Au/CuxCey催化甘油氧化制二羟基丙酮的性能及失活机制研究OA

The development of biodiesel had caused a serious surplus of glycerol production.It was of great significance to explore the catalytic technology for the conversion of glycerol into high value-added chemicals.In this study,a series of Au/CuxCey catalysts with different n(Cu)∶n(Ce)ratios were prepared and their catalytic performance for selective oxidation of glycerol to dihydroxyacetone(DHA)in a non-alkaline medium was systematically evaluated.By means of X-ray diffraction(XRD),transmission electron microscope(TEM),X-ray photoelectron spectroscopy(XPS),carbon dioxide temperature programmed desorption(CO2-TPD)and hydrogen temperature-programmed reduction(H2-TPR),the effects of n(Cu)∶n(Ce)on Au0 content.Au particle size,redox properties,surface basicity and glycerol conversion activity of the carrier were clarified.Among them,the catalyst Au/Cu9 Ce1 prepared at n(Cu)∶n(Ce)=9∶1 catalyzed the glycerol oxidation reaction under the mild conditions of low Au loading(1.2%),60℃and PO2=0.5 MP a.The glycerol conversion rate was as high as 86.7%,and the DHA selectivity was73.4%.In addition,the stability test of the catalyst Au/Cu9 Ce1 revealed a significant decline after five times of reaction.The combined characterization results indicated that the catalyst's deactivation was mainly due to two aspects:firstly,the surface area carbon,which covered the active sites and hindered the contact of reactants as well as reduced the catalytic efficiency;secondly,the significant decrease in the lattice oxygen content weakened the catalyst's redox ability,resulting in a substantial drop in reaction activity.