The formation of a PdZn alloy from a 4.3% Pd/ZnO catalyst was characterized by combined in situ high-resolution X-ray diffraction (HRXRD) and X-ray absorption spectroscopy (XAS). Alloy formation started already at around 100 °C, likely at the surface, and reached the bulk with increasing temperature. The structure of the catalyst was close to the bulk value of a 1:1 PdZn alloy with a L1 o structure (R PdÀPd = 2.9 Å, R PdÀZn = 2.6 Å, CN PdÀZn = 8, CN PdÀPd = 4) after reduction at 300 °C and above. The activity of the gas-phase hydrogenation of 1-pentyne decreased with the formation of the PdZn alloy. In contrast to Pd/SiO 2 , no full hydrogenation occurred over Pd/ZnO. Over time, only slight decomposition of the alloy occurred under reaction conditions.

In this short review, we describe the complementary experimental capabilities for catalysis research at two beam lines available to the Swiss community, SuperXAS at SLS (Swiss Light Source, Villigen) and SNBL (Swiss Norwegian Beam lines) at ESRF (European Synchrotron Radiation Facility, Grenoble). Over the years, these two facilities have been developed to provide powerful techniques for structural studies under in situ and operando conditions. These techniques, X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), and X-ray emission spectroscopy (XES) in combination with Raman or infrared spectroscopy provide new avenues for structure-performance studies of catalysts. Several exemplary studies are used to demonstrate the capability of these facilities.