Interfacial Electrochemistry and Electrocatalysis: Understanding and Directing Electrochemical Phenomena at the Molecular Level

我们在电化学和电催化的研究包括三个创新的推力，将同时追求获得电化学现象的分子水平的理解，发现材料的新特性，并开发电化学过程的新理论。我们将合成形状和尺寸可控的Pd纳米颗粒（Pd-NPs），并使用材料科学方法（透射电子显微镜，TEM，X射线衍射，XRD，电子断层扫描，ET）表征其结构和组成。将使用电化学技术（循环伏安法，CV，计时电流法，CA和计时库仑法，CC）检查它们的H吸收能力。吸收的H的量将与Pd-NP的尺寸和形状相关，以确定定义其吸收能力的参数。将制备吸收等温线以检查过程的热力学和材料科学技术以分析H进入时Pd-NP的结构。我们将通过研究氧还原和析出反应（ORR，OER）的机理和动力学来研究电催化中的组成-尺寸-结构-反应性现象。我们将合成Pt，PtNi和PtCo纳米颗粒和单晶，并将其用作ORR和OER的催化剂。将使用电化学技术（塔菲尔图、极化曲线、CV和CA）评价其活性。电化学和分析技术（电感耦合等离子体质谱法，ICPMS）将用于检查这些材料的降解。将使用TEM、XRD、ET、扫描电子显微镜（SEM）和能量色散X射线光谱（EDS）分析电化学测量前后电极材料的结构和组成。结果的比较将揭示组成-尺寸-结构-反应性现象和性质。伴随界面电化学过程的质量变化知之甚少，需要在很宽的温度范围内进行检查。我们将开发和应用变温电化学石英晶体纳米天平（VT-EQCN）来研究界面电化学过程，如催化剂的氧化和降解。该技术将揭示T依赖的结构形成和结构破坏过程。该研究计划为突破和发现创造了机会。这是一个雄心勃勃的挑战，但我训练有素的HQP能够成功地承担困难的项目。虽然这项研究本质上是基础性的，但它将通过创造新知识而使电化学技术受益。最后，作为该项目的一部分，HQP培训将获得电化学和电催化方面的知识，并将发展一套独特的跨学科技能，这将提高他们未来的职业生涯。

Our research in electrochemistry and electrocatalysis consists of three innovative thrusts that will be concurrently pursued to gain molecular-level understanding of electrochemical phenomena, discover new properties of materials, and develop new theories of electrochemical processes. We will synthesize Pd nanoparticles (Pd-NPs) of controlled shape and size, and characterize their structures and compositions using materials science methods (transmission electron microscopy, TEM, X-ray diffraction, XRD, electron tomography, ET). Their H absorbing capacity will be examined using electrochemical techniques (cyclic-voltammetry, CV, chrono-amperometry, CA, and chrono-coulometry, CC). The amount of absorbed H will be related to the size and shape of Pd-NPs to identify parameters that define their absorbing capacity. Absorption isotherms will be prepared to examine thermodynamics of the process and materials science techniques to analyze the structure of Pd-NPs upon H ingress. We will investigate composition-size-structure-reactivity phenomena in electrocatalysis by studying mechanisms and kinetics of the oxygen reduction and evolution reactions (ORR, OER). We will synthesize Pt, PtNi and PtCo nanoparticles and single crystals, and employ them as catalysts for ORR and OER. Their activity will be evaluated using electrochemical techniques (Tafel plots, polarization curves, CV, and CA). Electrochemical and analytical techniques (inductively coupled plasma mass spectrometry, ICPMS) will be used to examine degradation of these materials. Structure and composition of the electrode materials prior to and after electrochemical measurements will be analyzed using TEM, XRD, ET, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). Comparison of results will shed light on composition-size-structure-reactivity phenomena and properties. Mass changes that accompany interfacial electrochemical processes are poorly understood and require examination over a broad temperature range. We will develop and apply variable-temperature electrochemical quartz crystal nanobalance (VT-EQCN) to examine interfacial electrochemical processes, such as catalyst oxidation and degradation. The technique will reveal T-dependent structure-forming and structure-breaking processes. The research program creates an opportunity for breakthroughs and discoveries. It is ambitious and challenging but my well-trained HQP are able to successfully undertake difficult projects. Though the research is fundamental in nature, it will benefit electrochemical technologies by creating new knowledge. Finally, HQP trained as part of this project will acquire knowledge in electrochemistry and electrocatalysis, and will develop a unique set of inter-disciplinary skills, which will enhance their future careers.