Hydrogenation of CO₂ to ethanol is an efficient process for the utilization of CO₂ along with the production of value-added chemicals. However, CO₂ hydrogenation to ethanol is a complicated reaction, requiring the catalyst to activate CO₂ efficiently and accurately regulate the C–C coupling to achieve a high ethanol selectivity simultaneously. Herein, we report the synthesis of RhFeO_x catalysts supported on TiO₂ with different crystal phase compositions (anatase, rutile, and P25), which were applied for the selective CO₂ hydrogenation to ethanol. The RhFeO_x/P25 catalyst presented a high dispersion of Rh nanoparticles on the P25 support with abundant Rh⁰–Rh^δ+–O_V–Ti³⁺ (O_V: oxygen vacancy) interfacial sites over the anatase/rutile junction. The optimized RhFeO_x/P25 catalyst exhibited a high ethanol space–time yield of 18.7 mmol g_cat^–1 h^–1 and a high Rh turnover frequency of 544.8 h^–1 with 90.5% ethanol selectivity. An in-depth investigation via various ex situ and in situ characterizations as well as H₂/D₂ exchange and C₂H₄ pulse hydrogenation experiments demonstrated that the Rh⁰–Rh^δ+–O_v–Ti³⁺ interfacial sites played a crucial role in the conversion of CO₂ to ethanol. The surface Rh⁰ sites facilitated the CO₂ activation and hydrogenation, while the Rh⁰–Rh^δ+–O_v–Ti³⁺ interfacial sites boosted the C–C coupling to produce ethanol. The high-performance RhFeO_x/P25 catalyst also provides an attractive route for highly efficient ethanol synthesis via CO₂ hydrogenation.

中文翻译：

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在 RhFeOx/P25 上构建活性 Rh-TiOx 界面位点，实现 CO2 高效加氢制乙醇


将 CO₂ 氢化为乙醇是利用 CO₂ 以及生产增值化学品的有效过程。然而，CO₂ 加氢制乙醇是一个复杂的反应，需要催化剂有效地激活 CO₂ 并准确调节 C-C 偶联，以同时实现高乙醇选择性。在此，我们报道了负载在 TiO₂ 上具有不同晶相组成（锐钛矿、金红石和 P25）的 RhFeO_x 催化剂的合成，这些催化剂应用于选择性 CO₂ 加氢制乙醇。RhFeO_x/P25 催化剂在 P25 载体上呈现 Rh 纳米颗粒的高分散性，在沉沸石/金红石结上具有丰富的 Rh^{0-Rh δ+–}O_V-Ti ³⁺（O_V：氧空位）界面位点。优化的 RhFeO_x/P25 催化剂表现出 18.7 mmol g_cat^–1 h^–1 的高乙醇时空产率和 544.8 h^–1 的高 Rh 周转频率，乙醇选择性为 90.5%。通过各种非原位和原位表征以及 H₂/D₂ 交换和 C₂H₄ 脉冲加氢实验的深入研究表明，Rh⁰–Rh^δ–O_v–Ti³⁺ 界面位点在 CO₂ 转化为乙醇中起着至关重要的作用。表面 Rh⁰ 位点促进了 CO₂ 活化和氢化，而 Rh⁰–Rh^δ+–O_v-Ti ³⁺ 界面位点促进了 C-C 偶联以产生乙醇。 高性能 RhFeO_x/P25 催化剂还为通过 CO₂ 加氢实现高效乙醇合成提供了一种有吸引力的途径。