A UHV-compatible flow reactor for model catalytic reactions under realistic conditions combined with catalyst cluster...

The study of model catalysts under complex reaction conditions needs to address several challenges, including high-sensitivity detection and accurate control of reaction pressure and temperature, while ensuring a contamination-free environment. Here, we developed an ultra-high vacuum (UHV)-compatible flow reactor designed to investigate model catalytic reactions. The reactor is integrated into an existing UHV system, which facilitates the synthesis of mass-selected clusters and their controlled deposition on model substrates. The combination of the flow reactor with the preparation system enables catalyst preparation, characterization, and testing without exposure to ambient conditions. The reaction cell features a dual-cup design with a reaction volume of less than 3 ml and is equipped with a near-infrared laser heater and a quadrupole mass spectrometer for continuous product analysis. The gas handling unit allows for the use of different gas mixtures flowing at various pressures through the reaction cell. The laser heating unit provides precise temperature regulation through programmable heating and cooling profiles. As a proof of concept, catalytic CO oxidation was studied on a Pt(110) single crystal and CeO2-supported mass-selected Pt200 clusters. The results demonstrate distinct reactivity trends, activation temperatures, and hysteresis behavior, highlighting the reactor's functionality for detailed studies in model heterogeneous catalysis.