PreparationofCo–MgOmixedoxidenanocatalysts for lowtemperatureCOoxidation:Optimizationof preparationconditions

چکیده مقاله

In thisstudy,aseriesofCo–MgOmixedoxides(30wt.%Co)werepreparedbyco-precipitationmethodandemployed as catalystinlowtemperatureCOoxidationreaction.ThepreparationconditionswereoptimizedbytheTaguchi method ofexperimentaldesigntosynthesizeasamplewithhighcatalyticperformancetowardCOoxidationreac- tion. Theeffectsoffourvariables,pHofsolution,agingtemperature,agingtimeandmolarityofprecursorsolution at threelevelswereinvestigated.TheoptimizedsamplewascharacterizedbyX-raydiffraction(XRD),temperature programmedreduction(TPR),temperatureprogrammeddesorptionofoxygen(O2-TPD), N2 adsorption/desorption, thermal gravimetricanddifferentialthermalanalysis(TGA/DTA),andtransmissionelectronmicroscopy(TEM)tech- niques. Theresultsrevealedthattheoptimizedsampleshowedamesoporousstructurewithanarrowporesize distribution centeredintherangeof7–17nmandparticlesizeabout5.5nm.Itwasfoundthatthemolarityofsolu- tion andagingtimehadthemostinfluenceontheCOconversion,respectively.Thecatalyticresultsshowedthat the highestCOconversionobtainedfromsamplessynthesizedbyTaguchiorthogonalarraywasabout90%at200 ◦C, while theCOconversionforoptimizedsamplewas95%.Inaddition,theeffectofoperationalconditionswasstudied overoptimizedsample.