Ce改性Ni/SAPO-11催化剂对烃基生物柴油制备的影响OA

Self-synthesized SAPO-11 molecular sieve was used as the carrier and Ce(NO3)3 as the Ce source to prepare a series of Ni-xCe/SAPO-11 catalysts with different Ce loadings(the mass fraction of Ce element in the total catalyst mass,1％-7％)by the incipient wetness impregnation method.The catalysts were characterized by various techniques,and their catalytic performance and cyclic stability were evaluated for the one-step hydro-deoxygenation and isomerization of fatty acid methyl ester(FAME)to produce hydrocarbon-based biodiesel.The results indicated that the introduction of Ce increased the specific surface area of the catalyst,enhanced the surface basic sites and improved the dispersion of Ni active sites,without reducing the acid strength and destroying the molecular sieve configuration.Among the catalysts,Ni-5Ce/SAPO-11 exhibited a specific surface area of 173 m2/g and a pore volume of 0.13 cm3/g,indicating a clear pore-expansion effect,whereas excessive Ce loading would lead to a decrease in specific surface area.The optimal performance was observed over Ni-5Ce/SAPO-11 at 300 ℃ for 4 h,giving 100％FAME conversion,98.4％C15-C18 alkane selectivity and a 24.9％isomerization rate.Furthermore,the addition of Ce improved the cyclic stability of the catalyst,and the selectivity to long-chain alkanes(C15-C18)over Ni-7Ce/SAPO-11 remained as high as 83.4％after four reaction cycles.