PM-IRAS/XPS/HP-Cell Chamber

Picture of a XPS/PM-IRAS Setup

© AG Rupprechter

Its main purpose is model catalyst preparation and characterisation and to investigate their properties for heterogeneous catalysis. The setup is custom build, with a high pressure cell for Polarisation Modulation Infrared Reflectance Absorption Spectroscopy (PM-IRAS) measurements (pressure range 10-9 mbar – 1000 mbar) to bridge the prominent gap between UHV and ambient conditions (“pressure gap”). It includes a UHV preparation chamber for sample preparation and characterisation with LEED, XPS, AUGER and TPD. The system is also equipped with gas dosing units and PVD evaporators. After preparation samples can be transferred to the high pressure cell. The cell is designed as circulating batch reactor. At catalytic reactions conditions adsorbed species can be identified on the model catalyst surface. Due to a special sample holder and mounting design we can operate in the temperature range 77 – 1200 K.


Photo of a XPS/HT-STM Setup in Prof. Rupprechters lab

© AG Rupprechter

The system is an extended STM setup from SPECS (Germany) with 3 chambers for STM, sample preparation and a load lock for fast sample transfer into and out of UHV. The preparation chamber is equipped with LEED, TPD, hemispherical analyser and instruments for XPS, AUGER and LEIS measurements. Furthermore the system is equipped with gas dosing units and PVD evaporators. The setup is dedicated to model catalyst preparation and characterisation in UHV.

SFG/AES/HP-Cell Chamber

SFG_setup "DAISI" with laser optics and UHV + spectroscopic cell

© AG Rupprechter

The setup is dedicated to model catalysts preparation and characterisation, from single crystals up to supported nanoparticles, and to study their interaction with reactive gases. The setup is comprised of three parts: a UHV preparation chamber, a load lock for fast sample transfer and a spectroscopic cell for investigations under realistic catalytic conditions. The preparation chamber is equipped with the standard tools of surface science: an ion gun, gas dosing, PVD evaporator, mass spectrometer (for TPD) and LEED + Auger optics. Samples can be transferred without breaking the vacuum to the spectroscopic cell which allows to perform SFG (sum frequency generation) spectroscopy under reaction conditions. The cell is designed as circulating batch reactor with the possibility of gas analysis via MS. SFG probes vibrationally the sample in the 1000-4500 cm-1 range and provides inherently surface specific information about the species adsorbed on the specimen. Therefore it can be applied from UHV to ambient pressure and bridges the well-known gap between the classical UHV studies and real catalysis.

Flow Microreactor

Photograph of a microreactor

© AG Rupprechter

In heterogeneous catalysis it is of high interest to investigate how single or polycrystalline model catalysts, whose surfaces have already been prepared and characterised, behave under reaction conditions (i.e. elevated pressure and temperature). This behaviour is reflected by kinetic parameters such as conversion, yield, catalytic productivity and selectivity. Commercially available systems feature reaction volumes which surpass the catalytically active surface area of model catalysts by orders of magnitude, thus lowering the detection sensitivity of reaction gases tremendously. To solve this problem a new system for both catalyst preparation under UHV and performance of reactions on the catalyst’s surface (up to 1 bar) within a dense, dismountable micro reactor was developed. The small cell volume (i.e. cell in cell design) of the continuous flow reactor allows excellent catalytic characterisation of model catalysts.  


Photo of a PEEM surface analysis system

This multipurpose UHV surface analysis system is dedicated to in situ/operando surface microscopy directly watching reactants during ongoing surface reactions. It consists of two independent UHV chambers: a PEEM-chamber with differential pumping (allowing in situ studies at reactants pressure up to 10-4 mbar; high-speed video-camera) including sample preparation facilities, LEED, MS, AES, gas supply, and an XPS-chamber with hemispherical electron energy analyzer (SPECS) again including sample preparation facilities and gas supply. Both chambers are connected by a sample transfer line, enabling to move a sample between the chambers in UHV.

FIM/FEM Chamber

Photo of a FEM surface analysis system

This multipurpose UHV surface analysis system is dedicated to in situ/operando surface microscopy of reactions on nanotips or curved crystals, enabling single particle catalysis. The UHV chamber containing the FIM/FEM microscopes is equipped with gas supply for reactive (CO, H2, O2) and noble (He, Ne, both for FIM imaging) gases, and upgraded by a novel, recently developed temperature control system based on wireless data transmission between the control panel and the high-voltage facilities. A high-speed video-camera (Hamamatsu) allows in situ monitoring with up to 500 frames/s of processes visualized by FIM/FEM. A mini-mass spectrometer can be inserted into the FIM (inset), so that local reaction products can be chemically identified on atomic scale via the magnetically modified trajectories of particular ions, modifying/shifting the FIM image.