Operando high-pressure combined sXAS/XPS investigation into the state of active Zn for CO2 activation with atomically engineered ZnO on Cu inverse nanoparticle catalysts

This experiment aims to investigate the nature of the active Zn species using ZnO on Cu inverse nanoparticle catalysts for methanol production from CO2 hydrogenation under a realistic gas environment and pressure (up to 4 bar). Currently, there is a growing interest in producing methanol from recycled CO2 via direct CO2 hydrogenation. Cu ZnO Al2O3-based catalysts have been the benchmark catalyst industrial application in methanol synthesis from syngas for the past 50 years. However, they show poor activity inCO2-rich feeds and a deeper understanding of the active sites is critical to achieve high methanol yield. With the aid of operando sXAS and XPS measurement and using atomically engineered ZnO on Cu inverse nanoparticle catalysts, we hope to elucidate the true nature of the Zn active species under industrially relevant conditions. We have recently developed and performed in situ/operando atmospheric pressure (up to 4 bar) combined XPS and XAS measurement at BL24 - CIRCE, ALBA, and B07- C, Diamond Light Source, at temperatures up to 400 °C and with realistic gas composition. This setup uses continuous graphene supported on perforated SiNx membranes, an X-ray/photoelectron transparent window, onto which catalyst nanoparticles (e.g. Cu and Zn) can be deposited. By probing the catalyst surface as a function of ZnO layer thickness under a realistic gas environment, we will reveal the chemical state Zn on the Cu nanoparticle catalysts and provide a new understanding of the interaction between surface Cu and Zn. This, when correlated with catalytic activity and selectivity information, will shed new light on the true nature of active Zn species, its influence on Cu/Zn synergistic effects and their relationship to catalytic activity.