Highly Dispersed PtCu Alloy Catalyst For Selective Oxidation Of Glycerol To Glyceric Acid

Glycerol is a high-producing by-product in the production of biodiesel.At present,the downstream industry of glycerol is insufficient resulting in serious overcapacity of glycerol.Therefore,it is of great significance to study the conversion of glycerol into other products with high added value.Glyceric acid obtained by selective oxidation of glycerol is an important intermediate in synthesizing physiological active substances and amino acids,and it has tremendous application potential.However,the catalytic oxidation of glycerol is very complex,involving selective oxidization of the primary or secondary hydroxyl group,the deep oxidation,and C-C bond cleavage.The conversion and selectivity of selective oxidation of glycerol to glyceric acid are both low so far,especially in base free condition.In this work,PtCu alloy catalysts with highly dispersed metal active site have been prepared by in situ calcination and reduction of CuZrOx metal oxide.Through modulating the geometric structure and electronic structure of PtCu in the catalyst,and the electronic structure between PtCu alloy and the support,the glycerol conversion and glyceric acid selectivity have been enhance in the base free reaction condition.The main research work is displayed as follows:1.Catalysts with PtCu alloy,single Pt and single Cu active center structures have been obtained.Among them,the highly dispersed PtCu alloy catalyst is prove to have better catalytic performance in the oxidation of glycerol to glyceric acid.The electronic structure of the metal center together with the electronic structure between the metal center and the carrier has been studied.The geometric structure of the metal active center was studied by the in-situ FTIR spectra of CO adsorption on different catalysts.The relationship between the structure and the catalytic performances has also been investigated in detail.2.The dispersity of Pt in the PtCu nanoparticles has been regulated through controlling the Pt loading in the in situ calcination and reduction procedures.With the increment of Pt loading,the electronic cloud density of Pt increases,thus leading to intensified adsorption of glycerol on the surface.When the Pt loading is about 2.6%,a glycerol conversion of 75.3%and a glyceric acid selectivity of 82.5%have been achieved.3.The kinetic behavior of on PtCu alloy catalysts in the selective oxidation of glycerol to glyceric acid at different reaction temperature has been studied in detail.The glycerol conversion and the product distribution are quite dependent on the reaction temperature.When the reaction temperature is set as 60?,highest glycerol conversion and glyceric acid selectivity have been obtained with a calculated Ea value of 5.39 KJ/mol.