Bubbles pinned on electrodes: Friends or foes of aqueous electrochemistry?

Electrochemists and engineers regard adherent gas bubbles as redox-inactive and therefore blocking entities. Adhesion of bubbles at electrodes generally carries an energy penalty. But this is not always the case: bubbles pinned on an electrode surface initiate the oxidation of water-soluble species under conditions where such reactions would normally be considered impossible. Here we critically review the recent literature that is beginning to unveil the novel concept of on-water electrochemistry. Harnessing electrochemical reactivity of the water–gas–electrode interface has the potential to become a game-changer in organic electrosynthesis, accelerating the transition toward a sustainable chemical industry by simplifying the direct integration of renewable electricity into the production of commodity chemicals.     

纳米气泡电化学研究进展

纳米气泡广泛存在于许多自然现象和工业生产过程,其自身具有独特的物理化学性质.由于涉及气体反应的纳米电催化及能源转化技术的迅速发展,有关纳米气泡的电化学研究越来越受研究者的关注.针对电极界面纳米气泡的研究不仅有助于实现对气泡行为的调控,指导催化剂电极界面的合理设计以提高电催化效率,也可以从科学上去了解纳米催化剂本征电催化...     

Optical-facilitated single-entity electrochemistry

Single-entity electrochemistry focusing on the study of transient electrochemical process at the confined interface, has become a promising field that addresses questions from multi-disciplines such as cellular biology, material chemistry, organic chemistry, etc. It offers the fruitful information hidden in bulk electrochemical measurements. As the optical techniques improve in spatial and temporal resolution, the combination of electrochemistry with optical microspectroscopy provides more comprehensive information of single-entity electrochemistry. Herein, we review recent progress made in optical–electrochemical measurements covering three aspects from the precise localization and temperature measurements of single compartments, to the in-situ tracking of dynamic behaviors of single nanoparticles in electrochemical process, and to the monitoring confinement-controlled electrochemistry at the single molecule/ion level. The review demonstrates how these optical methods are innovatively integrated with single-entity sensing. It also reveals how these optical–electrochemical combinations push single-entity electrochemistry forward.     

Electrochemistry and electroanalytical applications of carbon nanotubes: a review.

This review addresses recent developments in electrochemistry and electroanalytical chemistry of carbon nanotubes (CNTs). CNTs have been proved to possess unique electronic, chemical and structural features that make them very attractive for electrochemical studies and electrochemical applications. For example, the structural and electronic properties of the CNTs endow them with distinct electrocatalytic activities and capabilities for facilitating direct electrochemistry of proteins and enzymes from other kinds of carbon materials. These striking electrochemical properties of the CNTs pave the way to CNT-based bioelectrochemistry and to bioelectronic nanodevices, such as electrochemical sensors and biosensors. The electrochemistry and bioelectrochemistry of the CNTs are summarized and discussed, along with some common methods for CNT electrode preparation and some recent advances in the rational functionalization of the CNTs for electroanalytical applications.     

CFD-PBM approach for the gas-liquid flow in a nanobubble generator with honeycomb structure

In recent years, nanobubble technologies have drawn great attention due to their wide applications in many fields of science and technology. From previous studies, a kind of honeycomb structure for high efficiency nanobubble generation has been proposed. In this paper, the numerical simulations of bubbly flow in the honeycomb structure were performed by using a computational fluid dynamics–population balance model (CFD-PBM) coupled model. The numerical model was based on the Eulerian multiphase model and the population balance model (PBM) was used to calculate the bubble size distribution. The bubble size distributions in the honeycomb structure under different work conditions were predicted. Two different drag force models (Schiller-Naumann model and Tomiyama model) and two different aggregation models (Luo model and turbulent aggregation model) were investigated. Both two drag models gave similar prediction of bubble number density distribution at the outlet. The results obtained from Luo model had better reflection of the trend of number density distribution. The turbulence dissipation rate ε can be used to evaluate the nanobubble generating ability. The water tank was not included in the CFD model in this work. The bubbles in the water tank should be studied in the future.     

Bubble Solution Description by Non-Extensive Thermodynamics: Pressure Effect

We showed in this study that nanobubble solutions should not be considered as the simple juxtaposition of autonomous phases (a solution and bubbles) but as particular entities, that is, “supersaturated solutions” where gas is simultaneously in two forms in permanent exchange. Gibbs′ extensive thermodynamics cannot claim to describe legitimately their behavior. In this work, we showed how the use of the non-extensive thermodynamics allows describing the physicochemical properties of such media, some of which are counter-intuitive. Thus, an increase in pressure can result in an increase in the bubble size, contrary to what is provided by Boyle-Mariotte's law. The theoretical relationships proposed in this work constitute another approach to bubble solutions, which considers the non-autonomous nature of the components of supersaturated gas solutions and their “non-extensive” nature.     

Synthesis and Molecular Structure of Bis-Ferrocene-Containing Acyl Thiourea Derivatives

Ferrocene is a compound with excellent stability. In addition, it has very favourable electrochemical properties. So the synthesis, structure, electrochemistry and coordination behaviors of ferrocene-derivatives have attracted considerable attention in recent years.[1,2] Electrondonating atoms such as N, S, O in the derivatives are known for their coordination particularly with transition metals. [3] Two new bis-ferrocene-containing acyl thiourea derivatives are synthesized. The derivatives are confirmed by IR spectrum, 1H NMR and elemental analysis. These compoundshave many electrondonating atoms and two ferrocenes. The structure of one compound is shown below. The study onelectrochemistry and coordination behaviors is in the progress.     

Concentration of hydrogen nanobubbles in electrolyzed water

The hydrogen concentration of solutions supersaturated with hydrogen comprising dissolved hydrogen and hydrogen bubbles obtained through water electrolysis was studied. The rate of decrease in concentration of hydrogen nanobubble diameter below 600 nm and dissolved hydrogen with elapsed time after electrolysis was seemed to be independent of ionic strength and ion type and storage temperature. The concentration of hydrogen nanobubbles (mol dm(-3)) in electrolyzed water decreases with ionic strength, while the total hydrogen concentration remains roughly constant. The hydrogen nanobubble concentration increases in accordance with the nature of ions existing in solution in the following order I- < Br- < Cl- and K+ < Li+ < Na+. It is shown that the ratio of hydrogen nanobubble concentration to total hydrogen concentration of hydrogen in a catholyte strongly depends on the ratio in the supersaturated hydrogen solution near the electrode surface.     

Synthesis and electrochemical applications of gold nanoparticles

This review covers recent advances in synthesis and electrochemical applications of gold nanoparticles (AuNPs). Described approaches include the synthesis of AuNPs via designing and choosing new protecting ligands; and applications in electrochemistry of AuNPs including AuNPs-based bioelectrochemical sensors, such as direct electrochemistry of redox-proteins, genosensors and immunosensors, and AuNPs as enhancing platform for electrocatalysis and electrochemical sensors.     

《碳纳米材料电化学》专辑序言 ——方兴未艾的电化学能量转换和存储先进材料和技术

可以预见,在相当一段时期内,能源和环境将是全球发展的两大主题. 其实,人类对能源的获取方式将对地球的生态环境和人类未来的生存状态和生活方式产生重要影响. 正因为如此,世界各国正在大力发展可再生能源和清洁能源. 电化学能源是将化学能高效转变为电能的一种能量转换方式,它历史悠久,但不断被改进和创新,尤其是近年来得到了较快的发展. 目前,电化学能源转换和存储器件主要包括一次电池（如锌锰电池等）、二次电池（如铅酸电池、镍氢电池、锂离子电池等）、燃料电池、金属-空气电池以及超级电容器等. 电化学能源和其它可再生能源相互补充、交叉利用将是未来清洁能源的主要发展方向.     

Electrochemistry in flames: a preliminary communication

We propose that the ionised gaseous media of a flame may be a suitable medium in which electrochemical phenomena can be investigated. This communication contains preliminary investigations into electrochemical phenomena in the gas phase, by considering the media of a flame as an electrolyte. A hypothesis is presented which possibly explains the occurrence of an electrochemical potential established at a metallic electrode surface when inserted into the flame. Using cyclic voltammetry with a three-electrode system, we observe current steps, which we have interpreted as Faradaic reduction of iron and copper ions introduced into the flame. Although the interpretations presented here are at this stage speculative, the results open new avenues for research and applications of electrochemistry by proposing ionised gaseous media as vehicles for gas phase electrochemistry.     

Progress in electrochemistry of hybrid diamond/sp2-C nanostructures

Hybrid diamond/sp²-C nanostructures have aroused growing interests in electrochemistry currently owing to the good chemical/physical properties, including high electrical conductivity, mechanical robustness, and high specific surface area, as well as the unique electrochemical properties, namely, an enhanced electrochemical activity while retaining a wide potential window and low background currents when properly engineering the microstructure. This mini-review presents the recent electrochemistry process of diamond/sp²-C nanostructures. In particular, the synthetic methods, microstructures, and possible growth mechanism of diamond/sp²-C nanostructures are briefly summarized. Then, the electrochemical property tailoring is addressed in detail, and subsequently, their potential applications in electrochemistry including electrochemical sensors, supercapacitors, electrocatalysis, and other applications are discussed. The future perspectives of diamond/sp²-C nanostructures in electrochemistry finally conclude this review.     

The potentials of additive manufacturing for mass production of electrochemical energy systems

Additive manufacturing has established itself as a popular and powerful tool in electrochemistry research and development. In this short review, we focus on the latest results in both 3D printing and electrochemistry communities that could potentially benefit manufacturing in the electrochemical industry. We provide insights from recent and relevant research works and conclude that the likely scenario in the industry is the deployment of a combination of subtractive and additive technologies in order to manufacture high quality and cost-effective electrochemical reactors within reasonable timeframes.     

Charge transport in confined concentrated solutions: A minireview

This Minireview summarizes several recent experiments clouding over prevailing theoretical understanding of charge transport behaviors in electrochemical systems; they are nonlinear concentration dependence of ionic conductivity, ultra-long Debye length in ionic liquids, nonmonotonic double layer charging behavior, and anomalous increase in area specific capacitance with decreasing nanopore size. Theoretical activities reveal that nanoconfinement and high concentration exert strong influence on charge distribution and transport via strong ion-ion correlations and ion-wall interactions. By exemplifying where and why classical theories of charge transport fail, we defy the popular point of view that theoretical electrochemistry is well-established and we are left with applications of these theories only.     

Thermodynamic stability of interfacial gaseous states

We studied the thermodynamic stability of interfacial gaseous states on atomically smooth highly ordered pyrolytic graphite (HOPG) in water using atomic force microscopy. Quasi-two-dimensional gas layers (micropancakes) required a higher supersaturation of gas than spherical-cap-shaped nanobubbles. The two forms of gas coexisted at a sufficiently high supersaturation of gas where one or more of the nanobubbles may sit on top of a micropancake. The micropancakes spontaneously coalesced with each other over time. After the coalescence of two neighboring micropancakes which each had had a nanobubble on top, one nanobubble grew at the expense of the other. We analyzed these results assuming temporal and local quasi-equilibrium conditions.     

Investigating the Existence of Bulk Nanobubbles with Ultrasound

Nanobubbles are expected to dissolve in milliseconds. Experimental evidence of nanobubbles that were stable for days had thus been first received with circumspection. If the large number of experimental confirmations has now made clear that surface nanobubbles could exist, bulk nanobubbles are still subject to debate. When observations are reported, the main problem is to make sure the observed particles are really made of gas. We show that ultrasound is an ideal tool for investigating the existence of bulk nanobubbles: 1) it is sensitive to minute quantities of gas, 2) it allows one to determine the bubble size distribution, 3) it discriminates unambiguously between gaseous and solid/liquid inclusions. To illustrate the efficiency of ultrasonic detection, we performed size measurements of bubbles produced by a commercial nano‐/microbubble generator. No nanobubble was detected with this device. It would be insightful to use ultrasonic detection in experimental situations for which stable nanobubbles were reported.     

Mesoporous cobalt oxide for largely improved lithium storage properties

We report the microstructure,application for lithium-ion batteries of mesoporous Co3O4 prepared by modified KIT-6 template method.The sample was characterized by XRD,TEM,HRTEM and nitrogen adsorption.Their electrochemical behaviors as electrode reactants for lithium ion batteries were evaluated by cyclic voltammograms and static charge-discharge.A direct comparison of electrochemical behaviors between mesoporous nanostructure and bulk reflects interesting "nanostructure effect",which is reasonably discussed in terms of how the 3D nanostructures of Co3O4 materials function in tuning their electrochemistry.The results demonstrate that further improvement of electrochemical performance in transition metal-oxide-based anode materials can be realized via the design of multiporous nanostructured materials.     

蛋白质直接电化学研究及其应用

蛋白质直接电化学研究在生物电化学中具有重要地位,对于蛋白质结构．功能研究、蛋白质电子传递过程的热力学和动力学研究都有着重要意义,而且是研制第三代电化学生物传感器的基础。本文对在裸电极、分子自组装修饰电极和模拟生物膜修饰电极上进行蛋白质直接电化学的研究及相关应用进行简要综述。     

Recent advances in nanocollision electrochemistry

Ensemble averaging measurements obscure the link between the electrochemical performance and the specific properties of an individual because of the interplay of inhomogeneity and heterogeneity. Nanocollision electrochemistry has attracted increasing interest because of its extremely high sensitivity, revealing the intrinsic properties of individual entities that are masked in the traditional ensemble measurements. In this perspective review, we summarized the recent developments in nanocollision-based single entity electrochemistry and photoelectrochemistry, the combined nanocollision electrochemistry with the other complementary techniques, as well as accurate data process. In closing, future challenges, opportunities, and destinations related to nanocollison electrochemistry were discussed.     

蛋白质直接电化学研究及其应用

蛋白质直接电化学研究在生物电化学中具有重要地位,对于蛋白质结构-功能研究、蛋白质电子传递过程的热力学和动力学研究都有着重要意义,而且是研制第三代电化学生物传感器的基础。本文对在裸电极、分子自组装修饰电极和模拟生物膜修饰电极上进行蛋白质直接电化学的研究及相关应用进行简要综述。