Set-up of a novel Electrochemical IR Spectroscopy Apparatus with Liquid/Solid-Interface-Preparation: ELISA I&II

Pt-doped CeO2 has been identified as a potential anode electrocatalyst in proton exchange membrane fuel cells (PEMFC). Providing very high noble metal efficiency, the material may help to decrease the demand for Pt, while simultaneously increasing the tolerance against CO poisoning. To investigate complex model catalysts’ surfaces on single crystals under ultraclean conditions the latter must be prepared in the ultrahigh vacuum (UHV). To this end we present a UHV system that allows preparation and characterization of model electrocatalysts and subsequent transfer to an electrochemical cell without contact to ambient atmosphere. The system is equipped with all standard preparations tools, electron beam evaporators, thermal evaporator cells and a quartz microbalance. Structural and chemical analysis is possible by low energy electron diffraction (LEED), Auger electron spectroscopy (AES) and temperature programmed desorption (TPD). The sample single crystal is transferred through a differentially pumped stage into the electrolyte without breaking the UHV in the preparation system. Contamination-free transfer of the prepared single crystal samples are characterized by cyclic voltammetry (CV). To explore the chemical state of the Pt species in the ceria matrix under reaction conditions we apply insitu electrochemical IR spectroscopy. Towards this aim we have set up a new IR spectroelectrochemistry system that includes a state-of-the-art vacuum FTIR spectrometer and an optimized external reflection cell. We demonstrate that the system is functional and provides an excellent signal/noise ratio.