In situ investigations of chemical reactions on surfaces by X-ray diffraction at atmospheric pressures

Catalytic reactions occurring at metal surfaces and nanoparticles have been an established research field for decades, yielding information on adsorption sites and reaction pathways under ultrahigh-vacuum conditions. Recent experimental developments have made it possible to perform well-controlled in situ surface x-ray diffraction measurements from single-crystal surfaces and nanoparticles under industrially relevant conditions. In this way, a new understanding of atomic-scale processes at surfaces and nanoparticles occurring during catalytic reactions under realistic conditions has been gained. In particular, the identification of the formation of thin oxides on model catalysts and their role in oxidation reactions demonstrates the importance of in situ probes under relevant conditions.