Lithium Intercalation Compound Dramatically Influences the Electrochemical Properties of Exfoliated MoS2

MoS₂ and other transition metal dichalcogenides (TMDs) have recently gained a renewed interest due to the interesting electronic, catalytic, and mechanical properties which they possess when down‐sized to single or few layer sheets. Exfoliation of the bulk multilayer structure can be achieved by a preliminary chemical Li intercalation followed by the exfoliation due to the reaction of Li with water. Organolithium compounds are generally adopted for the Li intercalation with n‐butyllithium (n‐Bu‐Li) being the most common. Here, the use of three different organolithium compounds are investigated and compared, i.e., methyllithium (Me‐Li), n‐butyllithium (n‐Bu‐Li) and tert‐butyllithium (t‐Bu‐Li), used for the exfoliation of bulk MoS₂. Scanning transmission electron microscopy (STEM), Raman spectroscopy, X‐ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV) are adopted for a comprehensive characterization of all materials under investigation. In addition, catalytic properties towards the hydrogen evolution reaction (HER) and capacitive properties are also tested. Different organolithium compounds exhibit different extent of Li intercalation resulting in different degrees of exfoliation. The inherent electrochemical behavior of MoS₂ consisting of significant anodic and cathodic peaks as well as its capacitive behavior and catalytic properties towards hydrogen evolution reaction are strongly connected to the exfoliation compound used. This research significantly contributes to the development of large‐scale synthesis of electrocatalytic MoS₂‐based materials.     

Myoglobin/gold nanoparticles/carbon spheres 3-D architecture for the fabrication of a novel biosensor

A novel biosensor based on a myoglobin/gold nanoparticles/carbon spheres (Mb-AuNPs-CNs) 3-D architecture bioconjunction has been fabricated for the determination of hydrogen peroxide (H₂O₂). Cyclic voltammetry (CV), Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM) were used to characterize the bioconjunction of the AuNPs-CNs with Mb. Experimental results demonstrate that the AuNPs-CNs hybrid material is more effective in facilitating electron transfer of the immobilized enzyme than CNs alone, which can be attributed to the unique nanostructure and larger surface area of the bioconjunction. The biosensor displayed good performance for the detection of H₂O₂ with a wide linear range from 0.28 μmol/L to 116.5 μmol/L and a detection limit of 0.12 μmol/L. The Michaelis-Menten constant K _M^app value was estimated to be 0.3 mmol/L. The resulting biosensor exhibited fast amperometric response, and good stability, reproducibility, and selectivity to H₂O₂. This article is published with open access at Springerlink.com     

钨铜化合物氢还原制备钨铜复合粉研究

通过对钨铜化合物氢还原过程进行热力学分析,找到了制备均匀细颗粒钨铜复合粉的热力学途径--彻底快速除去还原系统中的水分.设计了封闭还原系统,用此系统进行氢气热还原,不仅使氢气得到充分利用,而且容易判断反应终点.通过系统内的特殊装置除水,降低了还原温度,在600℃下还原得到了混合均匀的钨铜复合粉.系统能彻底快速除去反应生成的水分,使反应物的湿度大大降低,确保得到细颗粒的钨铜复合粉,其平均粒径小于80nm.     

枪黑色Sn-Ni合金在NaOH溶液中的析氢电催化性能

为了降低电解制氢的电耗,提高经济效益.作者对枪黑色Sn-Ni合金在NaOH溶液中的析氢电流化性能进行了研究.试验测出的电化学参数表明,在NaOH溶液中电解制氢时,枪黑色Sn-Ni合金的析氢电催化性能比45钢和高硫镍的强很多,而且具有很高的电化学稳定性.用它取代目前工业上使用的45钢和高硫镍作为电解制氢的阴极,可显著降低制氢的生产成本.     

地下煤制气制取液化天然气和液氢工艺研究

目的脱除地下煤制气中的酸气,将地下煤制气中的CH₄和H₂分离出来并液化。 方法对常见的分离方法进行对比,确定采用低温精馏法对煤制气进行脱酸气、分离CH₄和H₂并液化。根据低温精馏法的原理,设计了一种全新的地下煤制气脱酸气、分离CH₄和H₂并液化的工艺流程,该工艺主要由两个精馏塔、一个两相分离器和三级氦膨胀制冷系统组成。同时利用HYSYS软件对其进行模拟分析,确定最优参数。 结果该工艺可以将地下煤制气中CO₂的摩尔分数脱除到0,H₂S的摩尔分数脱除到3.65×10-14,满足处理要求。同时可以实现CH₄回收率为99.97%,加压液化天然气(PLNG)的摩尔分数为99.97%,H₂的回收率为98.30%,液氢(LH₂)的摩尔分数为99.99%。 结论该工艺可以有效利用地下煤制气制取PLNG和LH₂,且所需能耗较传统工艺能耗降低了11.64％,具有较高的经济效益。      

Zn对AB5型贮氢合金的影响

研究了Zn替代Co对AB5型MlNi3.6Mn0.4Al0.3Co0.7贮氢合金相结构和电化学性能的影响。Zn替代Co使合金的晶胞参数和体积增大,导致贮氢合金最大放电容量增加,循环稳定性有所下降;随着Zn含量由0增加到0.5,氢的扩散系数由0.31×10-7m2/s增加到3.72×10-7m2/s,交换电流密度由157 mA/g增加到191 mA/g,合金极化电阻由1.23Ω减少到1.01Ω,合金表面电催化活性和高倍率性能得到了改善。     

制氢工艺改造的节能效果

介绍甲醇裂解制氢工艺特性,比较电解制氢和甲醇裂解制氢不同生产工艺电能消耗,分析节电机理,计算削峰能力,评价经济效果,为制氢生产企业提供典例。     

可再生能源发电制绿氢和氢能储运技术现状与发展分析

氢能已纳入我国能源发展战略。绿氢作为一种绿色二次能源,能够助推实现“双碳”目标。氢气制备和储运是氢能产业链的关键环节。重点阐述了电解水制绿氢和氢能储运的技术类型与发展现状,并对其应用前景和发展趋势进行了分析;提出氢气生产成本和储运方式是限制氢大规模部署的主要技术瓶颈;最后为传统电力企业进入绿氢制备和储运产业提供了一些思考和建议。     

Strong Hydrogen Bonds in Acetylenedicarboxylic Acid Dihydrate

Acetylenedicarboxylic acid dihydrate (ADAD) represents a complex with strong hydrogen bonding between the carboxylic OH and the water molecule. An X-ray re-examination of the ADAD crystal structure confirms the O^…O distance of the short hydrogen bonds, and clearly shows different bond lengths between the two oxygen atoms with respect to the carbon atom in the carboxyl group, indicating a neutral structure for the complex. The neutral structure was also confirmed by vibrational spectroscopy, as no proton transfer was observed. The diffraction studies also revealed two polymorph modifications: room temperature (α) and low temperature (β), with a phase transition at approximately 4.9 °C. The calculated vibrational spectra are in satisfactory agreement with the experimental spectra. A comparison of the structure and the vibrational spectra between the ADAD and the oxalic acid dihydrate reveals some interesting details. The crystal structures of both crystal hydrates are almost identical; only the O^…O distances of the strongest hydrogen bonds differ by 0.08 Å. Although it was expected that a larger O^…O spacing in the ADAD crystal may significantly change the infrared and Raman spectra, especially for the frequency and the shape of the acidic OH stretching vibration, both the shape and frequency are almost identical, with all subpeaks topped on the broad OH stretching vibration. The O^…O distance dependent are only in- and out-of-plane OH deformations modes. The presence of polarons due to the ionized defects was not observed in the vibrational spectra of ADAD. Therefore, the origin of the broad OH band shape was explained in a similar way to the acid dimers. The anharmonicity of a potential enhances the coupling of the OH stretching with the low-frequency hydrogen bond stretching, which, in addition to the Fermi resonance, structures the band shape of the OH stretching. The fine structure found as a superposition of a broad OH stretching is attributed to Davydov coupling.     

ALPUR除气装置在25 t熔铸生产线中的应用

25 t燃油熔铝炉熔炼的铝合金熔体中氢含量较高,配备ALPUR除气净化装置,通过合理使用,达到了满意的除氢效果,保证了铸锭的内部质量。