Electrochemistry

电化学
  • 文章类型: Journal Article
    本文探讨了脉冲模式下电化学氧化的好处,利用潜力,电流,和功率脉冲。虽然以前已经研究了电位和电流脉冲电化学技术用于废水处理,到目前为止,还没有研究包括功率脉冲。这项工作的目的是通过将这种脉冲类型应用于探针分子的电化学氧化来突出功率脉冲的优点,甲草胺.为了这个目标,研究了操作参数的影响和不同脉冲模式的比较,并将其与甲草胺在连续模式下电化学氧化获得的结果进行了比较。研究表明,使用功率脉冲电化学氧化可获得最佳结果,180分钟后100%甲草胺降解,240分钟后矿化率为38.3%。这些结果优于文献中报道的使用铂电极的连续电流输入处理的结果。这项新技术可能是处理污染水和减少淡水储备压力的有效方法。
    This article explores the benefits of electrochemical oxidation in pulsed mode, using potential, current, and power pulses. While potential and current pulse electrochemical technology has been previously studied for wastewater treatment, no study has included power pulses until now. The objective of this work is to highlight the advantages of power pulses by applying this pulse type to the electrochemical oxidation of a probe molecule, alachlor. For this aim, the influence of operating parameters and the comparison of the different pulse modes were investigated and compared to the results obtained with the electrochemical oxidation of alachlor in continuous mode. The study shows that the best results were obtained with the power pulse electrochemical oxidation with 100% alachlor degradation after 180 min and a mineralisation yield of 38.3% after 240 min. These results were better than those reported in the literature for treatments with continuous current input using platinum electrodes. This new technique could be an effective and efficient way to treat contaminated water and reduce the pressure on freshwater reserves.
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  • 文章类型: Journal Article
    开发锂离子和钠离子电池的新材料是材料科学的重中之重。这种发展总是包括性能测试和科学研究。同步辐射技术提供了研究电池的独特能力。电化学电池设计应针对同步加速器研究进行优化,而不会损失电化学性能。这种设计也应与操作测量兼容,这是研究电池的最合适方法,并提供最可靠的结果。细胞可以调整的实验设置越多,实验越容易,越快,结果越可靠。这需要优化窗户材料和尺寸,细胞拓扑,电极等上的压力分布.达到更高的测量效率,而不会失去电化学循环中的稳定性和可重复性。这里,我们提出了一种针对核磁共振技术优化的细胞设计,使用核前向散射进行测试,同步加速器穆斯堡尔源和核非弹性散射。
    Developing new materials for Li-ion and Na-ion batteries is a high priority in materials science. Such development always includes performance tests and scientific research. Synchrotron radiation techniques provide unique abilities to study batteries. Electrochemical cell design should be optimized for synchrotron studies without losing electrochemical performance. Such design should also be compatible with operando measurement, which is the most appropriate approach to study batteries and provides the most reliable results. The more experimental setups a cell can be adjusted for, the easier and faster the experiments are to carry out and the more reliable the results will be. This requires optimization of window materials and sizes, cell topology, pressure distribution on electrodes etc. to reach a higher efficiency of measurement without losing stability and reproducibility in electrochemical cycling. Here, we present a cell design optimized for nuclear resonance techniques, tested using nuclear forward scattering, synchrotron Mössbauer source and nuclear inelastic scattering.
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  • 文章类型: Journal Article
    能够连续监测指示健康状况的生理参数的可穿戴感测平台的出现已经导致临床医学的范式转变。这种便携式的可访问性和适应性,不显眼的设备可以实现主动,基于实时生理见解的个性化护理。虽然可穿戴传感平台展示了持续监测生理参数的强大功能,器件制造通常需要专门的设施和技术专长,限制部署机会和创新潜力。最近出现的传感器制造的快速原型方法,如激光诱导石墨烯(LIG),提供了通过低成本规避这些障碍的途径,可扩展的制造。然而,激光加工的固有限制将基于LIG的柔性电子设备的空间分辨率限制为最小激光光斑尺寸。对于CO2激光器-通常报道的用于设备生产的激光器-这对应于〜120μm的特征尺寸。这里,我们展示了一个简单的,低成本模板掩模技术,以减少最小可分辨特征尺寸的LIG基于设备的120±20μm到45±3μm时,由CO2激光制造。器件性能的表征揭示了这种模版掩蔽的LIG(s-LIG)方法在电性能方面产生了伴随的改善,我们假设这是图案化LIG宏观结构变化的结果。我们通过生产包括温度和多电极电化学传感器的普通传感器来展示这种制造方法的性能。我们制造通常无法通过天然CO2激光加工实现的细线微阵列电极,展示了扩展设计能力的潜力。将具有和不具有模板的微阵列传感器与传统的宏LIG电极进行比较揭示了s-LIG传感器对于类似的电活性表面区域具有显著降低的电容。除了提高传感器性能,这种金属模板技术可以提高分辨率,从而扩展了在低资源环境下可扩展制造高性能可穿戴传感器的能力,而无需依赖传统的制造途径。
    The advent of wearable sensing platforms capable of continuously monitoring physiological parameters indicative of health status have resulted in a paradigm shift for clinical medicine. The accessibility and adaptability of such portable, unobtrusive devices enables proactive, personalized care based on real-time physiological insights. While wearable sensing platforms exhibit powerful capabilities for continuously monitoring physiological parameters, device fabrication often requires specialized facilities and technical expertise, restricting deployment opportunities and innovation potential. The recent emergence of rapid prototyping approaches to sensor fabrication, such as laser-induced graphene (LIG), provides a pathway for circumventing these barriers through low-cost, scalable fabrication. However, inherent limitations in laser processing restrict the spatial resolution of LIG-based flexible electronic devices to the minimum laser spot size. For a CO2 laser-a commonly reported laser for device production-this corresponds to a feature size of ∼120 μm. Here, we demonstrate a facile, low-cost stencil-masking technique to reduce the minimum resolvable feature size of a LIG-based device from 120 ± 20 μm to 45 ± 3 μm when fabricated by CO2 laser. Characterization of device performance reveals this stencil-masked LIG (s-LIG) method yields a concomitant improvement in electrical properties, which we hypothesize is the result of changes in macrostructure of the patterned LIG. We showcase the performance of this fabrication method via production of common sensors including temperature and multi-electrode electrochemical sensors. We fabricate fine-line microarray electrodes not typically achievable via native CO2 laser processing, demonstrating the potential of the expanded design capabilities. Comparing microarray sensors made with and without the stencil to traditional macro LIG electrodes reveals the s-LIG sensors have significantly reduced capacitance for similar electroactive surface areas. Beyond improving sensor performance, the increased resolution enabled by this metal stencil technique expands capabilities for scalable fabrication of high-performance wearable sensors in low-resource settings without reliance on traditional fabrication pathways.
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  • 文章类型: Journal Article
    对锂离子电池成本的担忧引起了人们对LiFePO4(LFP)和LiMn1-xFexPO4(LMFP)阴极的极大兴趣。将Mn包含在橄榄石结构中会导致Fe和Mn的原子分布不均匀,导致可逆容量降低并阻碍其实际应用。在这里,通过共沉淀反应,提出了LMFP与Nb和Mg的共掺杂,然后进行喷雾干燥过程和煅烧。发现与同价Nb掺杂形成的LiNbO3主要位于表面,而等价Mg2+掺杂发生在颗粒的主体中。与共掺杂的LMFP阴极和石墨阳极组装的全电池表现出优异的循环稳定性和比容量,同时保持良好的振实密度,与未掺杂或单掺杂(仅具有Nb或Mg)相比。共掺杂的样品在C/2速率下在300个循环内表现出99%的容量保留。优越的性能源于Nb涂层促进的增强的离子/电子传输以及大量Mg掺杂导致的增强的Mn2/3氧化还原动力学。总之,这项工作揭示了不同掺杂剂在增强LMFP容量和循环稳定性方面的协同作用的重要性。
    The concerns on the cost of lithium-ion batteries have created enormous interest on LiFePO4 (LFP) and LiMn1-xFexPO4 (LMFP) cathodes However, the inclusion of Mn into the olivine structure causes a non-uniform atomic distribution of Fe and Mn, resulting in a lowering of reversible capacity and hindering their practical application. Herein, a co-doping of LMFP with Nb and Mg is presented through a co-precipitation reaction, followed by a spray-drying process and calcination. It is found that LiNbO3 formed with the aliovalent Nb doping resides mainly on the surface, while the isovalent Mg2+ doping occurs into the bulk of the particle. Full cells assembled with the co-doped LMFP cathode and graphite anode demonstrate superior cycling stability and specific capacity, while maintaining good tap density, compared to the undoped or mono-doped (only with Nb or Mg). The co-doped sample exhibits a capacity retention of 99% over 300 cycles at a C/2 rate. The superior performance stems from the enhanced ionic/electronic transport facilitated by Nb coating and the enhanced Mn2+/3+ redox kinetics resulting from bulk Mg doping. Altogether, this work reveals the importance of the synergistic effect of different dopants in enhancing the capacity and cycle stability of LMFP.
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  • 文章类型: Journal Article
    多价离子电池作为传统锂离子电池的有希望的替代品,由于其较高的电荷密度和可持续储能解决方案的潜力,已经引起了极大的关注。然而,多价离子的缓慢扩散是多价离子电池电极材料的主要问题。在这次审查中,探索了MXene基材料在多价离子电池应用中的适用性,聚焦洋葱,如镁(Mg2+),铝(Al3+),锌(Zn2+),和超越。MXene的独特结构提供了大的层间间距和丰富的表面官能团,有利于有效的离子嵌入和扩散,使其成为具有优异的比容量和功率密度的多价离子电池电极的优异候选物。总结和讨论了MXene合成和增强其电化学性能的工程技术的最新进展。MXenes的多功能性及其利用多种多价离子的能力,这篇评论强调了基于MXene的材料在彻底改变多价离子电池领域方面的广阔前景。
    Multivalent-ion batteries have garnered significant attention as promising alternatives to traditional lithium-ion batteries due to their higher charge density and potential for sustainable energy storage solutions. Nevertheless, the slow diffusion of multivalent ions is the primary issue with electrode materials for multivalent-ion batteries. In this review, the suitability of MXene-based materials for multivalent-ion batteries applications is explored, focusing onions such as magnesium (Mg2+), aluminum (Al3+), zinc (Zn2+), and beyond. The unique structure of MXene offers large interlayer spacing and abundant surface functional groups that facilitates efficient ion intercalation and diffusion, making it an excellent candidate for multivalent-ion batteries electrodes with excellent specific capacity and power density. The latest advancements in MXene synthesis and engineering techniques to enhance its electrochemical performance have been summarized and discussed. With the versatility of MXenes and their ability to harness diverse multivalent ions, this review underscores the promising future of MXene-based materials in revolutionizing the landscape of multivalent-ion batteries.
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  • 文章类型: Journal Article
    磺化的三(1-苯基吡唑)铱(III)配合物([Ir(sppz)3]3-)用作广泛使用的三(2,2'-联吡啶)钌(II)([Ru(bpy)3]2)与三正丙胺(TPrA)共反应物的ECL检测系统的概念证明非发射增强剂,通过TPrA氧化的电催化和发光体的有效化学激发作用。使用自干扰ECL光谱,我们表明,增强剂从电极表面扩展了所需的电生成前体的扩散。先前报道的通过这些途径的增强已被增强子的固有ECL混淆,但是使用[Ir(sppz)3]3-获得了[Ru(bpy)3]2ECL强度的增加,而没有伴随发射。最显著的增强(11倍)发生在与“间接”共反应物ECL途径相关的低电位下,当发光体固定在微珠上作为增强的ECL测定的一般模型时,其转化为2至6倍的增强。
    A sulfonated tris(1-phenylpyrazolato)iridium(III) complex ([Ir(sppz)3]3-) serves as a proof-of-concept non-emissive enhancer of the widely used ECL detection system of tris(2,2\'-bipyridine)ruthenium(II) ([Ru(bpy)3]2+) with tri-n-propylamine (TPrA) co-reactant, acting through electrocatalysis of TPrA oxidation and efficient chemi-excitation of the luminophore. Using self-interference ECL spectroscopy, we show that the enhancer extends diffusion of the required electrogenerated precursors from the electrode surface. Previously reported enhancement through these pathways has been confounded by the inherent ECL of the enhancer, but the increase in [Ru(bpy)3]2+ ECL intensity using [Ir(sppz)3]3- was obtained without its concomitant emission. The most prominent enhancement (11-fold) occurred at low potentials associated with the \'indirect\' co-reactant ECL pathway, which translated to between 2- and 6-fold enhancement when the luminophore was immobilised on microbeads as a general model for enhanced ECL assays.
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  • 文章类型: Journal Article
    工作台稳定的底物的电化学或光化学单电子氧化可以产生自由基阳离子,其作为各种键形成过程中的中间体提供独特的反应性。这样的中间体可以潜在地参与自由基和离子键的形成;然而,所涉及的机制很复杂,尚未完全理解。在这里,我们报道了酸性条件下的电化学自由基阳离子氮杂-Wacker环化反应,预计将通过烯烃的单电子氧化产生的自由基阳离子进行。
    Electrochemical or photochemical single-electron oxidation of bench-stable substrates can generate radical cations that offer unique reactivities as intermediates in various bond-formation processes. Such intermediates can potentially take part in both radical and ionic bond formation; however, the mechanisms involved are complicated and not fully understood. Herein, we report electrochemical radical cation aza-Wacker cyclizations under acidic conditions, which are expected to proceed via radical cations generated by single-electron oxidation of alkenes.
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  • 文章类型: Journal Article
    由于其独特的层结构,2D材料已被证明是用于可再充电电池的有前途的电极材料。然而,单个2D材料不能满足能量密度的所有性能要求,功率密度,和循环寿命。构建基于2D材料的异质结构提供了协同处理单个2D材料的缺陷并调节物理和电化学性质的机会。增加的层间距离和增加的结合能与异质结构的离子可以促进电荷转移,提高电化学反应性,导致可充电电池性能增强。在这里,我们总结了由2D材料组成的异质结构的最新发展及其在可充电电池中的应用。首先,系统地介绍了基于二维材料的异质结构的不同制备策略和优化结构工程策略。其次,分别讨论了基于二维材料的异质结构在可充电电池中的独特功能。最后,提出了挑战和观点,以激发基于2D材料的异质结构的未来研究。
    Because of their unique layer structure, 2D materials have demonstrated to be promising electrode materials for rechargeable batteries. However, individual 2D materials cannot meet all the performance requirements of energy density, power density, and cycle life. Constructing 2D materials-based heterostructures offers an opportunity to synergistically handle the deficiencies of individual 2D materials and modulate the physical and electrochemical properties. The enlarged interlayer distance and increased binding energy with ions of heterostructures can facilitate charge transfer, boost electrochemical reactivities, resulting in an enhanced performance in rechargeable batteries. Here we summarize the latest development of heterostructures consisted of 2D materials and their applications in rechargeable batteries. Firstly, different preparation strategies and optimized structure engineering strategies of 2D materials-based heterostructures are systematically introduced. Secondly, the unique functions of 2D materials-based heterostructures in rechargeable batteries are discussed respectively. Finally, challenges and perspectives are presented to inspire the future study of 2D materials-based heterostructures.
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  • 文章类型: Journal Article
    在当代社会,开发可靠的即时护理(POC)生物传感器以及时发现癌症标志物至关重要。在各种传感器类型中,基于丝网印刷电极(SPE)的传感器,特别是电化学的,成为POC应用的有希望的候选人。尽管正在努力创建许多基于SPE的传感器,不断追求提高他们的灵敏度和分析能力。这项研究提出了一种先进的电化学传感器,旨在灵敏地检测唾液中的肝细胞癌(HCC)标志物甲胎蛋白(AFP)。该传感器采用羟基磷灰石修饰的金SPE,TiO2纳米颗粒,1-丁基-3-甲基咪唑双(三氟甲基磺酰基)酰亚胺离子液体(IL),和AFP单克隆抗体。在使用循环伏安法(CV)和差分脉冲伏安法(DPV)进行彻底表征和优化后,生物传感器具有广泛的检测范围(0.01-400ng/mL),低检测限(LOD)为0.058ng/mL,并显示出高选择性,重复性,再现性,和稳定性。此外,当用加标的人类唾液样本测试时,生物传感器表现出优异的恢复性和鲁棒性,展示其非侵入性和POC诊断HCC的潜力。在环保意识评估中,使用AGREE指标评估生物传感器的绿色度,得了0.85分的高分。该分数表明生物传感器与绿色分析化学原理的一致性,强调其环保属性。这种创新的电化学传感器有助于持续努力的高效和可靠的POC诊断工具,并与开发环保解决方案的更广泛承诺保持一致。
    In contemporary society, developing dependable point-of-care (POC) biosensors for the timely detection of cancer markers is crucial. Among various sensor types, screen-printed electrode (SPE)-based sensors, particularly electrochemical ones, stand out as promising candidates for POC applications. Despite ongoing efforts to create numerous SPE-based sensors, there is a continuous pursuit to enhance their sensitivity and analytical capabilities. This study presents an advanced electrochemical sensor designed to sensitively detect the hepatocellular carcinoma (HCC) marker Alpha-fetoprotein (AFP) in saliva. The sensor employs a gold SPE modified with hydroxyapatite, TiO2 nanoparticles, 1-butyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)imide ionic liquid (IL), and AFP monoclonal antibodies. After thorough characterization and optimization using cyclic voltammetry (CV) and differential pulse voltammetry (DPV), the biosensor exhibited a broad detection range (0.01-400 ng/mL), a low limit of detection (LOD) at 0.058 ng/mL, and demonstrated high selectivity, repeatability, reproducibility, and stability. Furthermore, when tested with spiked human saliva samples, the biosensor displayed excellent recovery and robustness, showcasing its potential for noninvasive and POC diagnosis of HCC. In an environmentally conscious evaluation, the biosensor\'s greenness was assessed using the AGREE metric, yielding a high score of 0.85. This score indicates the biosensor\'s alignment with the principles of green analytical chemistry, underlining its eco-friendly attributes. This innovative electrochemical sensor contributes to the ongoing efforts for efficient and reliable POC diagnostic tools and aligns with a broader commitment to developing environmentally friendly solutions.
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  • 文章类型: Journal Article
    所提出的研究旨在评估一种新型卟啉类家族代表的外周协调特性,该家族代表之前是为了潜在的传感目的而合成的。采用两种合成途径获得马来腈衍生物,进一步用作环四聚化反应中的起始材料。在第一个,DAMN用于与2-噻吩-甲醛和硼氢化钠的连续双还原烷基化。在第二个,在5-乙基-2-甲基吡啶硼烷络合物的存在下,在甲醇和乙酸中,将DAMN与2-噻吩-甲醛进行一锅反应。按照Linstead的方法,环化反应导致具有甲基(2-噻吩基亚甲基)取代基的新型对称镁(II)八氨基卟啉。通过循环和差分脉冲伏安法评估了大环的电化学性质,揭示了一个还原和两个氧化峰电位。另外的光谱电化学测量显示在0.6V的施加电势下形成阳离子形式的大环。使用滴定结合UV-vis光谱法测量由于新型卟啉的钯离子引起的配位性质。Pd2的滴定表明,四氮杂卟啉在0.1至5钯摩尔当量范围内具有良好的传感活性。此外,Pd2+离子配位也通过电化学研究进行了评估,表明在金属阳离子存在下0.1V的峰电位偏移。DFT计算表明,在UV-vis和1HNMR研究中,理论数据与实验数据之间具有良好的一致性。
    The presented studies aimed to evaluate the peripheral coordinating properties of a novel porphyrinoid family representative preceded by its synthesis for potential sensing purposes. Two synthetic pathways were employed to a obtain maleonitrile derivative, further used as a starting material in the cyclotetramerization reaction. In the first one, DAMN was used in sequential double-reductive alkylation with 2-thiophene-carboxyaldehyde and sodium borohydride. In the second, DAMN was used in a one-pot reaction with 2-thiophene-carboxyaldehyde in the presence of a 5-ethyl-2-methylpyridine borane complex in methanol and acetic acid. Following the Linstead approach, the cyclization reaction led to a novel symmetrical magnesium(II) octaaminoporphyrazine with methyl(2-thiophenylmethylene) substituents. The macrocycle\'s electrochemical properties were assessed by cyclic and differential pulse voltammetries revealing one reduction and two oxidation peak potentials. The additional spectroelectrochemical measurements showed formation of a cationic form of the macrocycle at an applied potential of 0.6 V. The coordinating properties due to the palladium ion of novel porphyrazines were measured with the use of titration combined with UV-vis spectrometry. The titration of Pd2+ revealed the good sensing activity of porphyrazine in the range of 0.1 to 5 palladium molar equivalents. In addition, Pd2+ ions coordination was also assessed by electrochemical studies, indicating the peak potential shift of 0.1 V in the presence of metal cations. DFT calculations showed the good agreement between theoretical and experimental data in the UV-vis and 1H NMR studies.
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