We propose to study the H2- and CO-induced structural reconstruction of Ru nanoparticles (NPs) in Ru/Al2O3 catalysts by time-resolved XRD/PDF experiments under gas- and liquid-phase conditions. Preliminary gas-phase experiments (CH-6371) showed restructuring of Ru NPs during H2 activation, and literature reports ample evidence of CO-induced oxidative disruption of small Ru clusters, responsible for an increase in metal dispersion but potentially deactivating the catalyst. Yet, a comprehensive description of adsorbate-induced structural change within Ru catalysts is lacking. Although important for industrial applications, restructuring processes are much less explored in the liquid phase. These results will further inform on the comparison of gas-phase and liquid-phase conditions and cover the structural dynamics and kinetics of Ru NPs during the key stages of Ru-hydride formation and CO-induced oxidative disruption.