High-pressure soft X-ray absorption spectroscopy: application of a new in situ spectroscopic method in catalysis research

In situ investigations under real reaction conditions are necessary since the structure of catalysts can be very different from that found post mortem or ex situ. The object of this research was to demonstrate the use of an X-ray absorption spectroscopy (XAS) detector system that is suitable for in situ investigations in the soft X-ray range of 250≤hν≤1000 eV under gas/solid reaction conditions close to those used in practice. As an example, the conversion reaction of methanol over copper catalysts is studied under reaction conditions (T≥500 K, p≥0.5 mbar). A novel atomic oxygen species is found under reaction conditions characterized by chemical functionality that is significantly different from copper oxide surfaces found in the ex situ spectroscopic analysis which contain oxygen atoms interacting strongly with copper 3d states