Structure Control Of Cmposite Metal Oxides And Catalytic Performance With Supported Metal

With the sustainable development of economy and energy,the production of renewable biomass fuels and chemicals can feed the demand for energy,which is a good way to reduce environmental pollution.There are many opportunities for the development of biomass and biofuels.Biodiesel is a green product of biorefinery technology that can effectively meet the energy needs of economic development.Glycerol,which contains multiple functional groups,is a by-product in the preparation of biodiesel and one of the bio-platform molecules.There is currently a large excess of glycerol production,and it is necessary to propose new methods to convert glycerol into other value-added products.Oxidation of glycerol is a simple chemical conversion process that provides aldehydes,ketones,acids and polyols with small molecular.It is an efficient way to utilize glycerol.The path of glycerol oxidation is complex including C3 products such as glyceric acid,tartronic acid and DHA.Deep oxidation will break the C-C bonds to produce C2(glycolic acid and oxalic acid)and C1 products(formic acid C02 gas).The reaction conditions and catalysts have great influence on the conversion and selectivity of glycerol oxidation,which is a hot research topic at present.Suitable oxidation ability can not only effectively oxidize hydroxyl groups to obtain higher conversion,but also make the reaction stay at a specific stage,with good selectivity for specific products and fewer by-products.In order to improve the efficiency of glycerol oxidation,spinel was used as the carrier to synthesize complex metal oxides by adding alkali metal Ca and transition metal Cu,which provided various functional sites for glycerol oxidation.The effect of reaction conditions on catalytic oxidation was explored.(1)Calcium-zinc-aluminum spinel was synthesized by hydrothermal method.Pt nanoparticles were supported on the surface of spinel by NaBH4 reduction method.The prepared catalyst Pt/ZCA-x was used for glycerol oxidation under base-free conditions.With the introduction of Ca,the structure of the spinel can still be maintained,and the medium-strong basic sites increased greatly,which improves the conversion of glycerol oxidation.Ca has an adsorption and electron transport effect on Pt.This synergistic effect enhances the ability of Pt to dissociate oxygen and further catalytic effect.With 10%of Ca incorporation,the catalyst has the best glycerol oxidation performance.The conversion of glycerol is 61.75%,and the selectivity to glyceric acid is 81.05%.The catalyst has great ability of glycerol oxidation under mild conditions.(2)The CuZnAl-spinel was synthesized by hydrothermal and impregnation method.After calcination,Cu2+ enters into the crystal lattice.The diameter of the spinel nano-particles is about 10 nm with good crystallinity,which can be used for catalytic oxidation of glycerol.Cu2+ has strong ability of C-C bond cleavage to produce acid with small molecular.With the reaction temperature of 60?,the conversion to glycerol is 52%on ZAC-10,and the selectivity of C1 product formic acid can reach 42%.CuZnAl-spinel,with regular structure,strong resistance of acid and base conditons,can maintain great ability for glycerol oxidation after reuse.