Probing surface-molecule interactions of perovskite catalysts

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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.