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

为了满足世界的需求，我们依赖于某些商业反应系统，这些系统消耗了世界能源的很大一部分，例如用氮气生产氨肥。这是因为一个单一的催化剂材料不是最佳的，为转化所需的所有基本反应步骤。目前的催化剂系统是最好的折衷方案，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项艰巨的挑战。在美国国家科学基金会（National Science Foundation）题为“设计材料以革新和设计我们的未来”的倡议下，一个奖项将颁发给一个由教授组成的合作团队。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，以提高高能耗反应方案的效率。研究小组提出，通过纳米级合成技术制备新的级联催化剂材料，将在整体反应中具有不同功能的多个组分连接起来。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，并减少必要化学反应所需的能量输入。虽然研究团队已经展示了构建这种方法所需的单个催化剂特征所需的概念，但还需要预测模型来指导如何将这些组件连接起来，从而改进过程。该项目将开发设计复杂催化剂组件所需的多尺度模型。这些模型将通过计算设计定义的催化剂材料的实验测试进行验证和改进。将开发一种使用多组分、多活性位点材料的催化转化替代方法。活性位点之间的通信将由能量中间体的选择性运输控制。以计算为导向的设计框架将1)利用原子和电子结构方法来优化单个催化组分，2)构建耦合微动力学/输运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，利用一个位点产生活跃的质子和电子中间体，这些中间体被运送到另一个位点以减少氮。设计方法的可转移性将通过将其应用于设计级联以在碱性系统中选择性氧化生物质衍生物种来证明。无机催化级联系统的计算指导设计将展示这些多组分材料提供高效催化过程的潜力，并为其快速加速发展提供设计框架。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抽取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工作，并与合作团队接触。每个机构的研究小组将参加针对幼儿园到K-12年级的科学推广活动，如宾夕法尼亚州中部的“探索日”和密歇根州科学中心的“问专家”系列。合作小组计划在合作机构之间协调课程提供，这将为合作教学提供机会，特别是针对所有机构整合主动学习工具。

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.