Design of a Multilayered Oxygen-Evolution Electrode with High Catalytic Activity and Corrosion Resistance for Saline Water Splitting

The realization of seawater electrolysis requires high-performing anode materials that should possess good catalytic activity, stability, and specificity for the oxygen evolution reaction (OER) as well as high resistance toward chloride corrosion. Herein, the design of a multilayered oxygen-evolution electrode is reported to meet the multiple needs of anode material for saline water splitting. The multilayered electrode is synthesized through direct thermal boronization of commercially available NiFe alloy plate with boron powder, followed by electrochemical oxidation. And this electrode is composed of the surface oxidized NiFeBx alloy layer, the NiFeBx alloy interlayer, and the NiFe alloy substrate. The boron species are present in the form of metaborate in the outermost oxidized NiFeBx layer, and their existence is conductive to the generation and stabilization of the catalytic active phase γ-(Ni,Fe)OOH. The introduction of NiFeBx interlayer effectively prevents the excessive oxidative corrosion of the anode material in the electrolyte containing chloride ions.     

A zirconium-free glaze system for sanitary ceramics with SiO2-CaCO3-TiO2 composite opacifier containing anatase: Effect of interface combination among SiO2, CaCO3 and TiO2

TiO₂ is an ideal substitute to ZrSiO₄ ceramic opacifier, yet it is limited to application because of the undesirable yellowing resulting from rutile formation. Herein, the SiO₂-CaCO₃-TiO₂ composite opacifier (Si-Ca-Ti) was constructed. The glaze used Si-Ca-Ti presents a superior opacification performance than ZrSiO₄ opacified glaze without causing yellowing, showing L*, a*, b* values of 94.81, -0.67 and 3.23. By comparison, the glaze using SiO₂, CaCO₃, and TiO₂ mixture shows lower opacification and yellowish surface with L* and b* values of 92.99 and 5.36. It is revealed that there is a close interface bonding among SiO₂, CaCO₃ and TiO₂ in Si-Ca-Ti, which promotes their combination reaction to generate opacification phase titanite and inhibit rutile formation when sintering, resulting in the white surface and opacification improvement of the glaze. This study proposes a green and efficient strategy to achieve white and highly opacified glaze for sanitary ceramics, exhibiting good application prospect.     

生物基异己糖醇聚酯的制备及其构效关系研究进展

异己糖醇是一类碳水化合物衍生二元醇,具有高刚性、手性、亲水性和低毒等特性,在制备新型生物基、生物可降解高分子材料方面具有广阔的发展前景。围绕近年来研究较为充分的全脂肪型及半芳香型异己糖醇基均聚酯与共聚酯,综述了其合成、热学性能、力学性能、生物降解性能及潜在应用,探讨此类聚酯的高效聚合反应工艺及构效关系。异己糖醇结构单元的引入可有效提高聚合物的玻璃化转变温度,以及促进其水解和生物降解性能,在构建具有更高性能的环境友好型聚酯方面具有较高潜力,有望应用于工程塑料、纤维、生物医药等领域。此类生物基聚酯的大规模商业化需进一步开发更高效、温和的聚合反应工艺以攻克其热敏感和热降解问题。     

Crystal structure and functional properties of Nd1.6Ca0.4Ni1-yCuyO4+δ as prospective cathode materials for intermediate temperature solid oxide fuel cells

Complex oxides Nd_1.6Ca_0.4Ni_1-yCu_yO_4+δ (y = 0.0–0.4) have been prepared by a pyrolysis of glycerol-nitrate compositions. According to the X-ray diffraction analysis, the materials are single-phase up to y = 0.3 and crystallize in an orthorhombic structure (Bmab) at room temperature. High-temperature studies assert that they all undergo a phase transition from orthorhombic to tetragonal (I4/mmm) structure in a range of 300–400 °C. With Cu doping, the over-stoichiometric oxygen content δ decreases from 0.07 (y = 0.0) down to 0.00 (y = 0.3). The studies on the compact samples reveal the maximum value of total conductivity (165 S cm^?1 at 420 °C) and the minimum value of the linear coefficient of thermal expansion (11.9·10^?6 K^?1 in a range of 400–1000 °C in air) at y = 0.2. Chemical compatibility of the Nd_1.6Cа_0.4Ni_1-yCu_yO_4+δ (y = 0.0, 0.2) oxides with oxygen- and proton conducting electrolytes (Ce_0.9Gd_0.1O_1.95, Ce_0.8Sm_0.2O_1.9 and BaCe_0.5Zr_0.3Y_0.1Yb_0.1O_3-δ) up to a temperature of 1100 °C is demonstrated.     

Heat transfer enhancement of concentrated solar absorber using hollow cylindrical fins filled with phase change material

A concentrated solar absorber with finned phase change materials was experimentally studied using a Scheffler type parabolic dish concentrator. The absorber's inner surface was fixed with hollow cylindrical containers filled with phase change material (PCM) for heat transfer augmentation. The absorber's selected PCM was acetanilide (Melting point of 116 °C)—the cylindrical capsules protruding into the fluid side to create turbulence and mixing and acting as fins. The absorber surface temperature was observed to be about 130–150 °C during the outdoor tests while passing fluid through the absorber. The fluid flow rate varied from 60 to 100 kg/h during the outdoor experiments. The peak energy and exergy efficiency of parabolic dish collector (PDC) at the fluid flow rate of 80 kg/h with PCM integrated solar absorber was found to be about 67.88% and 6.96%, respectively. The integration of cylindrical PCM containers resulted in more heat transfer augmentation in the solar absorbers. The optimized solar absorber could be suitable for various applications like steam generation, biomass gasification, space heating, and hydrogen generation.     

Cobalt loaded organic acid modified kaolin clay for the enhanced catalytic activity of hydrogen release via hydrolysis of sodium borohydride

Inorganic acids such as hydrochloric acid (HCl), nitric acid (HNO₃) and sulphuric acid (H₂SO₄) are generally used in the acid modification of clays. Here, CoB catalyst was synthesized on the acetic acid-activated kaolin support material (CH₃COOH -kaolin- CoB) with an alternative approach. This prepared catalyst, firstly, was used to catalyze the hydrolysis of NaBH₄ (NaBH₄-HR). The structure of the raw kaolin, kaolin-CH₃COOH, and CH₃COOH-kaolin-CoB samples were characterized by X-ray diffraction spectroscopy (XRD), Fourier transforms infrared spectroscopy (FTIR), scanning electron microscope (SEM), and nitrogen adsorption. At the same time, this catalyst performance was examined by Co loading, NaBH₄ concentration, NaOH concentration, temperature and reusability parameters. The end times of this hydrolysis reaction using raw kaolin-CoB and CH₃COOH-kaolin-CoB were found to be approximately 140 and 245 min, respectively. The maximum hydrogen generation rates (HGRs) obtained at temperatures 30 °C and 50 °C were 1533 and 3400 mL/min/g_catalyst, respectively. At the same time, the activation energy was found to be 49.41 kJ/mol.     

Hydrodistillation condition adjustment for different material particle sizes: a method to increase batch‐to‐batch quality consistency

Varying material particle sizes represent a common contributing factor to the batch‐to‐batch variation of extraction yields. To increase the batch‐to‐batch quality consistency of extracts, a method was proposed to adjust the extraction conditions for different material particle sizes, taking the hydrodistillation extraction process of Radix Curcumae and Fructus Gardeniae as a case study. Statistical models were built for five sesquiterpenes including curcumenone, curcumenol, curdione, curzerenone and furanodienone, to quantitatively describe the effects of particle size and process parameters on their extraction yields. An increase in sodium chloride concentration remarkably increased the yields of curcumenone and curcumenol, and a larger solvent‐to‐solid ratio increased the yields of five sesquiterpenes. Under the adjusted process parameters for two different particle sizes, the yield for each compound was controlled to fall in the 90–110% target range. The proposed method can be applied to various extraction processes of foods and herbal medicines.     

镍钴锰酸锂正极材料 LiNi1/3Mn1/3Co1/3O2的制备方法和研究进展

LiNi1/3Co1/3Mn1/3O2很好的构成了LiNiO2/LiCoO2/LiMnO2三类材料的固溶体系，兼容了三种材料的优点且弥补了上述材料作为正极材料的不足，是备受欢迎的锂电池正极材料。详细叙述了该正极材料的结构特征和电化学反应特征及近几年国内外对111型镍钴锰酸锂正极材料的研究进展，介绍了固相法，共沉淀法和溶胶凝胶法等方法的原理和特点，并阐述了掺杂和包覆改性对正极材料电化学性能的影响。     

考虑速度滑移的多孔质静压气体轴承静特性

对于多孔质材料内的气体流动,基于Darcy定律建立其理论模型,并建立气膜间隙流场的雷诺方程,考虑速度滑移修正方程;将上述2个区域的压力分布方程进行耦合,通过有限元方法对耦合后的压力分布方程进行离散化,用超松弛迭代求解出气膜内各节点的压力分布,分析速度滑移对多孔质静压气体轴承静特性的影响。结果表明,考虑速度滑移所计算的气膜压力分布变化平稳过渡,没有较大的突变。计算轴承的承载力及刚度,结果显示在气密间隙小于15μm时,随着气膜厚度的增大偏心导致的压差增大使承载力不断增大;且当速度滑移系数小于0.1时,速度滑移对轴承承载力及刚度有较大的影响。