关键词: 合成气, 二氧化碳, 加氢, 费托合成, 分子筛

Abstract:

Carbon monoxide/carbon dioxide (CO/CO₂) utilization，as the central part of C1 chemistry and carbon capture and utilization，becomes one of the most severe challenges for human society nowadays. For CO₂ utilization，it is very important to achieve CO₂ activation and C—C precise coupling simultaneously. It is a great challenge to control C—O activation，C—C coupling carbon chain growth and termination effectively for syngas conversion. We provide an overview of the significant breakthrough on CO/CO₂ hydrogenation to lower olefins (C₂ ⁼—C₄ ⁼)，which are widely used in the chemical industry and direct CO₂ hydrogenation to gasoline-range hydrocarbons (C₅—C₁₁) with high selectivity. Currently，Fischer-Tropsch (FT) synthesis and oxide/zeolite bifunctional catalysis routes can be utilized to produce lower olefins or gasoline fuels directly from CO/CO₂ hydrogenation. For FT to C₂ ⁼—C₄ ⁼，the product distribution over cobalt carbide nanoprisms deviates markedly from the classical Anderson-Schulz-Flory (ASF) distribution. In addition，acidic zeolites have been exploited to construct the bifunctional FT catalyst，and CO/CO₂ can be directly transformed into C₅—C₁₁ hydrocarbons with good selectivity owing to the catalytic function of acidic zeolite in the hydrocracking/oligomerization/isomerization reactions. On the other hand，the integration of the reduced oxide，which is responsible for the activation of CO or CO₂ to methanol，and SAPO-34 or HZSM-5 zeolite responsible for the selective C—C coupling can also realize the direct synthesis of lower olefins or gasolines from CO/CO₂ hydrogenation with excellent selectivity at a high conversion. In the future，the main objective is to maximize the selectivity of the target hydrocarbons and to reduce methane production significantly by adopting new methods in nano-synthetic areas which deviates from the classical ASF distribution.

Key words: syngas, carbon dioxide, hydrogenation, Fischer-Tropsch synthesis, moleclar sieves