High-Pressure Soft X-Ray Absorption Spectroscopy: A Contribution to Overcoming the “Pressure Gap” in the Study of Heterogeneous Catalytic Processes

For the first time an active surface phase was characterized by means of surface-sensitive X-ray absorption in the soft X-ray region—the oxidation of methanol on copper under practicle conditions was used as an example—and its function was correlated with the catalytic activity of the system. This phase is not merely oxygen absorbed onto the surface (left picture, O=black spheres), but rather a copper suboxide which is formed in the region near the surface (right picture).