Understanding CO2 Reduction Catalysts

如果我们要找出提高催化效率的障碍在哪里，了解和开发绕过这些障碍的方法，监测材料的原位和原位催化性能的必要性是至关重要的。光电子能谱(PES)是一种广泛使用的多学科技术，广泛用于研究材料表面的成分和化学。这是一种超高压技术，这意味着不可能研究固-气界面和相应的反应性。高压光电子能谱(HIPPS)是先进的表面表征技术的前沿，因为它现在可以在与技术应用高度相关的近环境压力下测量表面化学和物理。标准光电子能谱是在超高压(10-9mbar)压力范围内进行的，而HIPPE测量是在压力大于10mbar时进行的。这意味着可以在高度相关的条件下(例如，压力、温度、湿度、酸度的函数)监测表面反应；这与传统光谱仪的强烈还原条件形成鲜明对比，传统光谱仪不仅不提供动态信息，而且可能实际上改变所研究体系的表面化学。我们的目标是使用HIPPES技术来研究纳米铜颗粒和二氧化碳之间的表面化学。通过监测气固界面的相互作用，我们的目标是确定催化活性中心的性质，并提出基于证据的机制，在铜上还原二氧化碳。我们将研究表面化学作为温度、共吸附物质(如水和O2)和pH的函数。我们希望更详细地了解这些纳米催化剂，以提高催化效率，或发现新的催化剂，从而使碳捕获和利用技术的经济可行性成为可能。

The need to monitor the synthesis and catalytic performance of materials in-situ and in-operando is of critical importance if we are to find where the barriers to increased catalytic efficiency are, and understand and develop methodologies to circumvent them. Photoelectron spectroscopy (PES) is a widely used multidisciplinary technique widely used to study the composition and chemistry of material surfaces. It is an UHV technique, meaning that it is not possible to investigate the solid-gas interface and consequential reactivity. High-pressure photoelectron spectroscopy (HiPPES) is at the forefront of advanced surface characterization techniques as it now allows the measurement of surface chemistry and physics at near-environmental pressures that are highly relevant for technological applications. Whereas standard photoelectron spectroscopy is performed in the UHV (10-9 mbar) pressure range, HiPPES measurements are performed at pressures greater than 10 mbar. This means that surface reactions can be monitored under highly relevant conditions (e.g. as a function of pressure, temperature, humidity, acidity); in stark contrast to the strongly reducing conditions of a conventional spectrometer which not only provide no dynamic information, but may also actually alter the surface chemistry of the system under study. We aim to use the HiPPES technique to the surface chemistry taking place between copper nanoparticles and CO2. By monitoring the interactions of the gas-solid interface we aim to determine the nature of catalytic active sites, and propose evidence-based mechanisms for the reduction of CO2 on copper. We will study the surface chemistry as a function of temperature, co-adsorbates (such as water and O2) and pH. We hope to understand these nanocatalysts in greater detail, to raise the catalytic efficiency, or to discover new catalysts, thereby enabling the economic viability of carbon capture and utilisation technologies.