SusChEM: Anchoring Single Noble Metal Atoms for Better Catalysis

SusChEM：该项目由亚利桑那州立大学的Jingyue（Jimmy）Liu开展，解决了合成单原子催化剂时遇到的基本科学概念，测试其功效，建立其结构-功能关系，并开发新的策略来稳定活性贵金属的孤立单原子。负载型贵金属催化剂在能源转换、化学转化和改善环境质量方面发挥着核心作用。然而，贵金属通常非常昂贵。贵金属的有效利用是开发和应用贵金属催化剂的关键因素。原子效率和比活性（即，每原子的活性）通常随着颗粒尺寸的减小而增加，尺寸减小的极限是单个原子的尺寸减小。刘博士的方法是将单个原子锚在纳米结构的支持物上，以使它们稳定并防止它们聚集在一起。 在这项研究中获得的见解正在用于指导下一代能源和环境应用催化剂的分子设计。本研究中学到的知识通过减少有限和昂贵的原材料的使用并降低商品成本，促进了对促进化学品可持续性的更广泛社会影响。 更广泛的影响，通过教育提供了一个年度冬季讲习班的高分辨率电子显微镜，主要由研究生参加，并通过约翰C。惠特利教育和推广设施致力于促进K-12年级学生的科学素养。有了这个奖项，美国亚利桑那州州立大学的刘景岳博士，正由化学系的化学催化项目和材料科学系的固态与材料项目共同资助，对负载型贵金属单原子催化剂（SAC）的结构和反应性进行基础研究和外延锚定的簇。Liu博士的团队专注于开发具有高水平金属负载的SAC并了解原子-载体相互作用，目标是稳定单个贵金属原子（Pt 1，Au 1，Pd 1，Ir 1和Rh 1）和Fe 3 O 4/Fe 2 O3（可还原），Al 2 O3（不可还原）和ZnO（难以还原）载体纳米结构上的纳米团簇。这些催化反应包括Pd/ZnO催化甲醇水蒸气重整制氢反应，Ir/Fe_3 O_4（Fe_2 O_3）和Au/Fe_3 O_4催化水煤气变换反应，Pd/Al_2 O_3、Pt/Al_2 O_3和Rh/Al_2 O_3催化CO氧化反应。 Liu博士的团队依靠像差校正电子显微镜（ACEM）技术，特别是环境ACEM，来明确识别高表面积支撑物上孤立的单个贵金属原子和外延纳米团簇的分布，并在高温下的环境气压环境下跟踪纳米团簇运动。原位和非原位催化反应数据进行了详细分析，以了解负载的单原子和簇催化剂的合成-结构-性能关系，特别强调与能量转换，化学转化和环境应用有关的催化反应。 更广泛的影响，通过教育提供了一个年度冬季讲习班的高分辨率电子显微镜，主要由研究生参加，并通过约翰C。惠特利教育和推广设施致力于促进K-12年级学生的科学素养。

SusChEM: Anchoring Single Noble Metal Atoms/Clusters for Better CatalysisThis project, carried out by Jingyue (Jimmy) Liu at Arizona State University, addresses fundamental scientific concepts encountered in synthesizing single-atom catalysts, testing their efficacy, establishing their structure-function relationships, and developing new strategies to stabilize isolated, single atoms of active noble metals. Supported noble metal catalysts play a central role in energy conversion, chemical transformations, and the improved quality of our environment. Noble metals are, however, usually very expensive. The efficient use of noble metals is a critical factor in developing and applying noble metal catalysts. The atom efficiency and specific activity (i.e., activity per atom) generally increases with decreasing particle size, with the ultimate limit of size reduction that of a single atom. Dr. Liu's approach is to anchor the single atom onto nanostructured supports to immobilize them and prevent them from clustering together. The insights gained in this investigation are being used to guide the molecular design of next-generation catalysts for energy and environmental applications. The knowledge learned in this study promotes societal broader impact in fostering chemical sustainability by reducing the usage of limited and expensive raw materials and lowering the costs of goods. Broader impacts through education are offered in an annual Winter Workshop of High Resolution Electron Microscopy, attended primarily by graduate students, and through the John C. Wheatley Education and Outreach Facility dedicated to the promotion of scientific literacy in K-12 grade students.With this award, the Chemical Catalysis Program in the Chemistry Division and the Solid State and Materials Program in the Division of Materials Science are jointly funding Dr. Jingyue (Jimmy) Liu from Arizona State University to conduct fundamental studies of structure and reactivity of supported noble metal single-atom catalysts (SACs) and epitaxially-anchored clusters. Dr. Liu's group focuses on developing SACs with high levels of metal loading and understanding the atom-support interactions, with a goal of stabilizing single noble metal atoms (Pt1, Au1, Pd1, Ir1 and Rh1) and nanoclusters on nanostructures of Fe3O4/Fe2O3 (reducible), Al2O3 (non-reducible), and ZnO (difficult to reduce) supports. The proposed catalytic reactions include Pd/ZnO for steam reforming of methanol to produce hydrogen, Ir/Fe3O4 (Fe2O3) and Au/Fe3O4 for the water-gas-shift reaction, and Pd/Al2O3, Pt/Al2O3 and Rh/Al2O3 for CO oxidation. Dr. Liu's group relies on aberration-corrected electron microscopic (ACEM) techniques, especially environmental ACEM, to identify unambiguously the distribution of isolated single noble metal atoms and epitaxial nanoclusters supported on high-surface-area supports and to follow the nanocluster movement under ambient gas pressure environments at elevated temperatures. Both in situ and ex situ catalytic reaction data are analyzed in detail to understand the synthesis-structure-property relationships of supported single atom and cluster catalysts with a particular emphasis on catalytic reactions relevant to energy conversion, chemical transformations, and environmental applications. Broader impacts through education are offered in an annual Winter Workshop of High Resolution Electron Microscopy, attended primarily by graduate students, and through the John C. Wheatley Education and Outreach Facility dedication to the promotion of scientific literacy in K-12 grade students.