In Situ Nanoscale Study of Electrocatalysts for Renewable Fuels

可再生能源在当今电力系统中发挥着越来越重要的作用。可再生化学燃料(水分解产生的氢气或二氧化碳减少产生的燃料)可用于储存太阳能或风能等间歇性能源的过剩产量，以供未来在电网上使用。储能解决方案的成功取决于找到新材料并优化其性能和在其表面发生的反应。电极/电解液界面的结构和性质随环境和外加电位的不同而变化。我的研究计划的总体目标是在现实条件下，使用原位方法研究这些界面，以获得界面上实际活性结构的信息，并创造出性能更好的新催化剂。扫描探针显微镜(SPM)和等离子体增强拉曼光谱等方法可以获得高灵敏度、表面特异性和纳米级分辨率。在高分辨率实验中，SPM针尖将被用作增强的拉曼热点，以10 nm或更高的分辨率原位绘制界面纳米尺度的化学结构图，这一技术被称为针尖增强拉曼光谱(TERS)。拟议的研究计划结合了几个策略来实现我的目标：1.由层状双氢氧化物(LDH)和2D过渡金属氮化物/碳化物材料(MXenes)制成的用于可再生燃料的纳米片电催化剂是生产氢气的廉价电催化剂的突出候选者。众所周知，这些材料的结构在催化条件下会发生变化，而活性对掺杂剂的存在和局部结构(基面、台阶、表面功能化)很敏感。我和我的学生将进行纳米级的原位测量，以揭示局部结构与活性的关系，从而指导催化剂结构的优化。2.我的团队将研究混合等离子体电催化剂，这种催化剂在可见光下具有等离子体共振，并可以在表面注入高能电荷载流子。这种组合将提高催化剂的整体性能，并使我们能够更好地控制选择性。学生将首先学习双金属等离子体催化剂，然后将光学活性等离子体结构与催化活性部分相结合：(A)附着在金属表面的分子催化剂，(B)在我的发现计划背景下创建的LDH和MXenes纳米片材。在新创建的等离子体/催化界面上，将存在新的催化位置，它们将呈现不同的活性和选择性。由此产生的专业知识和仪器将在加拿大独一无二。我的发现号研究计划将为未来先进材料的工作奠定基础，如金属有机骨架(MOF)、过渡金属二卤化物和2D碳材料，以解决可再生能源和可持续发展问题。

The energy produced from renewable resources is playing an increasingly important role in today's power systems. Renewable chemical fuels (H2 from water splitting or fuels produced from CO2 reduction) can be used to store excess production of intermittent sources such as solar or wind for future use on the grid. The success of energy storage solutions depends on finding new materials and optimizing their properties and the reactions that occur at their surface. The structure and properties of electrode/electrolyte interfaces change depending on the environment and the applied potential. The overarching goal of my research program is to study these interfaces under realistic conditions, using in situ methods so as to gain information on the actual active structures at the interface and create new catalysts with improved performance. Methods such as scanning probe microscopy (SPM) and plasmonically enhanced Raman spectroscopy can achieve high sensitivity, surface specificity and nanoscale resolution. In high resolution experiments, an SPM tip will be used as an enhanced Raman hotspot to map the chemical structure at the nanoscale of the interface in situ with a resolution at 10nm or better, a technique known as tip enhanced Raman spectroscopy (TERS). The proposed research program combines several strategies to achieve my goal: 1. Nanosheet electrocatalysts for renewable fuels made of layered double hydroxides (LDH) and 2D transition metal nitrides/carbides materials ("MXenes") are prominent candidates for affordable electrocatalysts for the production of H2. The structure of these materials is known to change under catalytic conditions, while the activity is sensitive to the presence of dopants and the local structure (basal plane, steps, surface functionalization). My students and I will perform nanoscale in situ measurements to unravel local structure-activity relationships so as to guide the optimization of catalyst structure. 2. My team will investigate hybrid plasmonic electrocatalysts that possess a plasmonic resonance in the visible and can inject energetic charge carriers at the surface. This combination will increase the overall performance of the catalyst and give us a better control over the selectivity. Students will first study bimetallic plasmonic catalysts and will then combine optically active plasmonic structures with a catalytically active part: (a) molecular catalysts attached on the metal surface and (b) nanosheets of LDH and MXenes created in the context of my Discovery program. At the newly created plasmonic/catalytic interface, new catalytic sites will exist that will present a different activity and selectivity. The resulting expertise and instrumentation will be unique in Canada. My Discovery research program will be the foundation for future work on advanced materials such as metal organic frameworks (MOF), transition metal dichalcogenides and 2D carbon materials to solve renewable energy and sustainability problems.