Direct synthesis of light olefins from syngas (STO) using a bifunctional catalyst composed of oxide and zeolite has attracted extensive attention in both academia and industry. It is highly desirable to develop robust catalysts that could enhance the CO conversion while simultaneously maintain high selectivity to C2-C4 olefins. Herein, we report a bifunctional catalyst consisting of ZnCr binary oxide (ZnCrO_x) and low-Si AlPO-18 zeolite, showing both satisfying selectivity to C2-C4 olefins of 45.0% (86.7%, CO₂ free) and high olefin/paraffin ratio of 29.9 at the CO conversion of 25.2% under mild reaction conditions (4.0 MPa, 390 °C). By optimizing the reaction conditions, the CO conversion could be markedly increased to 49.3% with a slight drop in selectivity. CD₃CN/CO-FTIR characterizations and theoretical calculations demonstrate that low-Si AlPO-18 zeolite has lower acid strength, and is therefore less reactive toward the hydride transfer in the STO reaction, leading to a higher olefin/paraffin ratio.

使用由氧化物和沸石组成的双官能催化剂由合成气（STO）直接合成轻烯烃已引起学术界和工业界的广泛关注。迫切需要开发出能够提高CO转化率，同时保持对C2-C4烯烃的高选择性的稳健催化剂。本文中，我们报告了一种由ZnCr二元氧化物（ZnCrO _x）和低硅AlPO-18沸石组成的双功能催化剂，显示出对45.0％（86.7％，不含CO ₂）的C2-C4烯烃和高烯烃/石蜡的选择性都令人满意。在温和的反应条件（4.0 MPa，390°C）下，当CO转化率为25.2％时，CO 2的摩尔比为29.9。通过优化反应条件，可以将CO转化率显着提高至49.3％，而选择性略有下降。CD ₃CN / CO-FTIR表征和理论计算表明，低硅AlPO-18沸石具有较低的酸强度，因此在STO反应中对氢化物转移的反应性较小，从而导致较高的烯烃/石蜡比。