Abstract:

The excessive emission of greenhouse gas CO₂ has caused global climate change. Catalytic conversion of CO₂via hydrogenation is a promising route for the achievement of carbon circular economy and carbon neutralization target. In this study, the bio-SAPO-34 with multiple meso- and macro- structures was synthesized by using rice husk as the bio-template. The hierarchical structure of bio-SAPO-34 facilitated the diffusion of reaction intermediates and improved the catalytic activity. The effect of synthesis parameters such as precursor concentration, structure-directing agent and the amount of rice husks on the replication the architecture of rice husks biotemplate have been systematically studied. Moreover, the ZnZrO _x was composited with bio-SAPO-34 to form ZnZrO _x &bio-SAPO-34 bifunctional catalyst for CO₂ hydrogenation to light olefins. Under reaction conditions of 380℃ and 3MPa, the selectivity of low olefins was 66.4% (in hydrocarbon products) with a CO₂ conversion of 11.8%. Furthermore, the obtained ZnZrO _x &bio-SAPO-34 bifunctional catalysts showed excellent stability in a 60h long-term test.

Key words: carbon dioxide, biotemplating, molecular sieves, catalysis, reduction

摘要：

CO₂过量排放导致全球气候异常，通过CO₂催化加氢将CO₂转化为具有高附加值的基础化学品或燃料是实现碳循环的有效方式，同时也有助于实现我国的“碳中和”目标。本文报道了基于稻谷壳前体制备具有多层次、相互贯通的介孔及大孔结构的bio-SAPO-34分子筛，该结构有利于反应过程中反应中间体的传质。本文系统地研究了分子筛前体液浓度、微孔导向剂种类及浓度、生物模板加入量等因素对bio-SAPO-34合成过程中维持生物模板分级结构的影响规律。将bio-SAPO-34与ZnZrO _x 固溶体氧化物组装构筑ZnZrO _x &bio-SAPO-34双功能催化剂用于催化CO₂加氢制备低碳烯烃反应。在380℃、3MPa的反应条件下，双功能催化剂的CO₂转化率为11.8%，低碳烯烃的选择性为66.4%（占烃类产物），且经过连续反应60h后未发现催化剂明显失活。

关键词: 二氧化碳, 生物模板, 分子筛, 催化, 还原