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Nanoscale electrochemical movies and synchronous topographical mapping of electrocatalytic materials
Faraday Discussions ( IF 3.4 ) Pub Date : 2018-03-22 , DOI: 10.1039/c8fd00028j
Cameron L. Bentley 1, 2, 3, 4 , Patrick R. Unwin 1, 2, 3, 4
Affiliation  

Techniques in the scanning electrochemical probe microscopy (SEPM) family have shown great promise for resolving nanoscale structure–function (e.g., catalytic activity) at complex (electro)chemical interfaces, which is a long-term aspiration in (electro)materials science. In this work, we explore how a simple meniscus imaging probe, based on an easily-fabricated, single-channeled nanopipette (inner diameter ≈ 30 nm) can be deployed in the scanning electrochemical cell microscopy (SECCM) platform as a fast, versatile and robust method for the direct, synchronous electrochemical/topographical imaging of electrocatalytic materials at the nanoscale. Topographical and voltammetric data are acquired synchronously at a spatial resolution of 50 nm to construct maps that resolve particular surface features on the sub-10 nm scale and create electrochemical activity movies composed of hundreds of potential-resolved images on the minutes timescale. Using the hydrogen evolution reaction (HER) at molybdenite (MoS2) as an exemplar system, the experimental parameters critical to achieving a robust scanning protocol (e.g., approach voltage, reference potential calibration) with high resolution (e.g., hopping distance) and optimal scan times (e.g., voltammetric scan rate, approach rate etc.) are considered and discussed. Furthermore, sub-nanoentity reactivity mapping is demonstrated with glassy carbon (GC) supported single-crystalline {111}-oriented two-dimensional Au nanocrystals (AuNCs), which exhibit uniform catalytic activity at the single-entity and sub-single entity level. The approach outlined herein signposts a future in (electro)materials science in which the activity of electroactive nanomaterials can be viewed directly and related to structure through electrochemical movies, revealing active sites unambiguously.

中文翻译:

纳米级电化学膜和电催化材料的同步形貌图

扫描电化学探针显微镜(SEPM)系列技术已显示出解决纳米级结构-功能的巨大希望(例如(催化活性)在复杂的(电)化学界面,这是(电)材料科学领域的长期愿望。在这项工作中,我们探索如何基于简单易制的单通道纳米移液器(内径≈30 nm)构造一个简单的弯月成像探头,以快速,通用且快速地将其部署在扫描电化学细胞显微镜(SECCM)平台中。直接,同步地在纳米尺度上对电催化材料进行电化学/拓扑成像的可靠方法。以50 nm的空间分辨率同步获取地形和伏安数据,以构建可解析10 nm以下尺度的特定表面特征的地图,并在几分钟的时间尺度上创建由数百个电位分辨图像组成的电化学活性影片。2)作为示例系统,实验参数对于实现具有高分辨率(例如,跳跃距离)和最佳扫描时间(例如,伏安扫描速率,接近速率)的鲁棒扫描协议(例如,接近电压,参考电势校准)至关重要)进行了讨论。此外,用玻璃碳(GC)支撑的单晶{111}取向二维Au纳米晶体(AuNCs)表现出亚纳米级反应性作图,该单晶在单实体和亚单实体水平上均表现出均匀的催化活性。本文概述的方法标志着(电子)材料科学的未来,其中可以直接查看电活性纳米材料的活性并通过电化学电影将其与结构相关,从而明确揭示活性位点。
更新日期:2018-10-10
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