A　single　metal　Pd-Ce/gamma-Al2O3　catalyst　and　a　bimetallic　Pd-Ce/gamma-Al2O3　catalyst　were　prepared　by　the　equal-volume　impregnation　method　to　investigate　the　effect　of　CeO2　loading　on　the　catalytic　oxidation　of　toluene.　The　specific　surface　area,　surface　morphology,　and　redox　performance　of　the　catalyst　were　characterized　by　N-2　desorption,　scanning　electron　microscope　(SEM),　transmission　electron　microscope　(TEM),　X-ray　photoelectron　spectroscopy　(XPS),　H-2-TPR,　O-2-TPD,　and　electron　paramagnetic　resonance　(EPR).　The　results　showed　that　bimetal　catalysts　loaded　CeO2　had　smaller　nano-PdO　particles　than　those　of　the　Pd-Ce/gamma-Al2O3　catalyst.　Compared　with　the　catalyst　of　0.2Pd-Ce/gamma-Al2O3　(percentage　of　mass,　the　same　as　below),　the　catalyst　doped　with　0.3CeO(2)　had　a　stronger　reduction　peak,　which　was　shifted　to　the　lowtemperature　zone　by　more　than　80　degrees　C.　The　results　of　XPS　and　O-2-TPD　showed　that　the　introduction　of　CeO2　provided　more　surface　oxygen　vacancy　for　the　catalyst　and　enhanced　its　catalytic　oxidation　ability,　and　the　amount　of　desorbed　O-2　increased　from　3.55　mu　mol/g　to　8.54　mu　mol/g.　The　results　of　EPR　were　that　the　addition　of　CeO2　increased　the　content　of　active　oxygen　species　and　oxygen　vacancies　on　the　surface　of　the　catalysts,　which　might　be　due　to　the　supply　of　electrons　to　the　O-2　and　PdO　during　the　Ce(3+)to　Ce4+　conversion　process.　That　could　have　accelerated　the　catalytic　reaction　process.　Compared　with　the　single　precious　metal　catalyst,　the　T-10　and　T-90　of　the　Pd-Ce/gamma-Al2O3　catalyst　were　decreased　by　22　degrees　C　and　40　degrees　C,　respectively.　(C)　2020　Elsevier　Ltd.　All　rights　reserved.