Study on distribution of CO hydrogenation products regulated by surface-modified Fe/CS
The preparation of high value-added chemicals via CO hydrogenation with Fischer-Tropsch synthesis is one of the important ways to achieve clean and efficient utilization of coal.The development of efficient catalysts is the key to achieve targeted regulation of product distributions,improve the selectivity of target products and inhibit the formation of C1 by-products.The surface properties of catalysts have a significant impact on the adsorption and activation of CO,hydrogenation activation and product distributions.Anhydrous glucose was used as the carbon source and ethylene glycol was used as the solvent to prepare the carbon support by solvothermal method.After H2O2and NH3·H2O surface modification and nitrogen doping,5Fe/CS-H2O2,5Fe/CS-NH3·H2O and 5Fe/CS-N catalysts were prepared by impregnation method,respectively.The effect of surface modification on the product distributions of Fischer-Tropsch synthesis was investigated.The samples were characterized by XRD,SEM,TEM,N2 adsorption/desorption,TG-DTG,FT-IR,Zeta potential,XPS and Raman.The results show that different surface modification methods have a significant impact on the surface physicochemical properties and catalytic performances of catalysts.The modification of H2O2 increases the amount of—OH on catalyst surface,enhances the hydrophilicity of catalyst surface,promotes the dispersion of Fe on the support,and improves the thermal stability of catalysts.The activity test of CO hydrogenation reaction was conducted under the conditions of 300 ℃,1.5 MPa,space velocity 1000 h-1 and n(H2)∶n(CO)=2.The results show that the modified catalysts significantly inhibit the generation of CH4 and improve the selectivity of light olefins.The olefin selectivities of 5Fe/CS-NH3·H2O,5Fe/CS-N and 5Fe/CS-H2O2 increase from 24.39％to 34.94％,37.63％and 43.57％,respectively.The surface properties of the catalyst are adjusted by surface modification and nitrogen-doping treatment,and the product distribution is optimized.
CO hydrogenationFe/CS catalystssurface modificationlight olefins
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