DMREF/Collaborative Research: Computationally Guided Design of Multicomponent Materials for Electrocatalytic Cascade Reactions

为了满足世界需求，我们依赖于某些商业反应系统，这些系统消耗了世界上很大一部分能源，例如从氮气中生产氨肥。这是因为一种单一的催化剂材料并不是转化所需的所有基本反应步骤的最佳选择。目前的催化剂体系是最好的折衷方案，但效率低下。然而，通过应用新的催化剂材料来改善这种能源昂贵的状况是一个令人生畏的挑战。在国家科学基金会名为设计材料以革新和设计我们的未来的倡议下，一个由教授组成的合作团队正在获奖。Michael Janik(宾夕法尼亚州立大学)、Suljo Linic(密歇根大学)、Will Medlin(科罗拉多大学)和Eranda Nikolla(韦恩州立大学)共同开发新的多组分催化剂材料，使高耗能反应方案具有更高的效率。该研究小组提出，通过纳米级合成技术来制备新的级联催化剂材料，以连接在整个反应中具有不同功能的多个组分。原则上，这些催化材料组分的紧密连接可以减少不需要的和对环境有害的副产品的形成，并减少必要的化学反应所需的能量投入。虽然研究小组已经展示了构建这种方法所需的单个催化剂功能所需的概念，但需要预测模型来指导如何将这些组件联系起来以改进工艺的设计。该项目将开发设计复杂催化剂组件所需的多比例模型。这些模型将通过由计算设计定义的催化剂材料的实验测试来验证和改进。将开发一种使用多组分、多活性中心材料的催化转化的替代方法。活性中心之间的通信将由含能中间体的选择性运输控制。计算指导的设计框架将1)利用原子学和电子结构方法来优化单个催化组分，以及2)构建一个耦合的微观动力学/传输模型来指导多组分材料的构建。合成、制造、表征和反应性研究将验证计算模型并实现催化剂提供的增强功能。最初的催化剂开发工作将集中在氨合成上，使用一个地点来产生活性质子和电子中间体，并将其输送到第二个地点来还原氮。设计方法的可转移性将通过将其应用于设计用于碱性系统中生物质衍生物种的选择性氧化的级联来证明。计算指导的无机催化级联体系的设计将展示这些多组分材料提供高效催化过程的潜力，并为快速加速其发展提供设计框架。这项研究将与教育和外联活动结合起来，以扩大拟议工作的影响。从针对代表性不足群体的项目中挑选出来的本科生研究人员将被整合到四个合作机构的研究工作中，让这些学生参与多学科的工作，并接触到合作团队。每个机构的研究小组将通过K-12小组参加针对学龄前儿童的科学推广活动，例如宾夕法尼亚州中部的“探索日”和密歇根科学中心的“询问专家”系列活动。合作小组计划协调伙伴机构之间的课程设置，这将为合作教学提供机会，具体目的是整合所有机构的积极学习工具。

In order to support world needs, we depend on certain commercial reaction systems that consume a significant fraction of the world's energy resources, such as for the production of ammonia fertilizers from nitrogen gas. This is because one single catalyst material is not optimal for all the elementary reaction steps that are required for a conversion. The current catalyst system is the best compromise, but is inefficient. Improving upon this energy-costly situation through application of new catalyst materials is a daunting challenge, however. Under the National Science Foundation initiative titled Designing Materials to Revolutionize and Engineer our Future, an award is being made to a collaborative team of Profs. Michael Janik (Pennsylvania State University), Suljo Linic (University of Michigan), Will Medlin (University of Colorado) and Eranda Nikolla (Wayne State University) to develop new multicomponent catalyst materials that will allow greater efficiency in energy-demanding reaction schemes. The research team proposes that new cascade catalyst materials be prepared by nanoscale synthesis techniques to link the multiple components that have different functions in an overall reaction. Close linking of these catalytic material components, in principle, can reduce the formation of unwanted and environmentally hazardous byproducts and decrease the required energy input for necessary chemical reactions. While the research team has demonstrated the concepts required to construct the individual catalyst features required for this approach, predictive models are needed to guide the design of how to link these components to result in an improved process. This project will develop the multi-scale models necessary to design complex catalyst assemblies. These models will be validated and refined through experimental testing of catalyst materials defined by computational designs. An alternative approach to catalytic conversion will be developed using multi-component, multi-active site materials. Communication between active sites will be controlled by the selective transport of energetic intermediates. A computationally-guided design framework will 1) utilize atomistic and electronic structure methods to optimize individual catalytic components, and 2) construct a coupled microkinetic/transport model to guide construction of the multi-component material. Synthesis, fabrication, characterization, and reactivity studies will validate computational models and realize the enhancements offered by the catalysts. Initial catalyst development efforts will concentrate on ammonia synthesis, using one site to generate active proton and electron intermediates that transport to a second site to reduce nitrogen. Transferability of the design approach will be demonstrated by applying it to design cascades for selective oxidation of biomass-derived species in alkaline systems. The computationally guided design of inorganic catalytic cascade systems will both demonstrate the potential of these multi-component materials to provide efficient catalytic processes and provide a design framework for rapid acceleration of their development. The research will be integrated with educational and outreach activities to broaden the impact of the proposed work. Undergraduate researchers drawn from programs that target underrepresented groups will be integrated into research efforts at the four partner institutions, involving these students in multi-disciplinary work with exposure to the collaborative team. Research groups at each institution will participate in science outreach activities targeted at preschool through K-12 groups, such as Central Pennsylvania's "Exploration Days" and the Michigan Science Center's "Ask the Expert" series. The collaborative group plan coordinated course offerings among the partner institutions, which will provide opportunities for collaborative teaching, specifically aimed at integrating active learning tools at all the institutions.