Direct conversion of syngas to light olefins using bifunctional catalysts containing both oxides and zeolites represents a promising alternative in comparison with Fischer-Tropsch synthesis. It is still a great challenge to achieve highly selective production of ethylene and propylene at a satisfying CO conversion for potentially industrial applications. Here, we report that a high selectivity to ethylene and propylene can be achieved by tailoring silicoaluminophosphate zeolite structure and acid site strength. By comparing bifunctional catalysts composed of ZnCr oxide and different zeolites with 8-membered ring openings, we achieve the total selectivity of 76.4% in ethylene and propylene at a CO conversion as high as 38.2% by catalysts containing SAPO-17 zeolite (ERI framework). The detailed hydrocarbon distribution is nearly identical to that in the methanol-to-olefins reaction. The high selectivity can be rationalized due to both smaller 8-membered ring openings and the weaker Brønsted acid strength of SAPO-17 zeolites.

与费-托合成法相比，使用同时包含氧化物和沸石的双官能催化剂将合成气直接转化为轻质烯烃代表了一种有前途的选择。在令人满意的CO转化率下实现高选择性生产乙烯和丙烯以进行潜在的工业应用仍然是一个巨大的挑战。在这里，我们报告说，可以通过调整硅铝磷酸盐分子筛结构和酸位强度来实现对乙烯和丙烯的高选择性。通过比较由ZnCr氧化物和具有8元开环的不同沸石组成的双功能催化剂，使用含SAPO-17沸石（ERI骨架）的催化剂，在CO和转化率高达38.2％的情况下，乙烯和丙烯的总选择性达到76.4％。 。详细的烃分布几乎与甲醇制烯烃反应中的相同。由于较小的8元环开口和SAPO-17沸石的布朗斯台德酸强度较弱，因此可以使高选择性合理化。