Direct CO₂ hydrogenation into linear α-olefins presents a promising route in carbon-neutral chemical manufacture. This work systematically investigated the variable interplay between Reverse Water-Gas Shift (RWGS) and Fischer-Tropsch Synthesis (FTS) during CO₂ hydrogenation using model Na-Fe₅C₂ catalysts, combining dynamic/steady-state CO/CO₂ hydrogenation performance, intrinsic kinetics and multiple characterization results. Na-Fe₅C₂ proves to be surface-enriched with FeO_x sites over which RWGS readily proceeds. Meanwhile, CO₂ conversion under integral reaction conditions is limited by the subsequent FTS step due to a lack of available FeC_x sites. The catalyst performance is steered by the properties and relative quantities of the two different active sites. Na addition promotes the refresh of FeO_x sites and β-elimination of alkyl intermediates over FeC_x sites, but at the cost of inhibiting the surface fraction of FeC_x sites and thus the single-pass CO₂ conversion. These fundamental understandings will enlighten further development of CO₂ hydrogenation catalysts with improved hydrocarbon yields.

CO ₂直接加氢生成直链α-烯烃是碳中性化学制造中一条有前景的路线。本工作系统地研究了使用模型 Na-Fe ₅ C ₂催化剂结合动态/稳态 CO/CO ₂加氢性能的 CO ₂加氢过程中反向水煤气变换 (RWGS) 和费托合成 (FTS) 之间的可变相互作用，内在动力学和多重表征结果。Na-Fe ₅ C ₂证明表面富集了 RWGS 容易进行的 FeO _x位点。同时，CO _{2由于缺乏可用的 FeC x}位点，整体反应条件下的转化率受到后续 FTS 步骤的限制。催化剂性能受两个不同活性位点的性质和相对数量的控制。Na添加促进了FeO _{x位点的更新和烷基中间体在FeC x}位点上的β-消除，但以抑制FeC _x位点的表面分数和因此单程CO ₂转化为代价。这些基本认识将启发进一步开发具有改进烃产率的CO ₂加氢催化剂。