A　series　of　ceria　(CeO2)　modified　MgAl2O4　spinels　were　used　to　support　silver　nanoparticles　(Ag/MgAl2O4-Ce)　and　tested　for　catalytic　soot　oxidation.　This　solid　composition　presents　outstanding　catalytic　activity　for　soot　oxidation,　namely,　initial　reaction　temperature,　T-i　=　236　degrees　C,　and　temperature　of　maximum　reaction　rate,　T-m　=　359　degrees　C.　In　contrast　to　Ag/MgAl2O4,　the　presence　of　CeO2　enhanced　significantly　the　formation　of　superoxide　and　peroxide　surface　adsorbed　oxygen　species,　thereby　largely　promoting　the　catalytic　performance　in　soot　oxidation.　Induced　by　the　strong　interactions　between　Ag　and　CeO2,　Ag/MgAl2O4-Ce　displays　higher　Ag　metal　dispersion　with　excellent　thermal　stability　than　Ag/MgAl2O4　catalyst.　This　explains　well　the　absence　of　deactivation　for　the　Ag/MgAl2O4-Ce　catalyst　after　five　cycles　of　soot　combustion.