Recent studies confirm that the emerging bifunctional catalysts consisting of metal oxide and zeolites can directly convert syngas into high-quality gasoline,however,the formation mechanism of iso-paraffins and the di...Recent studies confirm that the emerging bifunctional catalysts consisting of metal oxide and zeolites can directly convert syngas into high-quality gasoline,however,the formation mechanism of iso-paraffins and the difference with the conventional FT/zeolite catalyst have not been investigated.Herein,three one-dimensional SAPO zeolites with diverse micropore sizes were synthesized and assembled with ZnAlO_(x)with spinel structure.It was found that ZnAlO_(x)/SAPO-41 and ZnAlO_(x)/SAPO-11 with medium micropore sizes favored the formation of C_(5)–C_(11)hydrocarbons with a high content of iso-paraffins.The characterizations pointed out that the formation of iso-paraffins over SAPO-11 followed a pore-mouth catalysis mechanism,which means the isomerization of linear hydrocarbons can only take place near the pore mouth region of zeolites.This mechanism only allows the formation of mono-branched iso-paraffins in the C_(5)–C_(11)range,which are less prone to be cracked than their di-branched isomers.A careful comparative analysis between ZnAlO_(x)/SAPO-11 and Co/H-meso-ZSM-5 was also made in terms of product distribution,activity,and stability.展开更多
文摘Recent studies confirm that the emerging bifunctional catalysts consisting of metal oxide and zeolites can directly convert syngas into high-quality gasoline,however,the formation mechanism of iso-paraffins and the difference with the conventional FT/zeolite catalyst have not been investigated.Herein,three one-dimensional SAPO zeolites with diverse micropore sizes were synthesized and assembled with ZnAlO_(x)with spinel structure.It was found that ZnAlO_(x)/SAPO-41 and ZnAlO_(x)/SAPO-11 with medium micropore sizes favored the formation of C_(5)–C_(11)hydrocarbons with a high content of iso-paraffins.The characterizations pointed out that the formation of iso-paraffins over SAPO-11 followed a pore-mouth catalysis mechanism,which means the isomerization of linear hydrocarbons can only take place near the pore mouth region of zeolites.This mechanism only allows the formation of mono-branched iso-paraffins in the C_(5)–C_(11)range,which are less prone to be cracked than their di-branched isomers.A careful comparative analysis between ZnAlO_(x)/SAPO-11 and Co/H-meso-ZSM-5 was also made in terms of product distribution,activity,and stability.
