Probing surface-molecule interactions of perovskite catalysts

发展可再生能源生产和储存技术是当今世界面临的主要挑战之一。合成高效、高活性和低成本的催化剂用于电化学能量转换过程，如氧还原过程，是一个国际关注的关键研究领域。为此，该项目旨在了解在功能钙钛矿颗粒和薄膜中发生的催化过程的基本原子尺度机制。这些结构在磁传感器和自旋电子学等应用中是众所周知的，但最近的研究也揭示了在碱性燃料电池（afc）中促进氧还原（或取决于氧化物材料的氧演化）的有希望的催化活性。这为AFC技术的商业化提供了巨大的机会，因为这些氧化物，如LaMnO3，比贵金属（如常用的Pt）表现出显着的经济优势。阻碍其商业化的抑制因素是高活性氧化物催化剂的发展。因此，合成具有定制性能的功能氧化物薄膜和颗粒的需求日益增长，需求集中在开发和应用表征方法来实时探测催化过程。为了解决这个问题，将采用跨学科的方法，包括化学、材料科学和显微镜。该飞行器将进行环境透射电子显微镜（ETEM）。ETEM是一种专门的仪器，能够像传统的透射电子显微镜一样提供高分辨率的成像，并具有样品室中气体压力升高的额外好处，高达大气压力的百分之几。在实践中，催化剂颗粒（和薄膜）在暴露于气体环境（如氧气或水）时可以在原子尺度上成像，以模拟真实的燃料电池条件。通过这种方式，最终决定每种催化剂活性的表面化学反应可以被实时监测，并达到原子尺度的精度。

Developing renewable energy production and storage technologies represents one of the major challenges nowadays. The synthesis of efficient, highly active, and cost-effective catalysts for use in electrochemical energy conversion processes, such as the oxygen reduction process, is a critical area of research with international interest. To this end, this project aims to the understanding of the fundamental, atomic-scale mechanisms of catalytic processes as they occur in functional perovskite particles and thin films. These structures are well known for applications such as magnetic sensors and spintronics, but recently studies have also revealed promising catalytic activity that facilitates oxygen reduction (or oxygen evolution depending on the oxide material) in alkaline fuel cells (AFCs). This presents a great opportunity for commercialisation of AFC technology, since these oxides, such as LaMnO3, exhibit a significant economic advantage over noble metals, such as the commonly used Pt. The inhibiting factor that prevents their commercialisation is the development of highly active oxide catalysts. Thus, the need for synthesis of the functional oxide thin films and particles with tailored properties is growing immensely, and the demand is focused on the development and application of characterisation methods to probe the catalytic processes in real time. To address this, an interdisciplinary approach engaging chemistry, materials science, and microscopy will be undertaken. The vehicle will be environmental transmission electron microscopy (ETEM). ETEM is a specialised instrument that is capable for delivering high-resolution imaging, as in conventional transmission electron microscopy, with the extra benefit of elevated gas pressures in the sample chamber, as high as a few per cent of atmospheric pressure. In practice, the catalyst particles (and thin films) can be imaged at atomic-scale level while exposed to gas environments, such as oxygen or water, simulating real fuel cell conditions. This way, the chemical reactions at the surfaces, which ultimately determine each catalyst's activity, can be monitored in real time and with atomic scale precision.