An alkaline polymer electrochemical interface: a breakthrough in application of alkaline anion-exchange membranes in fuel cells

A novel alkaline polymer has been developed as an interfacial material for use in the preparation of metal-cation-free alkaline membrane electrode assemblies (MEAs) for all-solid-state alkaline fuel cells (AFCs) with long-term performance stability.     

Phase and Interface Engineering of Platinum–Nickel Nanowires for Efficient Electrochemical Hydrogen Evolution

The design of high‐performance electrocatalysts for the alkaline hydrogen evolution reaction (HER) is highly desirable for the development of alkaline water electrolysis. Phase‐ and interface‐engineered platinum–nickel nanowires (Pt‐Ni NWs) are highly efficient electrocatalysts for alkaline HER. The phase and interface engineering is achieved by simply annealing the pristine Pt‐Ni NWs under a controlled atmosphere. Impressively, the newly generated nanomaterials exhibit superior activity for the alkaline HER, outperforming the pristine Pt‐Ni NWs and commercial Pt/C, and also represent the best alkaline HER catalysts to date. The enhanced HER activities are attributed to the superior phase and interface structures in the engineered Pt‐Ni NWs.     

Properties of Zinc alloy electrodeposits produced from acid and alkaline electrolytes

Zinc–cobalt (Zn–Co) and zinc–nickel (Zn–Ni) alloy electrodeposits each prepared from acid and alkaline formulations were compared for their properties. Compared to alkaline baths, acid baths offer higher metal percent of the alloying element and higher current efficiency. In alkaline baths, the variation of metal percent in deposit with current density is less significant, but that of current efficiency with current density is more. Electrolyte pH does not change significantly in alkaline solutions compared to acid solutions. X-ray diffraction evaluation of Zn–Co deposits from both electrolytes indicated their presence in the η-phase, while Zn–Ni shows pure γ-phase for deposits obtained from alkaline solutions and the existence of γ-phase with traces of η-phase of zinc for deposits obtained from the acid electrolytes. Scanning electron microscope examination shows finer grain structure for deposits obtained from alkaline solutions, and atomic force microscope studies confirm their nanostructure with reduced surface roughness. Deposits obtained from the alkaline baths exhibited higher corrosion resistance probably due to their nanostructure.     

光/热成像用活性醚化物阻溶/促溶剂的分子设计

本文提供了低分子量酚类化合物与乙烯基烷基醚合成醚化率百分之百的高酸解活性醚化物(以下简称活性醚化物)的一般合成方法,并对其合成条件的优选进行了讨论.建立了原料酚类化合物与成像性能密切相关的参数,如羟当量,临界碱水不可溶羟当量,临界碱水可溶羟当量,表征原料酚类化合物阻溶、促溶能力比的M_P/A值,按照成像要求所设定的碱水易溶、碱水可溶、碱水微溶、碱水不溶(难溶)的AS_TW参数.测定或推算出活性醚化物的平均醚当量、与分子量相关的校正醚当量、活性醚化物的M_E/A_E值以及M_E/A_E值与M_P/A值的比值(即DL值)等多项参数.围绕上述参数的建立,提出了一些经验计算公式,根据所建立的参数值以及多年来从事光/热成像实验的实践,提出了光/热成像用活性醚化物分子设计的有关规则.     

炼铝用碳阳极中碱金属氧化物作用机理的量子化学研究

本文应用CNDO/2法研究了炼铝用碳阳极中添加碱金属氧化物的吸附行为, 通过优化得到了吸附的最佳模型, 考察了吸附结合能随分子间距的变化, 进而给出了碱金属氧化物在碳阳极中作用的机理。量子化学计算结果表明: 碱金属氧化物添加到炼铝用碳阳极中起传输电子的电桥作用, 是碳阳极在空气中氧化反应以及铝电解时生成氧气的氧化反应的催化剂; 理论计算和实验结果二者吻合较好, 可以用来解释若干实验结果。     

A study on the electroanalytical performance of a bismuth film-coated and Nafion-coated glassy carbon electrode in alkaline solutions

Bismuth film electrodes are widely used for determination of heavy metal ions in acidic solutions, while alkaline solutions are rarely employed. We have compared the deposition of Bi(III) and Pb(II) on a Nafion-coated glassy carbon electrode in alkaline and acidic solutions. The results indicate that both Bi(III) and Pb(II) can be deposited in either alkaline or acidic solution, but the quantity of Pb(II) deposited in alkaline solution is less than that in acidic solution. The modified electrode was used to determine heavy metal ions in both alkaline and acidic solutions, and the results of the method agree well with those of atomic absorption spectroscopy.     

Inexpensive and robust iron-based electrode substrates for water electrolysis and energy storage

The instability of iron under anodic conditions makes iron-based electrode substrates unsuitable for alkaline electrolyzers and rechargeable alkaline batteries. Therefore, significantly more expensive substrates such as nickel foam or sintered nickel are used. Nickel adds a significant cost to electrolysis and energy storage systems. We show that iron substrates can be stabilized using a unique protective thermal coating. These coatings can also yield some of the most electrocatalytically active electrodes in addition to showing no notable change in performance even after 1500 h of anodic polarization. Besides sintered iron, low-carbon steel mesh can be stabilized similarly. Low-carbon steel protected by a thin layer of lithium-doped cobalt spinel was found to be an excellent current collector for positive nickel hydroxide electrodes in alkaline batteries. Thus, surface-modified iron substrates, 40 times less expensive than nickel, are promising for lowering the material costs of alkaline water electrolyzers and rechargeable alkaline batteries.     

小功率空气冷却电感耦合等离子体发射光谱的研究 Ⅱ.碱金属和碱土金属分析特性

本文测定了碱金属、碱土金属九个元素48条谱线在空气冷却ICP中的信背比和检出限,并同全氩ICP的检出限进行了比较。本工作还测绘了各元素灵敏线与9个常见共存元素的光谱重叠扫描图,以了解可能存在的光谱干扰。     

The Role of Discrepant Reactive Intermediates on Ru-Ru2P Heterostructure for pH-Universal Hydrogen Oxidation Reaction

Developing highly efficient electrocatalysts for hydrogen oxidation reaction (HOR) under alkaline media is essential for the commercialization of alkaline exchange membrane fuel cell (AEMFC). However, the kinetics of HOR in alkaline media is complicated, resulting in orders of magnitude slower than that in acid, even for the state-of-the-art Pt/C. Here, we find that Ru-Ru₂P/C heterostructure shows HOR performance with a non-monotonous variation in a whole pH region. Unexpectedly, an inflection point located at pH≈7 is observed, showing an anomalous behavior that HOR activity under alkaline media surpasses acidic media. Combining experimental results and theoretical calculations, we propose the roles of discrepant reactive intermediates for pH-universal HOR, while H* and H₂O* adsorption strengths are responsible for acidic HOR, and OH* adsorption strength is essential for alkaline HOR. This work not only sheds light on fundamentally understanding the mechanism of HOR but also provides new designing principles for pH-targeted electrocatalysts.     

Electrocatalysis of oxygen reduction and small alcohol oxidation in alkaline media

We present here a critical review of several technologically important electrocatalytic systems operating in alkaline electrolytes. These include the oxygen reduction reaction (ORR) occurring on catalysts containing Pt, Pd, Ir, Ru, or Ag, the methanol oxidation reaction (MOR) occurring on Pt-containing catalysts, and the ethanol oxidation reaction (EOR) occurring on Ni-Co-Fe alloy catalysts. Each of these catalytic systems is relevant to alkaline fuel cell (AFC) technology, while the ORR systems are also relevant to chlor-alkali electrolysis and metal-air batteries. The use of alkaline media presents advantages both in electrocatalytic activity and in materials stability and corrosion. Therefore, prospects for the continued development of alkaline electrocatalytic systems, including alkaline fuel cells, seem very promising.     

Study on Influencing Factors of Chemical Flooding for Heavy Oil

Alkali and alkali/surfactant displacing agents are designed for two kinds of heavy oil. Results of emulsifying capacity, dynamic interfacial tension (IFT) and water-wet core flooding tests show that, although alkaline/surfactant systems exhibit better capacity in emulsification and IFT reduction, oil recovery values of alkaline/surfactant flooding are lower than those of alkaline flooding. Glass-etched micromodel tests further demonstrate that, when alkaline solution penetrates into the oil phase, water streams break into ganglia coating oil film. Water ganglia may be entrapped by narrow throats, consequently presenting a water-oil alternating slug flow. Similar water ganglia also appears in alkaline/surfactant flooding, however, water channeling along the pore surface occurs subsequently, resulting in its relatively lower oil recovery.     

苯胺在碱性溶液中的电化学聚合和聚合物的性质

苯胺在碱性溶液中电化学氧化时，阳极上形成深黄色的聚苯胺，其氧化峰电位为０．７Ｖ（ｖｓ．Ａｇ／ＡｇＣｌ含饱和ＫＣｌ溶液），比在酸性溶液中氧化约低０．３Ｖ，环一盘电极实验结果表明，在碱性溶液中，苯胺氧化时生成两种可溶性的中间物，形成的聚合物颜色不随电位和ｐＨ值而变化，在空气和碱性溶液中具有很高的稳定性，在紫外－可见光谱图上，聚合物的吸收峰出现在５００ｍ左右。     

Improvement of Sweep Efficiency by Alkaline Flooding for Heavy Oil Reservoirs

Severe viscous fingering during water flooding of heavy oil leaves a large amount of oil untouched in the reservoir. Improving sweep efficiency is vital for enhancing heavy oil recovery. This study presented a laboratory study for improving sweep efficiency by alkaline flooding in heavy oil Reservoirs. This included glass-etched micromodel flooding tests, one-dimensional flooding experiments and three-dimensional physical model study. The micromodel tests show that W/O droplet flow plays a prominent role in the alkaline flooding to improve sweep efficiency. There is a minimum alkaline concentration that generates the W/O droplet flow, and the W/O droplet flow is more obvious with the alkaline concentration increasing. A series of flood tests were conducted using 325 mPa · s, 2000 mPa · s, and 3950 mPa · s heavy oils to assess the effectiveness of W/O droplet flow in alkaline flooding for enhanced heavy oil recovery. The flood tests results demonstrate the considerable potential for improved heavy oil recovery by alkaline flooding, and moreover, the incremental oil recovery has been found to increase as the alkaline concentration increases. The result obtained in three-dimensional physical model study indicates that the sweep area can be greatly improved by the formation of W/O droplet flow in alkaline flooding.     

Bioassay of bile acids using an enzyme-linked DNA aptamer

A new analytical method for the detection of bile acids has been developed by adopting an alkaline phosphatase-linked DNA oligomer that binds to bile acids. A 5'-biotin-labeled DNA oligomer with a 40-nucleotide length that is defined by the in vitro selection method was connected with alkaline phosphatase through an avidin-biotin linkage and applied to an enzyme immunoassay format. Sample solutions were incubated with small aliquots for a cholic acid-immobilized agarose matrix, on which the alkaline phosphatase-linked DNA oligomer had been bound prior to carrying out the assay. The amount of the alkaline phosphatase-linked DNA oligomer dissociated from the cholic acid-immobilized agarose matrix, which was detected using a fluorogenic substrate for alkaline phosphatase, indicated the amount of bile acids in the samples. The results suggest that the DNA aptamer directly linked with the reporter enzyme is applicable as a detector ligand for the immunoassay format. A linear calibration range was obtained for cholic acid between 0.1 to 5 mmol l-1 with a limit of detection of 10 mumol l-1. The %RSD was 7 at 5 mmol l-1 of cholic acid.     

碱性介质中氢氧化反应电催化剂的开发:从机理认识到材料设计

阴离子交换膜(AEM)燃料电池因具有使用非贵金属作为催化剂的优点而受到广泛关注.然而,在碱性体系中,AEM燃料电池中氢氧化反应(HOR)的反应动力学比在酸性介质中的慢两个数量级.针对HOR在碱中动力学缓慢的问题,有两种主要的理论来解释,(1)pH相关的氢结合能作为主要影响因素来控制HOR动力学的理论;(2)质子和氢氧根离子的吸附共同作为影响因子来控制HOR在碱性条件下的动力学的双功能理论.本文首先讨论了在碱性电解质中可能的HOR反应机理及其Tafel性能变化.除了传统的Tafel-Volmer和Heyrovsky-Volmer-HOR机理外,还讨论了最新提出的氢氧根离子吸附参与的HOR机理来说明在酸性和碱性介质中HOR机理的差异.然后,总结了具有代表性的碱性HOR催化剂(如贵金属、合金、金属间化合物、镍基合金、碳化物、氮化物等),简要介绍了它们相应的HOR反应机理,从而进一步理解在碱性介质中不同基元反应步骤给HOR性能带来的差异.最后,提出了一种未来设计HOR碱性催化剂的可行性方案,为今后碱性环境下的HOR催化剂设计提供参考.     

碱土金属修饰Al2O3的表面热稳定性

采用浸渍法,添加不同碱土金属元素对γ-Al2O3进行改性.通过BET、XRD等手段,研究考察了在1 373 K空气中,经不同时间处理γ-Al2O3的相变和烧结情况,比较了各样品烧结后比表面积的差异.结果表明,碱土金属的引入（尤其是Sr、Ca）有效地抑制了氧化铝比表面积的损失和α相变.并对Al2O3的烧结动力学进行了研究探讨,研究表明,铝酸盐的生成并不是稳定氧化铝的根本原因,碱土金属的高温稳定作用主要是分散态的碱土金属氧化物抑制氧化铝焙烧过程中最初1 h内的烧结和α相变引起的比表面积损失.     

In silico characterization of alkaline proteases from different species of Aspergillus

A total of 49 protein sequences of alkaline proteases retrieved from GenBank representing different species of Aspergillus have been characterized for various physiochemical properties, homology search, multiple sequence alignment, motif, and super family search and phylogenetic tree construction. The sequence level homology was obtained among different groups of alkaline protease enzymes, viz alkaline serine protease, oryzin, calpain-like protease, serine protease, subtilisin-like alkaline proteases. Multiple sequence alignment of alkaline protease protein sequence of different Aspergillus species revealed a stretch of conserved region for amino acid residues from 69 to 110 and 130–204. The phylogenetic tree constructed indicated several Aspergillus species-specific clusters for alkaline proteases namely Aspergillus fumigatus, Aspergillus niger, Aspergillus oryzae, Aspergillus clavatus. The distributions of ten commonly observed motifs were analyzed among these proteases. Motif 1 with a signature amino acid sequence of 50 amino acids, i.e., ASFSNYGKVVDIFAPGQDILSCWIGSTTATNTISGTSMATPHIVGLSCYL, was uniformly observed in proteases protein sequences indicating its involvement with the structure and enzymatic function. Motif analysis of acidic proteases of Aspergillus and bacterial alkaline proteases has revealed different signature amino acid sequences. The superfamily search for these proteases revealed the presence of subtilases, serine-carboxyl proteinase, calpain large subunit, and thermolysin-like superfamilies with 45 representing the subtilases superfamily.     

Amorphous Co-P Film: an Efficient Electrocatalyst for Hydrogen Evolution Reaction in Alkaline Seawater

Seawater electrolysis is considered an attractive alternative to conventional freshwater electrolysis for hydrogen production due to the abundance of seawater in nature. For this reason, efficient electrocatalysts for hydrogen evolution reaction (HER) in alkaline seawater are highly desired. In this study, we report an amorphous Co−P alloy on nickel foam (Co−P/NF) that behaves as an efficient and stable HER electrocatalyst for alkaline seawater electrolysis. The Co−P/NF presents high catalytic performance for HER, requiring a low overpotential of 213 mV to drive a current density of 100 mA cm⁻² and a Tafel slope of 120.2 mV dec⁻¹ in alkaline seawater. Furthermore, it shows remarkable electrochemical and structural stability in alkaline seawater.     

Spectrophotometric enzyme-amplified immunoassay for thyroid stimulating hormone.

Thyroid stimulating hormone (TSH) regulates the function of the thyroid gland. Its determination at low concentrations in serum is useful in the diagnosis of hyperthyroidism. In this paper, it is detected using a spectrophotometric enzyme-amplified immunoassay. The reporter enzyme is alkaline phosphatase and its substrate is flavin adenine dinucleotide phosphate (FADP). Reaction with alkaline phosphatase converts FADP into flavin adenine dinucleotide (FAD), which, unlike FADP, re-activates apo-D-amino acid oxidase (apo-AOD). Re-activation of apo-AOD allows the product of the reporter enzyme to be amplified. The lower limit of detection for TSH by this method is 0.06 microU cm-3. This compares with 0.54 microU cm-3 for an identical assay in which p-nitrophenyl phosphate was the substrate for alkaline phosphatase. Contaminating alkaline phosphatase was removed from the reagents by affinity chromatography.     

Specific features of the bulk etching of single-crystal semiconducting silicon in aqueous KOH solutions

Bulk chemical etching of single-crystal semiconducting silicon in aqueous alkaline solutions of KOH was studied at various solution temperatures, alkaline component concentrations, and microscopic amounts of a potassium ferricyanide additive. Specific effects of these factors on the process of silicon etching are explained by comparing the corresponding activation energies. The possibility of using alkaline aqueous solutions of KOH with a potassium ferricyanide additive for fabrication of elements in microsystem technology devices is assessed.