Supported Metal Nanoparticles‐Based Catalysts and their Interactions with H2: Insights from Inelastic Neutron Scattering Spectroscopy

The investigation of supported metal nanoparticle in the presence of H-2 is fundamental to better understand their behavior as hydrogenation catalysts. In this respect, this review will focus on the main recent results obtained by Inelastic Neutron Scattering (INS) spectroscopy, which is of particular interest thanks to its ability to provide very detailed vibrational spectra of the H-containing species in the sample. The review will cover the main results concerning the characterization of the H-species already present in the pristine catalyst, with a particular focus on carbon-based materials and their modification upon the interaction with metal nanoparticles. Successively, the forms in which H-2 interacts with the catalysts will be examined, starting from H-2 physisorption, to then pass to the metal hydride species formed through the splitting of dihydrogen upon the active metallic phase, and finally to the migration of atomic hydrogen from the metal nanoparticles onto the support as a result of hydrogen spillover. The aim of the review is to present an overview of all the hydrogenous species identifiable by INS spectroscopy in hydrogenation catalysts, focusing on the specific case of supported metal nanoparticles systems.