Structural Evolution of a High-Temperature Oxygen Evolution Catalyst under Transient Working Conditions

瞬态工况下高温析氧催化剂的结构演化

• 批准号: 493709258
• 负责人: Professor Dr. Rüdiger-A. Eichel
• 金额: --
• 依托单位: IEK-9: Grundlagen der Elektrochemie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2022
• 资助国家: 德国
• 起止时间: 2021-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/493709258?language=en
• 关键词: Structural; Evolution; Temperature; Oxygen; Catalyst

Solid oxide electrolysis cells (SOECs) as an efficient power-to-X (P2X) conversion technology for chemical storage of intermittent renewable energy suffer from poorly understood degradation processes under steady and dynamic operating conditions. In the first project phase a qualitatively new description of the anode/electrolyte interface was gained which was identified as a nano-scale complexion. This finding forms the basis of the following funding period in which we propose to investigate, the air electrode/electrolyte interface of the SOEC under dynamic operating conditions. We will build upon our tightly interwoven multi-modal microscopic, spectroscopic, and first-principle theoretical approach developed during the first project phase and extend it to near-ambient operando and quasi in situ conditions. The outcome of this multi-modal study will rationalize structural factors that influence the catalytic activity and related degradation processes. We will focus on LSM based electrolysis cells, which will be characterized electrochemically under constant and dynamic reaction conditions. The aim of this project is the evaluation of the complexion under reaction conditions in order to deliver evidence for its role in the electrochemical process. Ex situ analysis of the surface and the air electrode/electrolyte interface will be performed by electron microscopy and photoelectron spectroscopy. For the study of the structure and the oxidation states of the cations with correlative environmental scanning electron microscopy (ESEM) and operando X-ray photoelectron spectroscopy special cells will be prepared. The cells will be produced by the deposition of LSM (< 10 nm) on an YSZ substrate. This very thin electrode layer will allow the photoelectrons emanating from the complexion to leave the electrochemically active domain. The formation and stability of the complexion in the thin cells will be studied under constant and dynamic loads. Identical location TEM imaging (ILI) will complement the ex situ analysis and act as a structural basis to subsequent operando experiments. The experimental investigations will be complemented by DFT calculations. Starting from large complexion models of the YSZ/LSM interface, produced by force-field based sampling techniques, we will generate ensembles of DFT tractable model cells where each ensemble is representative of a thin section within the complexion that is parallel to the YSZ/LSM interface. To establish the properties of the complexion as a mixed conductivity (MIEC) of catalytically active interface structure, activation barriers for the hopping processes along the oxide ion conduction pathways will be computed using NEB DFT simulations within the small DFT cell ensembles generated. The optimal MIEC slice will be used to construct slab models representing possible surface configurations at the catalytically active site.

固体氧化物电解电池（SOECs）作为一种用于间歇性可再生能源的化学储存的有效的功率到X（P2 X）转换技术，在稳定和动态操作条件下遭受知之甚少的降解过程。在第一个项目阶段，获得了阳极/电解质界面的定性新描述，其被确定为纳米级复合物。这一发现形成了以下资金周期的基础上，我们建议调查，在动态操作条件下的SOEC的空气电极/电解质界面。我们将建立在我们紧密交织的多模态微观，光谱和第一原理理论方法在第一个项目阶段开发，并将其扩展到近环境操作和准原位条件。这一多模式研究的结果将使影响催化活性和相关降解过程的结构因素合理化。我们将专注于基于LSM的电解电池，其特征在于在恒定和动态反应条件下的电化学。该项目的目的是评估反应条件下的络合物，以提供其在电化学过程中的作用的证据。将通过电子显微镜和光电子能谱法对表面和空气电极/电解质界面进行非原位分析。为了用相关的环境扫描电子显微镜（ESEM）和操作X射线光电子能谱研究阳离子的结构和氧化态，将制备特殊的电池。将通过在YSZ衬底上沉积LSM（< 10 nm）来生产电池。该非常薄的电极层将允许从络合物发出的光电子离开电化学活性域。将在恒定和动态载荷下研究薄电池中络合物的形成和稳定性。相同位置的TEM成像（ILI）将补充非原位分析，并作为结构基础，以随后的operando实验。DFT计算将补充实验研究。从大肤色模型的YSZ/LSM接口，力场为基础的采样技术，我们将产生合奏DFT易处理的模型细胞，每个合奏是代表一个薄的部分内的肤色是平行的YSZ/LSM接口。为了建立作为催化活性界面结构的混合导电性（MIEC）的络合物的性质，将使用在所生成的小DFT单元系综内的NEB DFT模拟来计算用于跳跃过程沿着氧化物离子导电路径的活化势垒。最佳MIEC切片将用于构建板模型，代表催化活性部位可能的表面构型。