The conversion of carboxylic acid through ketonization process reduces O-atoms and increases CC bonds, which can provide attractive routes for upgrading biomass feedstocks into biofuels. The key factors influencing the surface ketonization activity over CeO₂-based oxides catalysts remain matters of active discourse. Here, a series of Ce_1-xFe_xO_2-δ catalysts were investigated for vapor-phase ketonization of acetic and propionic acid. The catalysts were characterized in detail using various physico-chemical techniques both before and after reaction to gain understanding of the ketonization process. The turnover frequency (TOF) based on the basic sites changed with the Fe content. The Ce_0.8Fe_0.2O_2-δ sample showed the prominent ketonization activity with the highest TOF value. On one hand, for samples with a lower Fe addition (x < 0.3), the formed CeO₂-like solid solution with numerous Ce-O-Fe species showed a dramatic increase in surface oxygen vacancies. These oxygen vacancies were beneficial to catalytic performance. Moreover, the superior redox properties with weaken MO bonds of Ce-O-Fe species thereby promote the ketonization activity. On the other hand, the higher Fe addition (x > 0.3) caused the damage of the Ce-O-Fe structure, thus reducing ketonization activity. Notably, the investigation of the reaction temperature regime of Ce_0.8Fe_0.2O_2-δ sample directly proved the existence of surface redox cycle during the ketonization process.

通过酮化过程进行的羧酸转化减少了O原子并增加了C C键，这可以为将生物质原料转化为生物燃料提供有吸引力的途径。影响基于CeO ₂的氧化物催化剂的表面酮化活性的关键因素仍然是活跃的话题。在此，研究了一系列Ce _1-x Fe _x O2 _-δ催化剂，用于乙酸和丙酸的气相酮化。在反应之前和之后，使用各种物理化学技术对催化剂进行了详细表征，以了解酮化过程。基于基本位点的周转频率（TOF）随Fe含量的变化而变化。铈_0.8 Fe_0.2 O2 _-δ样品的酮化活性显着，TOF值最高。一方面，对于具有较低的Fe添加量（x <0.3）的样品，形成的具有大量Ce-O-Fe物种的类似CeO ₂的固溶体显示出表面氧空位的急剧增加。这些氧空位有利于催化性能。此外，具有减弱Ce-O-Fe物种的M O键的优异的氧化还原特性，从而促进了酮化活性。另一方面，较高的Fe添加量（x＞ 0.3）引起Ce-O-Fe结构的破坏，从而降低了酮化活性。值得注意的是，Ce _0.8 Fe _0.2 O2 _-δ的反应温度范围的研究 样品直接证明了酮化过程中存在表面氧化还原循环。