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

NSF-DFG Echem：阐明面、台阶和扭结在析氧和还原反应电催化中的表面结构贡献

• 批准号: 460244535
• 负责人: Dr.-Ing. Corinna Harms
• 金额: --
• 依托单位: Arbeitsgruppe Technische Chemie 1
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/460244535?language=en
• 关键词: NSF; DFG; Echem; Elucidating; Surface

Electrolysis as a key technology to generate green hydrogen uses the excess of renewable energies while fuel cells are crucial for the efficient conversion of stored chemical into electrical energy. Both technologies require oxygen electrocatalysis as counter reaction, namely the oxygen evolution reaction (OER) in electrolysis and the oxygen reduction reaction (ORR) in fuel cells. Unfortunately, their sluggish kinetics cause high overpotentials of the oxygen half-cells limiting the efficiencies and thus requiring the development of improved electrocatalysts.The overarching goal of this project is to create higher performing, more durable non-precious metal catalysts for the OER. 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 is crucial for the design of a catalyst. The proposed work program targets following goals: (i) Synthesis of electrocatalysts with defined local active sites, (ii) Synthesis of electrocatalysts with defined morphology (pores, facets, steps and kinks) and (iii) Structural characterization and determination of the activity of the developed electrocatalysts. The rock salt structure enables synthesis of shape-controlled NiO particles with (111) or (100) surfaces 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). The Richards group will develop nanoscale faceted mixed metal oxide electrocatalysts including Fe, Mn and Co by cation exchange starting from NiO. Furthermore, a series of multi-metal oxides (e.g. nickel ferrite) will be synthesized based on a modified aerogel method developed for NiO(111). The Wark group will employ electrochemical deposition as well as (microwave-assisted) hydro- and solvothermal routes to form highly porous (with ordered mesoporosity), faceted mixed metal oxides with similar stoichiometry. The electrocatalysts will be structurally characterized using e.g. advanced operando techniques like AFM or environmental X-ray photoelectron spectroscopy (E-XPS). Evaluation of the ORR and OER under operation conditions will be addressed by tests in GDE half-cells and in MEAs in test benches in the Harms group.

电解法是生产绿色氢气的关键技术，它利用了大量的可再生能源，而燃料电池是将储存的化学物质有效转化为电能的关键。这两种技术都需要氧电催化作为逆反应，即电解中的析氧反应（OER）和燃料电池中的氧还原反应（ORR）。不幸的是，它们缓慢的动力学导致氧半电池的高过电位，限制了效率，因此需要开发改进的电催化剂。我们的中心假设是，控制催化剂的表面终止和刻面暴露可以改变表面处的配位和键合环境，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、表面形态和电化学性能之间的联系对于催化剂的设计至关重要。所提出的工作方案针对以下目标：（i）合成具有确定的局部活性位点的电催化剂，（ii）合成具有确定的形态（孔、小面、台阶和扭结）的电催化剂，以及（iii）结构表征和测定所开发的电催化剂的活性。岩盐结构使得能够合成具有（111）或（100）表面的形状控制的NiO颗粒，从而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，以系统地研究用台阶和扭结定制表面的效果，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。理查兹小组将通过从NiO开始的阳离子交换开发纳米级多面混合金属氧化物电催化剂，包括Fe、Mn和Co。此外，一系列的多金属氧化物（如铁酸镍）将合成基于改进的气凝胶方法开发的NiO（111）。Wark小组将采用电化学沉积以及（微波辅助）水热和溶剂热路线，以形成具有相似化学计量的高度多孔（具有有序的介孔性），多面混合金属氧化物。电催化剂将使用例如先进的操作技术如AFM或环境X射线光电子能谱（E-XPS）进行结构表征。将通过在GDE半电池中进行的测试和在伤害组测试台架中进行的MEA中进行的测试来解决操作条件下ORR和OER的评价。