Study On Catalytic Oxidative Coupling In Situ Hydrogenation Ultra-deep Desulfurization Catalyst

Sulfur oxides（SO_x）and sulphate particulate matter（SPM）from fuel combustion are significant sources of acid rain and air pollution,so governments around the world are implementing new regulations aimed at reducing sulfur levels in gasoline and diesel.In order to achieve the goal of C-S bonds in highly selective fracture sulfur compounds without reducing fuel yield,in this paper,bimetalically doped cerium dioxide nanorods and aluminum-bridged mesoporous silica core-shell nanomaterials were used as highly selective catalysts for catalytic oxidation-coupled in-situ hydrodesulfurization,and ultra-deep desulfurization was achieved by using the synergistic effect between the bimetallic active center and the carrier to provide catalytic oxidation and in situ hydrogenation reaction active sites.Firstly,the improved hydrothermal method was used to prepare Cd/Ni@Ce O₂nanorod materials as catalytic oxidation coupled in-situ hydrogenation ultra-deep desulfurization catalysts under visible light irradiation,and characterized by TEM,XRD,XPS,Roman,FTIR,UV-vis and BET.The results showed that mesoporous nanorods with uniform size（length:100-200nm,width:30-40nm）and different oxygen vacancies were obtained with bimetals doped with cerium dioxide.The co-doping of Cd/Ni not only expanded the absorption range of visible light,promoted the effective separation of electron-hole pairs,but also increased the number of trivalent cerium ions and oxygen vacancy defects.The effects of Cd/Ni doping amount,doping ratio,catalyst type,catalyst dosage and reaction temperature on 4,6-DMDBT desulfurization were explored.Under visible light irradiation,the reaction time was 50 min,the desulfurization rate of 20%Cd/Ni@Ce O₂reached 100%,and the catalytic activity of the catalyst was slightly reduced after 10 reuses,but it was negligible,indicating that 20%Cd/Ni@Ce O₂had excellent desulfurization catalytic activity and good stability,which was mainly due to the synergistic effect between Cd/Ni and Ce O₂to facilitated the fracture of Carbon-sulfur bonds.Secondly,Ce/Cd was deposited on the surface of Si O₂core-shell material by sol-gel method and co-precipitation method to prepare Al-Si O₂@Ce/Cd desulfurization catalyst,and characterized and analyzed by STEM-EDX,XRD,XPS,FT-IR,N2 adsorption-desorption and other means,the results showed that Ce/Cd was evenly distributed on the surface of mesoporous Si O₂core-shell material,and the loading of bimetals helped to increase the specific surface area of Si O₂core-shell material,thereby anchoring more effective metal active sites.The desulfurization experiments showed that Al-Si O₂@Ce/Cd showed excellent catalytic activity for 4,6-DMDBT under mild conditions,when the total Doping of Ce/Cd was 20%（1:1）,which was consistent with the calculation of apparent activation energy,because the synergistic effect between the active site of Ce/Cd and the Si O₂core shell was conducive to promoting oxidation and hydrogenation reactions.Al species bridging on Si O₂hydroxyl groups enhanced the interaction between metal and support（MSI）while increasing the acidity of the catalyst.The mesoporous channel had good accessibility,and sulfur-containing compounds could effectively diffuse in and out of mesoporous silica materials to improve mass transfer capacity.The core-shell structure also provided a nano-confined environment for the removal of 4,6-DMDBT,which improved the reaction microenvironment of catalyst and sulfide,thereby further improving the selectivity of desulfurization catalyst.