It　has　been　generally　accepted　that　active　oxygen　generation　capability　and　wetting　effect　of　catalyst　have　a　significant　influence　on　catalytic　soot　oxidation　with　O2.　Thus,　these　two　factors　were　investigated　for　low　Tammann　temperature　Ru-based　materials　in　soot　oxidation　reaction,　with　Pt/Al2O3　as　a　reference　catalyst.　The　catalysts　were　characterized　by　O2　temperature-programmed　desorption　(O2-TPD),　soot　temperature-programmed　reduction　(soot-TPR)　and　environmental　transmission　electron　microscope　(ETEM),　cycled　H2　temperature-programmed　reduction　(cycled-TPR),　cyclic　thermogravimetric　analysis　(cyclic　TG),　in-situ　X-ray　Diffraction　(in-situ　XRD),　et　al.　Based　on　the　soot　temperature-programmed　oxidation　(soot-TPO)　and　kinetic　studies,　Ru/Al2O3　demonstrates　a　much　better　catalytic　activity　than　Pt/Al2O3.　ETEM　images　indicates　further　RuO2　particles　do　not　move　during　soot　oxidation　and　hereby　wetting　effect　does　not　play　a　critical　role.　The　O2-TPD　and　soot-TPR　results　indicate　that　Ru/Al2O3　exhibits　superior　oxygen　dissociating　ability　and　possesses　more　active　oxygen　species　compared　with　Pt/Al2O3.　The　cycled-TPR　and　cyclic-TG　findings　further　confirm　the　excellent　regeneration　ability　of　active　oxygen　species　on　Ru/Al2O3　which　arises　importantly　from　the　release　of　lattice　oxygen　in　RuO2　and　refilling　of　oxygen　vacancies　with　gaseous　oxygen.　Such　superior　oxygen　activation　and　regeneration　ability　even　reverse　the　contacting　trend　of　the　solid–solid-gas　reaction.　Surprisingly,　high　activity　is　achieved　over　this　catalyst　under　loose　contact　conditions　in　comparison　with　the　tight　contact　case,　which　depends　on　competition　between　O2　transfer　and　O2　activation.　©　2024