BESSY II: New sample environment allows glimpse into thermocatalytic processes
A schematic diagram of the measuring cell: it enables the x-ray analysis of catalytic reactions under high pressure and high temperature. © HZB
A novel measurement cell allows, for the first time, soft and hard X-ray investigations under high pressures of up to 20 bar and temperatures of up to 400°C. This provides new insights into thermocatalytic processes, such as the Fischer-Tropsch synthesis for producing synthetic fuels. The development of the measurement cell is considered a significant achievement within the Care-O-Sene project.
The innovative measurement cell enables in-situ/operando X-ray absorption spectroscopy (XAS) measurements under high pressures and temperatures for the first time. The cell is suitable for use in both the soft and the tender/hard X-ray energy ranges and was designed for the ‘Operando Absorption and Emission Spectroscopy’ (OÆSE) endstation in the Energy materials In-situ Laboratory Berlin (EMIL) at the BESSY II synchrotron facility. The setup enables the investigation of catalytic gas-solid reactions under high pressure in realistic operating conditions of up to 20 bar and up to 400°C. “Many industrially important catalytic reactions take place under such conditions, for example the Fischer-Tropsch synthesis, which is used worldwide to produce hydrocarbons,” says Dr. Athanasios Skaltsogiannis, postdoc in the Care-O-Sene project working in the team of Prof. Marcus Bär.
Dr. Catalina Jimenez, who scientifically coordinates the Care-O-Sene activities at HZB, emphasizes: “This development is a significant milestone, particularly for soft X-rays, as soft X-rays are significantly more attenuated in solids and highly pressurized gases than tender/hard X-rays.” As a result, soft X-ray absorption spectroscopy (XAS) studies have so far been limited to be performed at atmospheric (or slightly higher) pressures. However, XAS measurements using soft X-rays offer detailed insights into the chemical and electronic properties of samples containing elements such as carbon, nitrogen, and oxygen, or transition metals.
In the journal ACS Photon Science, the team, which also involved colleagues from the sample environment group of the HZB and from the chair of Chemical Technology and Catalysis at KIT, describes the design of the new sample environment and demonstrates its operation with the measurement of the redox reaction of a Co/Mn thin film. With this newly developed measurement cell it is now possible to investigate many industrially relevant catalytic processes under realistic conditions.
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