Indium–palladium intermetallic catalysts have shown great potential for CO₂ hydrogenation to methanol. A deep understanding of the synergistic relationship between various components is key to developing efficient indium–palladium intermetallic catalysts. Here, we rationally designed a series of catalysts with various In–Pd ratios and found that InPd(2:1)/m-ZrO₂ demonstrated the highest reactivity (5.1 mmol/g_cat/h), maintaining this performance even after 70 h of stability testing at 270 °C and 4 MPa. This impressive performance is attributed to the formation of a stable indium–palladium intermetallic compound with the chemical formula In₃Pd₂ which is close to the In₂O₃ phase during the reduction process. In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and density functional theory (DFT) calculations were further conducted to confirm that the formate path is more favorable for indium–palladium intermetallic catalysts. Adsorption energy calculations of reactants determine the roles of In₃Pd₂ and In₂O₃: In₂O₃ tends to adsorb and activate CO₂, while In₃Pd₂ has an advantage for the dissociation of H₂, which could compensate for the insufficient ability of In₂O₃, thereby promoting the hydrogenation of reaction intermediates. These findings highlight the crucial role of indium–palladium intermetallic compounds in selective CO₂ hydrogenation to methanol.

中文翻译：

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用于选择性 CO2 加氢制甲醇的铟-钯金属间化合物催化剂的合理设计


铟-钯金属间化合物催化剂已显示出 CO₂ 加氢制甲醇的巨大潜力。深入了解各种组分之间的协同关系是开发高效铟-钯金属间化合物催化剂的关键。在这里，我们合理设计了一系列具有不同 In-Pd 比的催化剂，发现 InPd（2：1）/m-ZrO₂ 表现出最高的反应性 （5.1 mmol/g_cat/h），即使在 270 °C 和 4 MPa 下进行 70 小时的稳定性测试后仍保持这一性能。这种令人印象深刻的性能归因于形成稳定的铟-钯金属间化合物，其化学式为 In₃Pd₂，在还原过程中接近 In₂O₃ 相。进一步进行了原位漫反射红外傅里叶变换光谱 （DRIFTS） 和密度泛函理论 （DFT） 计算，以确认甲酸盐路径更有利于铟-钯金属间化合物催化剂。反应物的吸附能计算决定了 In₃Pd₂ 和 In₂O₃ 的作用：In₂O₃ 倾向于吸附和激活 CO₂，而 In₃Pd₂ 对 H₂ 的解离具有优势，可以补偿 In₂O₃ 能力不足，从而促进反应中间体的氢化。这些发现强调了铟-钯金属间化合物在选择性 CO₂ 加氢制甲醇中的关键作用。