NSF-DFG Echem: Elucidating Surface Structure Contribution of Facets, Steps and Kinks in Electrocatalysis of the Oxygen Evolution and Reduction Reactions

该项目是科罗拉多矿业学院（美国）、国家可再生能源实验室（美国）、奥尔登堡卡尔·冯·奥西茨基大学（德国）和德国航空航天中心-德国<s:1> Luft- und Raumfahrt中心（DLR）之间的国际合作。电解是利用可再生能源生产绿色氢的关键技术，而燃料电池是将储存的能量转化为电能的关键技术。这两种技术都需要催化剂，但目前催化剂的动力学缓慢限制了它们的效率，因此需要改进电催化剂的发展。目前，水电解槽和燃料电池使用的金属既稀缺又昂贵，因此限制了大规模的商业化。在这个研究项目中，我们的目标是通过对表面的基础研究和操作，以金属氧化物的形式使用地球丰富的材料，如第一排过渡金属（Ni, Fe, Co， Mn或Cu）作为电催化剂。这个项目汇集了美国和德国的科学家和工程师，共同致力于这个具有挑战性的项目，从而为参与其中的学生提供了独特的教育体验。该项目的总体目标是为析氧反应（OER）和氧还原反应（ORR）创造性能更高、更耐用的非贵金属催化剂。阴离子交换膜（AEM）的化学性质决定了碱性条件，使得AEM水电解（AEMWE）中的OER和AEM燃料电池（AEMFC）中的ORR的替代催化材料得以使用。岩盐结构可以合成具有（111）或（100）表面的形状控制的金属氧化物颗粒，这对于尖晶石或钙钛矿等其他晶体结构来说是不容易实现的，允许阐明它们在氧电催化中的作用。此外，这些材料提供了理想的平台，可以系统地研究用台阶和扭结剪裁表面的效果，以及用类似离子半径的元素（例如Co， Mn, Fe）制造多金属氧化物。我们的中心假设是，控制催化剂的表面终止和表面暴露可以改变表面的配位和键合环境，从而改变反应物-催化剂相互作用和电催化OER/ORR活性。因此，合成、表面形貌和电化学性能之间的联系将为催化剂的设计提供至关重要的基础知识。这项研究是由NSF- dfg牵头机构在电合成和电催化活动（NSF- dfg化学）机会NSF 20-578资助的。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This project is an international collaboration between the Colorado School of Mines (USA), the National Renewable Energy Laboratory (USA), Carl von Ossietzky University Oldenburg (Germany) and the German Aerospace Center-Deutsches Zentrum für Luft- und Raumfahrt (DLR) in Germany. Electrolysis is a key technology to generate green hydrogen using renewable energies while fuel cells are crucial for converting stored energy into electrical energy. Both technologies require catalysts which currently struggle with sluggish kinetics limiting their efficiencies and thus requiring the development of improved electrocatalysts. Currently, water electrolyzers and fuel cells use metals that are scarce and expensive thereby limiting large-scale commercialization. In this research program we target the use of earth abundant materials such as first row transition metals (Ni, Fe, Co, Mn or Cu) in the form of metal oxides as electrocatalysts through fundamental study and manipulation of the surfaces. This project brings together American and German scientists and engineers to work on this challenging project thus providing a unique educational experience for the students involved.The overarching goal of this project is to create higher performing, more durable non-precious metal catalysts for the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). Alkaline conditions established by the chemical nature of an anion exchange membrane (AEM) enable the usage of alternative catalytic materials for the OER in AEM water electrolysis (AEMWE) and ORR in AEM fuel cells (AEMFC). The rock salt structure enables synthesis of shape-controlled metal oxide particles with (111) or (100) surfaces, which are not (easily) achievable for other crystal structures like spinels or pervoskites, allowing elucidation of their role in oxygen electrocatalysis. Further, these materials offer ideal platforms to systematically study the effects of tailoring the surfaces with steps and kinks and making multi-metal oxides with elements of similar ionic radii (e.g. Co, Mn, Fe). Our central hypothesis is that controlling the surface termination and facet exposure of a catalyst can alter the coordination and bonding environments at the surface thus changing the reactant-catalyst interaction and the electrocatalytic OER/ORR activity. Therefore, the connection between synthesis, surface morphology and electrochemical performance will provide the underlying fundamental knowledge crucial for the design of catalysts.This research was funded under the NSF-DFG Lead Agency Activity in Electrosynthesis and Electrocatalysis (NSF-DFG EChem) opportunity NSF 20-578.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.