The soot combustion process promoted by some of the most promising diesel particulate combustion catalysts (Cs2O·V2O5, Cs4V2O7, CsVO3) is discussed on the grounds of a theoretical analysis and an experimental test campaign involving reaction runs in microreactors (either in isothermal or in temperature-programmed conditions) and in a DSC apparatus. Such investigations, beyond the prevalent kinetic parameters (activation energy, oxygen reaction order, preexponential kinetic constant), led to a definition of the role of catalyst-to-carbon contact conditions on the conversion rate. Particularly, the role of formation of eutectic liquid phases, which dominates the catalytic behavior of the Cs2O·V2O5 catalyst, was fully elucidated on the grounds of either DSC runs or visual inspection through a heated optical microscope.