Catalytic oxidative dehydrogenation of lower alkanes with CO₂ is an attractive alternative for commercialized dehydrogenation processes not only due to its higher thermodynamic limit but also because it could help reduce anthropogenic CO₂. Here, we studied the catalytic behavior of a Ru-modified conventional SiO₂-supported chromium oxide catalyst and obtained insights into the structure–property relationship for oxidative dehydrogenation of propane (ODP) with CO₂. The catalyst exhibits a volcano-shape propylene production rate trend as Ru loading increases up to 3 wt%. The optimal catalyst with 1 wt% Ru showed a two-fold enhancement in the propylene production rate compared with the unmodified chromium oxide catalyst. We show that a small amount of Ru could help activate CO₂ and remove adsorbed H₂ on the catalyst surface to shift the equilibrium of the direct dehydrogenation reaction, resulting in an increase in its activity without breaking the C–C bonds. Higher loadings of Ru lead to a decrease in activity and selectivity due to the large amount of adsorbed CO₂ that blocks propane adsorption, as well as the high activity of Ru for the reforming reaction of propylene and CO₂. This work demonstrates a new modification of the conventional chromium catalyst for the ODP reaction and its effects on catalytic performance.

中文翻译：

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Ru促进的CO2活化，用于氧化铬催化剂上丙烷的氧化脱氢

用CO ₂催化低级烷烃的氧化脱氢是商业化脱氢方法的一种有吸引力的替代方法，这不仅是因为其较高的热力学极限，而且还因为它可以帮助减少人为的CO ₂。在这里，我们研究了Ru改性的传统SiO ₂负载的氧化铬催化剂的催化行为，并获得了丙烷与CO ₂氧化脱氢（ODP）的结构-性质关系的见解。。随着Ru负载量增加至3wt％，该催化剂表现出火山状丙烯生产速率趋势。与未改性的氧化铬催化剂相比，具有1 wt％Ru的最佳催化剂的丙烯生产率提高了两倍。我们表明，少量的Ru可以帮助活化CO ₂并去除催化剂表面吸附的H ₂，从而改变直接脱氢反应的平衡，从而在不破坏C–C键的情况下提高其活性。由于大量吸附的CO ₂阻碍了丙烷的吸附，并且Ru对丙烯和CO ₂的重整反应具有较高的活性，因此较高的Ru负载量导致活性和选择性降低。。这项工作证明了用于ODP反应的常规铬催化剂的新改进及其对催化性能的影响。