DMREF: Collaborative Research: Transforming Electrocatalysis using Rational Design of Two Dimensional Materials

该项目将采用综合理论和实验方法，快速发现基于二维（2D）材料与离子液体接触的高效催化剂，用于各种对可持续能源生产、化学品制造、环境修复和能源储存具有重要意义的电化学反应。电催化-用于能量存储和转换设备，如先进的电池，燃料电池，光伏和化学电解槽-正在成为传统热催化的越来越重要的替代方案，但需要进一步提高效率，降低成本，以及大规模商业实施的化学选择性。该项目将通过结合第一性原理密度泛函数理论计算（包括溶剂相互作用效应和理论指导的机器学习）来解决这些需求，以确定新的离子液体电解质和低成本2D材料，这些材料能够利用可再生和/或可持续资源的电催化过程取代现有的热过程。该项目的教育和推广部分将侧重于为研究生和本科生准备实现先进能源技术所需的劳动力。两所大学的重点将放在通过现有项目招募少数族裔和代表性不足的学生群体上，包括伊利诺伊大学芝加哥分校的少数族裔工程招聘和保留项目（MERRP）和华盛顿大学本科研究办公室。研究中生成的二维材料的理论和实验数据集，以及相关的计算代码，将通过在线存储库传播给更广泛的研究社区。与离子液体（IL）电解质接触的二维过渡金属二硫族化合物（TMDCs）将被用作起始材料，为基于低功函数、d带部分态密度与费米能量显著重叠的材料以及保护而不是污染催化位点的电解质“溶剂”的电催化提供新的范例。新的材料组合和结构将使用计算工具进行预测，然后使用化学气相沉积、化学气相输运和胶体化学进行合成。原子和电子结构将使用原位像差校正扫描透射电子显微镜（STEM）进行表征。从高分辨率STEM中获得的信息，包括高角度环形暗场（HAADF）和环形明场（ABF）成像，以及电子能量损失光谱（EELS）和能量色散x射线光谱（XEDS），将用于确认所需结构的成功合成，并为第一原理建模工作创建起始配置。将进行非原位和原位电化学实验来测量合成材料的活性和选择性。特别是，该研究将利用一种新型石墨烯液体电池，该电池由一名研究人员开发，可以在液体环境中实现原子分辨率成像和光谱。电催化反应的机理研究和传输测量将利用原位差分电化学质谱（dem）和传统的氮化硅电化学阶段在操作条件下进行STEM表征。总之，先进的合成、表征和评估技术，加上高效的计算搜索方法，将加速发现具有优越活性和选择性的二维材料基催化剂，用于各种电化学反应，包括氧还原反应（在燃料电池技术中很重要）和析氢反应（在水电解中很重要）。

The project will employ an integrated theoretical and experimental approach to rapidly discover highly efficient catalysts, based on two-dimensional (2D) materials in contact with an ionic liquid, for a variety of electrochemical reactions of importance for sustainable energy generation, chemicals manufacturing, environmental remediation, and energy storage. Electrocatalysis - as employed in energy storage and conversion devices such as advanced batteries, fuel cells, photovoltaics, and chemical electrolyzers - is becoming an increasingly important alternative to conventional thermal catalysis, but needs further improvements in efficiency, cost reduction, and chemical selectivity for wide-scale commercial implementation. The project will address those needs by combining first-principles density functional theory calculations, including solvent interaction effects and theory-guided machine learning, to identify new ionic-liquid electrolytes and low-cost 2D materials capable of displacing existing thermal processes with electrocatalytic processes utilizing renewable and/or sustainable resources. Educational and outreach components of the project will focus on preparing both graduate and undergraduate students for the workforce needed to realize advanced energy technologies. Emphasis at both universities will be placed on the recruitment of minority and underrepresented student populations through existing programs including the Minority Engineering Recruitment and Retention Program (MERRP) at the University of Illinois-Chicago, and the Office of Undergraduate Research at Washington University. The theoretical and experimental dataset on 2D materials generated in the study, along with relevant computational codes, will be disseminated to the broader research community through on-line repositories.Two-dimensional transition metal dichalcogenides (TMDCs) in contact with ionic liquid (IL) electrolytes will be used as the starting materials offering a new paradigm for electrocatalysis based on materials with low work function, significant overlap of the d-band partial density of states with the Fermi energy, and an electrolyte 'solvent' that protects rather than poisons the catalytic sites. Novel material combinations and structures will be predicted using computational tools and then synthesized using chemical vapor deposition, chemical vapor transport and colloidal chemistry. Atomic and electronic structure will be characterized using in-situ aberration-corrected scanning transmission electron microscopy (STEM). The information obtained from high-resolution STEM, including high-angle annular dark-field (HAADF) and annular bright-field (ABF) imaging, as well as electron energy loss spectroscopy (EELS) and energy dispersive X-ray spectroscopy (XEDS), will be used to confirm successful synthesis of the desired structures and to create starting configurations for the first-principles modeling efforts. Both ex-situ and in-situ electrochemical experiments will be conducted to measure the activity and selectivity of the synthesized materials. In particular, the study will utilize a novel graphene liquid cell, developed by one of the investigators, that enables atomic-resolution imaging and spectroscopy in a liquid environment. Mechanistic studies of the electrocatalytic reactions and transport measurements will be made utilizing in-situ differential electrochemical mass spectrometry (DEMS) together with a traditional silicon nitride based electrochemical stage for STEM characterization under operando conditions. Taken together, the advanced synthesis, characterization, and evaluation techniques, coupled with efficient computational search methods, will accelerate the discovery of 2D material-based-catalysts with superior activity and selectivity for various electrochemical reactions including the oxygen reduction reaction (important in fuel cell technology), and the hydrogen evolution reaction (important in water electrolysis).