扫描电化学显微镜在光电化学研究中的应用

深入研究各种光电化学反应过程的机理和反应动力学性质等对提升光电转换效率、发展绿色高效光伏能源器件具有重要意义.扫描电化学显微镜(SECM)是一种具有高时空分辨率的电化学扫描探针显微镜技术,不仅可以研究光电催化反应的机理和动力学性质,还可以通过光电流反馈模式进行组合成像,实现光电催化剂的性能评估和优选,近年来逐渐成为光电化学研究领域微区观测和反应动力学研究的重要技术手段.本综述系统介绍了SECM在光电化学研究中的应用,首先介绍用于光电化学研究的SECM的实验装置、工作原理和工作模式,然后对SECM在光合作用、光诱导电荷转移、电致化学发光、光解水、太阳能电池等光电化学研究领域的应用进行了详细介绍,最后展望了SECM在光电化学研究领域中的应用发展方向.     

扫描电化学微探针的发展及其在局部腐蚀研究中的应用

简要概述当前国内外具有空间分辨能力的扫描微探针技术及其在腐蚀研究中的应用,包括扫描微电极技术(SMET)、扫描电化学显微镜(SECM)、原子力显微镜(AFM)、扫描Kelvin探针技术(SKP)等,其中SMET、SECM、SKP及局部交流阻抗技术可直接测定腐蚀电极表面或界面电化学不均一性的分布图像,而原子力显微镜技术则是通过分子间作用力从纳米尺寸测量腐蚀过程表面形貌的变化.文中侧重介绍作者近年先后建立的具有微米空间分辨度的电化学微探针技术,并利用各种扫描探针技术研究金属/溶液界面电化学不均一性及其局部腐蚀过程.研究表明,空间分辨电化学方法的发展及应用,加深了人们对金属表面和金属/溶液界面电化学不均一性,特别是金属局部腐蚀发生、发展及过程机理的认识.     

扫描电化学显微镜在生物医学领域的应用研究进展

研究病变细胞和组织的异常表现可为理解重大疾病发生发展的病理机理和新型药物筛选提供重要参考.扫描电化学显微镜(Scanning electrochemical microscopy,SECM)是一种基于电化学原理的扫描探针显微镜,通过记录探针在样品表面扫描时的电流或电位等信息,对活细胞的形态和多种化学信息进行原位、实时、精准表征.近10年来,SECM在重大疾病相关的细胞、细胞球和微组织层次的应用研究得到快速发展.本文从与疾病相关的SECM研究角度入手,分别从单细胞、细胞球和微组织层次小结SECM近10年来在生物医学领域的应用研究进展.首先介绍SECM的仪器组成、探针种类和工作模式,其次分别介绍SECM在神经细胞、心肌细胞和肿瘤细胞的应用进展,之后介绍SECM近期在细胞球和微组织的最新应用,最后提出并展望SECM技术在生物医学领域进一步应用所面临的挑战和发展方向.     

扫描电化学显微镜在光电能源研究领域的应用

作为一种扫描探针技术,扫描电化学显微镜(SECM)在金属防腐、材料表征、生物医学和新能源技术等领域的研究中扮演着重要角色。本文简要介绍了SECM的基本工作原理和常用的两种工作模式:反馈模式和收集/产生模式;综述了SECM在太阳能电池和太阳光解水制氢两个光电能源研究领域的应用进展,同时结合课题组的工作基础,特别是近期利用SECM筛选合适金属离子掺杂改性WO₃光阳极的工作,对SECM在筛选半导体电极材料方面的应用特点进行了实例展示介绍,最后简要总结了SECM在光电能源研究领域的发展及方向。     

扫描电化学显微镜及其在界面电化学研究中的应用

对扫描电化学显微镜(Scanning Electrochemical Microscope，SECM)的发展及其在界面电化学中的研究应用进行了评述。介绍了SECM的工作原理以及常用的操作模式，并对SECM在液／液界面、固／液界面等方面的应用进行了总结。     

扫描电化学显微镜在电催化氧反应研究中的应用

本综述首先简单介绍了扫描电化学显微镜的基本概况,尤其是不同的工作模式. 其次,有针对性地介绍了SECM的不同工作模式在氧还原和水解析氧反应相关研究中的应用. 最后,对扫描电化学显微镜未来在新能源转换存储系统研究领域的应用进行了展望.     

金属纳米电极的制备、表征及其在电化学测量中的应用

本文简要介绍了各种金属纳米电极的制备及表征方法。结合我们自己的工作,重点介绍了纳米电极在电化学反应动力学参数测量及扫描电化学显微镜(SECM)中的应用,并对其发展前景进行了展望。引用文献78篇。     

扫描电化学显微镜原位表征pH值对核电蒸汽发生器合金腐蚀行为的影响(英文)

用扫描电化学显微镜(SECM)和电化学阻抗谱(EIS)原位表征了溶液pH值对核电蒸汽发生器800合金溶液中的腐蚀行为的影响.实验结果表明:在酸性氯化钠溶液中,SECM探针渐进曲线为正反馈,表明800合金为活化阳极溶解,腐蚀电位下的EIS图呈现完整的单容抗弧特征;而在中性或者碱性溶液中,SECM探针渐进曲线为负反馈,表明800合金为自钝化,不同阳极电位下的EIS图均呈现不完整的容抗弧特征,但随着阳极极化电位的增加,EIS谱容抗弧半径减小,表明钝化膜的耐蚀性下降;SECM二维扫描图像结果显示探针电流增加,表明电极表面活性增加,即钝化膜的溶解速度增加.而在中性或者碱性溶液中的SECM二维图像中均可观察到若干活性点,这可能与晶界或者金属夹杂物等有关.     

扫描电化学显微镜原位表征pH值对核电蒸汽发生器合金腐蚀行为的影响

用扫描电化学显微镜(SECM)和电化学阻抗谱(EIS)原位表征了溶液pH值对核电蒸汽发生器800 合金溶液中的腐蚀行为的影响. 实验结果表明：在酸性氯化钠溶液中,SECM探针渐进曲线为正反馈,表明800合金为活化阳极溶解,腐蚀电位下的EIS 图呈现完整的单容抗弧特征;而在中性或者碱性溶液中,SECM探针渐进曲线为负反馈,表明800 合金为自钝化,不同阳极电位下的EIS 图均呈现不完整的容抗弧特征,但随着阳极极化电位的增加,EIS 谱容抗弧半径减小,表明钝化膜的耐蚀性下降;SECM二维扫描图像结果显示探针电流增加,表明电极表面活性增加,即钝化膜的溶解速度增加. 而在中性或者碱性溶液中的SECM二维图像中均可观察到若干活性点,这可能与晶界或者金属夹杂物等有关.     

扫描电化学显微镜及其在生物分析中的应用研究进展

扫描电化学显微镜(SECM)以其极高的空间分辨率、操作简单、测试样品更接近实际应用情况等特点,近年来逐渐成为生物样品分析中的重要工具,在研究细胞形貌、氧化还原活性、细胞膜上活性位以及跨细胞膜的物质传递方面具有优异的性能。本文介绍了扫描电化学显微镜的工作原理及其在细胞分析、酶分析、DNA分析、抗体抗原分析及微修饰等方面的应用,并展望了该技术未来的发展方向。     

有机涂层／金属界面腐蚀的微区电化学

以扫描开尔文探针，局部交流阻抗和扫描电化学显微镜为代表的微区电化学技术以其高精度、高空间解析度的定域分析优势被广泛应用。本文简要介绍了这三种技术的测量原理和关键问题，并着重归纳了这些技术应用于有机涂层／金属界面腐蚀行为的研究成果，包括界面微区表观形貌的获取，不同界面腐蚀机制的推理验证及其影响因素的作用机理等，并对三种技...     

Analysis of corrosion processes at the surface of diamond-like carbon protected zinc selenide waveguides

A detailed surface analytical study on the corrosion behavior of unprotected and diamond-like carbon (DLC)-coated mid-infrared (MIR) waveguides used in remote sensing applications at strongly oxidizing conditions is presented. High-quality DLC films, with a thickness of 100 nm serving as MIR-transparent corrosion barrier, have been produced at the surface of zinc selenide (ZnSe) attenuated total reflection waveguides via pulsed laser deposition techniques. IR microscopy and atomic force microscopy are applied to investigate the chemical inertness of DLC-based membranes against aqueous solutions of hydrogen peroxide. These stability studies show that uncoated ZnSe waveguides are subject to severe chemical surface modifications, while DLC-protected waveguides maintain their optical properties and chemical integrity. In situ studies on the corrosion behavior by a recently developed approach combining scanning electrochemical microscopy (SECM) with Au/Hg amalgam ultramicroelectrodes in a scanning stripping voltammetry experiment provides additional insight into the mechanisms of the corrosion process. It is demonstrated that the combination of surface analytical techniques and, in particular, the innovative application of SECM with amalgam electrodes provides superior information on corrosion processes at the surface of optical waveguides. This detailed study confirms the efficiency of protective DLC coatings deposited onto IR-transparent optical waveguides, rendering this novel concept ideal for sensing applications in harsh environments.     

In-situ Study the Corrosion Degradation Mechanism of Tinplate in Salty Water by Scanning Electrochemical Microscopy

In this work, the corrosion degradation of tinplate in contact with salty water is investigated by scanning electrochemical microscopy (SECM) electrochemical impedance spectroscopy (EIS). Experimental results indicate tin maintains at passive state during the exposure; however, pores and defects existed in tin coating leads to an exposure of carbon steel substrate to the electrolyte, in which localized corrosion tends to occur within the pore. A phenomenological model is proposed to interpret corrosion mechanism of tinplate in contact with salty food based on the proposed electrochemical equivalent circuit.     

SECM study of the pH distribution over Cu samples treated with 2-mercaptobenzothiazole in NaCl solution

This paper reports the effect of treatment with 2-mercaptobenzothiazole (2MBT) (a corrosion inhibitor) on pH distribution over Cu samples monitored in situ using scanning electrochemical microscopy (SECM) in potentiometric mode. Line scans were conducted over two copper wires embedded in insulating resin, one of which had been pre-treated with 2MBT. It was found that the treated Cu sample had a less acidic character than the non-treated sample. Furthermore, the pH above the resin areas is considerably more acidic than that above either Cu wire. This feature is attributed to the consumption of OH⁻ ions on the non-treated Cu wire during the formation of atacamite as a corrosion product, and the tautomeric equilibrium established by the detached 2-mercaptobenzothiazole molecules in the bulk electrolyte. These pH distributions are spatially resolved in the SECM mapping above both Cu wires.     

In situ scanning electrochemical microscopy (SECM) detection of metal dissolution during zinc corrosion by means of mercury sphere-cap microelectrode tips

This work presents a scanning electrochemical microscopy (SECM)-based in situ corrosion probing methodology that is capable of monitoring the release of zinc species in corrosion processes. It is based on the use of Hg-coated Pt microelectrodes as SECM tips, which offer a wider negative potential range than bare platinum or other noble-metal tips. This allows for the reduction of zinc ions at the tip to be investigated with low interference from hydrogen evolution and oxygen reduction from aqueous solutions. The processes involved in the corrosion of zinc during its immersion in chloride-containing solutions were successfully monitored by scanning the SECM tip, set at an adequate potential, across the sample either in one direction or in the X-Y plane parallel to its surface. In this way, it was possible to detect the anodic and cathodic sites at which the dissolution of zinc and the reduction of oxygen occurred, respectively. Additionally, cyclic voltammetry (CV) or constant potential measurements were used to monitor the release of zinc species collected at the tip during an SECM scan.     

Review: Recent applications of scanning electrochemical microscopy to the study of charge transfer kinetics

Scanning electrochemical microscopy (SECM) has been proven to be a valuable technique for the quantitative investigation and surface analysis of a wide range of processes that occur at interfaces. In particular, there is a great deal of interest in studying the kinetics of charge transfer characteristics at the solid/liquid and liquid/liquid interface. This overview outlines recent advances and applications of SECM to the investigation of charge transfer reactions at the solid/liquid interface and liquid/liquid interface.     

Fabrication of microbial chip using collagen gel microstructure

A microbial chip was fabricated by filling the micropores on a glass substrate with collagen-embedded Escherichia coli(E. coli) cells, and characterized by scanning electrochemical microscopy (SECM) in a solution containing ferricyanide. The activity of the E. coli cells in the collagen gel microstructure was imaged and characterized with SECM by mapping the localized concentration of ferrocyanide produced by the respiration of the cells. The SECM-based activity measurement detected as low as approximately 100 E. coli cells. Furthermore, the optical-microscopic observation indicated that the E. coli cells on the chip proliferated during the incubation. The sequential SECM measurements were performed for the same E. coli chip to obtain the microbial growth curve for a small number of microorganisms.     

Constant-distance mode AC-SECM for the visualisation of corrosion pits

The local visualisation of corrosion pits has so far failed to convincingly prove the advantage of scanning microscopy in overcoming Abbey’s Limit. Thus, for imaging pit initiation and instant pit growth the resolution of the methods used for detecting the related changes in local electrochemical activity has to be significantly improved. Progress into this direction has been achieved by combining shear force based constant-distance mode scanning electrochemical microscopy (SECM) with the alternating current mode of this technique (AC-SECM). A very small corrosion pit was generated by inducing active corrosion underneath an accurately positioned 5 μm diameter Pt disk SECM tip that served as counter electrode in the direct mode of SECM. Before and after pit initiation, constant-distance mode AC-SECM images were recorded and subsequently used to identify the area of broken passivity. The results demonstrate the feasibility of the suggested approach to image actively corroding sites with overall dimensions of only a few micrometers. Combination of constant-distance scanning with AC-SECM is an important prerequisite for further improving spatial resolution by employing smaller-diameter micro- or even nano-electrodes as SECM tips.     

Visualization and characterization of electroactive defects in the native oxide film on aluminium

Spatial!y localized electrochemical activity at Al/Al2O3 electrodes has been investigated using scanning electrochemical microscopy (SECM) in order to establish the relationship between localized corrosion of Al (and Al alloys) with the defect structure of the native Al2O3 film. Local electron transfer at microscopic defects (2 to 50 microm radius) was visualized in acetonitrile solutions using the nitrobenzene/nitrobenzene radical anion (Eo approximately -1.6 V vs. Ag/Ag+) and tetracyanoquinodimethane/tetracyanoquinodimethane radical anion couples (Eo approximately -0.3 V) as redox mediators for imaging. SECM investigations revealed no significant differences in electrochemical activity at Al/AI203 electrodes in the two mediator solutions, indicating that electrical conduction at the defect sites is weakly dependent on interfacial potential and the electric field across the Al2O3 film. The density of electroactive defects observed by SECM varied by 2 to 3 orders of magnitude between electrodes prepared from the same source of Al (either 99.450% and 99.9995%) suggesting that electrical conduction in the native oxide is very sensitive to surface preparation. Defect densities as low as approximately 3 sites cm(-2) were readily measured by SECM.