Transformation of syngas to light hydrocarbons over bifunctional CuO–ZnO/SAPO-34 catalysts: the effect of preparation methods

Abstract

Two series of bifunctional catalysts CuO–ZnO/SAPO-34 were prepared by isometric impregnation and milling calcination. The catalyst samples with different composition ratios have been investigated in the direct transformation of syngas to light hydrocarbons. Furthermore, all the samples were characterized by SEM, XRD, BET, H₂-TPR and NH₃-TPD techniques. The catalytic reactions were conducted with a feeding gas mixture of CO and H₂ at 320 °C and 3.0 MPa. The results indicate that the preparation methods have significant effect on the catalysts performance. Though both series of catalysts could realize the direct transformation and the catalysts prepared by the milling calcination method facilitated a little more syngas to convert, the catalysts prepared by the impregnation method led to higher light hydrocarbons selectivity and less unexpected byproduct like CO₂, since these serious catalysts displayed a smaller amount of metallic solid solution, a stronger interaction between the loaded metallic particles and supportive zeolites, more appropriate acidity strength as well.