The conversion of the highly selective CO₂ reduction reaction (CO₂RR) into desired value-added multicarbon compounds, like C₂H₄, is crucial, but it is mainly constrained by the high energy barrier for C–C coupling and the multi-electron transfer process. Herein, M/TiO₂ and M/TiO₂–V_O (M = Cu, Pd, CuPd, and V_O refers to the surface oxygen vacancy) catalysts were designed to study the CO₂RR towards C₂H₄ by using density functional theory (DFT). We found that the surface oxygen vacancy enhances the adsorption ability of studied catalysts. The CO₂ molecule is strongly adsorbed at the metal–surface interfaces of Cu/TiO₂–V_O, Pd/TiO₂–V_O and CuPd/TiO₂–V_O catalysts with adsorption energies of −1.79, −1.75 and −1.71 eV, respectively. Furthermore, the C–C coupling reaction does not occur on the Cu and PdCu cluster sites of the M/TiO₂–V_O catalysts, indicating the inactivity of these sites for C₂ products. However, Pd/TiO₂, CuPd/TiO₂ and M/TiO₂–V_O interfaces favor the C–C coupling reaction and therefore have the potential to reduce CO₂ to C₂ products. Additionally, the Gibbs free energy calculations reveal that the surface oxygen vacancy improves the OCCO hydrogenation to C₂H₄ at the CuPd/TiO₂–V_O interface.

中文翻译：

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表面氧空位对金属（Cu、Pd、CuPd）负载 TiO2 催化剂对 CO2 吸附及其对 C2H4 活化的影响：第一性原理研究


将高选择性 CO₂ 还原反应 （CO₂RR） 转化为所需的增值多碳化合物（如 C₂H₄）至关重要，但它主要受到 C-C 耦合和多电子转移过程的高能垒的限制。本文设计了 M/TiO₂ 和 M/TiO₂–V_O （M = Cu、Pd、CuPd 和 V_O 是指表面氧空位）催化剂，利用密度泛函理论 （DFT） 研究了 CO₂RR 朝向 C₂H₄ 的变化。我们发现表面氧空位增强了所研究催化剂的吸附能力。CO₂ 分子强烈吸附在 Cu/TiO₂–V_O、Pd/TiO₂–V_O 和 CuPd/TiO₂–V_O 催化剂的金属表面界面上，吸附能分别为 -1.79、-1.75 和 -1.71 eV。此外，C-C 偶联反应不会发生在 M/TiO_{2-V O} 催化剂的 Cu 和 PdCu 簇位点上，这表明这些位点对 C₂ 产物无活性。然而，Pd/TiO₂、CuPd/TiO₂ 和 M/TiO₂–V_O 界面有利于 C-C 偶联反应，因此有可能将 CO₂ 还原为 C₂ 产物。 此外，吉布斯自由能计算表明，表面氧空位在 CuPd/TiO₂–V_O 界面处将 OCCO 氢化提高到 C₂H₄。