the framework of the TiO₂ anatase structure. EPR and magnetic susceptibility show that Fe³⁺ is in low spin state corresponding to μ_B = 1.8 BM. The temperature variation of μ_B shows that Fe³⁺ is well separated from each other and does not have any antiferromagnetic or ferromagnetic interaction. The evidence of Fe³⁺ in TiO₂/Fe₂O₃ alloy is also proved by a new method that is redox titration which is again support by the XPS spectrum.     

Thermodynamic optimization of the Na2O-B2O3 pseudo-binary system

The Na₂O-B₂O₃ system is thermodynamically optimized by means of the CALPHAD method. A two-sublattice ionic solution model, (Na⁺¹)_P(O⁻²,BO₃ ⁻³,B₄O₇ ⁻²,B₃O_4.5)_Q, has been used to describe the liquid phase. All the solid phases were treated as stoichiometric compounds. A set of thermodynamic parameters, which can reproduce most experimental data of both phase diagram and thermodynamic properties, was obtained. Comparisons between the calculated results and experimental data are presented.     

Surface modification of LiNi<Subscript>1/3</Subscript>Co<Subscript>1/3</Subscript>Mn<Subscript>1/3</Subscript>O<Subscript>2</Subscript> with Cr<Subscript>2</Subscript>O<Subscript>3</Subscript> for lithium ion batteries

Cr 2 O 3-coated LiNi 1/3 Co 1/3 Mn 1/3 O 2 cathode materials were synthesized by a novel method. The structure and electrochemical properties of prepared cathode materials were measured using X-ray diffraction (XRD), scanning electron microscopy (SEM), charge-discharge tests, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The measured results indicate that surface coating with 1.0 wt% Cr 2 O 3 does not affect the LiNi 1/3 Co 1/3 Mn 1/3 O 2 crystal structure (α-NaFeO 2 ) of the cathode material compared to the pristine material, the surfaces of LiNi 1/3 Co 1/3 Mn 1/3 O 2 samples are covered with Cr 2 O 3 well, and the LiNi 1/3 Co 1/3 Mn 1/3 O 2 material coated with Cr 2 O 3 has better electrochemical performance under a high cutoff voltage of 4.5 V. Moreover, at room temperature, the initial discharging capacity of LiNi 1/3 Co 1/3 Mn 1/3 O 2 material coated with 1.0 wt.% Cr 2 O 3 at 0.5C reaches 169 mAh·g 1 and the capacity retention is 83.1% after 30 cycles, while that of the bare LiNi 1/3 Co 1/3 Mn 1/3 O 2 is only 160.8 mAh·g 1 and 72.5%. Finally, the coated samples are found to display the improved electrochemical performance, which is mainly attributed to the suppression of the charge-transfer resistance at the interface between the cathode and the electrolyte.