The aim of the proposal is to use high-energy X-Ray diffraction (HEXRD) to study the structure of Pt/Al2O3 catalysts during the dehydrogenation reaction of the liquid organic hydrogen carrier (LOHC) benzyl-toluene. The studies will be carried out in a reactor mimicking an industrial application, under realistic conditions (300 °C, 1-5 bar). The goal of these measurements is to provide atomic-scale insights on the degradation processes of the catalyst during the reaction, that is, in operando conditions. Such knowledge is a prerequisite for the development of better and fully recyclable catalysts, making the LOHC hydrogen storage technology more competitive. We will study sulphidated and non-sulphidated catalysts to understand why sulphur poisoning improves catalytic activity and reduces the catalyst deactivation caused by carbonization.