Capturing Surface Dynamics in CO₂/Cu(111), CO/Ni(111), and FeOₓ/CeO₂ Model Systems by Integrated Near-Ambient-Pressure Spectroscopy and Microscopy”

We present an integrated experimental platform at the Department of Surface and Plasma Physics, Charles University, Prague, operated within the Nanomaterials Group and available to the scientific community through the open-access CERIC-ERIC framework. The system combines near-ambient-pressure X-ray photoelectron spectroscopy (NAP-XPS), near-ambient-pressure scanning tunnelling microscopy (NAP-STM), and polarization-modulation infrared reflection absorption spectroscopy (PM-IRRAS) within a single ultrahigh-vacuum system. This configuration enables quasi-in situ characterization of the same samples using complementary structural, chemical, and vibrational techniques.

The capabilities of the system are demonstrated on several model catalytic systems. NAP-STM measurements of CO adsorption on Ni(111) provide atomically resolved images from UHV conditions to approximately 50 mbar, revealing dense CO layers and tip-induced surface changes at elevated pressures. Complementary NAP-STM and NAP-XPS measurements of CO₂ on Cu(111) demonstrate pronounced differences between static and flowing exposures, highlighting the role of CO accumulation and gas-phase back-reaction. Finally, studies of FeOₓ/CeO₂(111) reveal redox-driven restructuring, including Fe diffusion into the ceria bulk under reducing conditions and surface segregation and agglomeration under oxidizing conditions. Initial PM-IRRAS measurements further demonstrate the potential of the recently completed vibrational spectroscopy capability.

These examples illustrate how integrating complementary techniques within a single UHV platform enables a more comprehensive view of dynamic surface processes under reaction-relevant conditions.