The reaction of captured carbon dioxide with renewable hydrogen towards the eventual indirect production of liquid hydrocarbons via CO₂ reduction to CO (reverse water-gas shift reaction, rWGS) is a promising pathway in the general scheme of worldwide CO₂ valorization. Copper-ceria oxides have been largely employed as rWGS catalysts owing to their unique properties linked to copper-ceria interactions. Here, we report on the fine-tuning of CuO/CeO₂ composites by means of alkali promotion. In particular, this work aims at exploring the effect of cesium doping (0–4 atoms Cs per nm²) on co-precipitated CuO/CeO₂ catalysts under CO₂ hydrogenation conditions. The as-prepared samples were characterized by N₂ physisorption, X-ray diffraction (XRD), H₂-temperature programmed reduction (H₂-TPR), X-ray photoelectron spectroscopy (XPS), CO₂-temperature programmed desorption (CO₂-TPD), Fourier-transform infrared spectroscopy (FTIR) of pyridine adsorption and CO-diffuse reflectance Fourier-transform infrared spectroscopy (CO-DRIFTS). The results demonstrated that a low amount of Cs exerted a beneficial effect on CO selectivity, inhibiting, however, CO₂ conversion. Specifically, a doping of 2 atoms Cs per nm² offers > 96 % CO selectivity and equilibrium CO₂ conversion at temperatures as low as 430 °C, whereas further increase in cesium loading had no additional impact. The present findings can be mainly interpreted on a basis of the alkali effect on the textural and acid/base properties; Cs doping results in a significant reduction of the surface area and thus to a lower population of active sites for CO₂ conversion, whereas it enhances the formation of basic sites and the stabilization of partially reduced Cu⁺ species, favoring CO selectivity.

捕获的二氧化碳与可再生氢的反应，通过将CO ₂还原为CO最终间接产生液态烃（逆水煤气变换反应，rWGS），是在全球范围内进行CO ₂增值的一般方案中的一个有希望的途径。氧化铜-氧化铈由于其与氧化铜-氧化铈相互作用相关的独特性能而被广泛用作rWGS催化剂。在这里，我们报告了通过碱促进对CuO / CeO ₂复合材料的微调。特别是，这项工作旨在探索铯掺杂（0-4个原子Cs / nm ²）对CO ₂下共沉淀CuO / CeO ₂催化剂的影响。氢化条件。制备的样品的特征在于N ₂物理吸附，X射线衍射（XRD），H ₂程序升温还原（H ₂ -TPR ），X射线光电子能谱（XPS），CO ₂程序升温解吸（CO）₂ -TPD），吡啶吸附的傅里叶变换红外光谱法（FTIR）和CO扩散反射率傅里叶变换红外光谱法（CO-DRIFTS）。结果表明，少量的Cs对CO的选择性发挥了有益的作用，但是抑制了CO _2的转化。具体而言，每nm ²掺杂2个原子Cs可提供> 96％的CO选择性和平衡的CO _2。在低至430°C的温度下转化，而铯负载的进一步增加没有其他影响。本发现主要可以根据碱对质地和酸/碱性质的影响来解释。Cs掺杂会导致表面积显着减少，从而减少用于CO ₂转化的活性位点的数量，而它会增强碱性位点的形成和部分还原的Cu ⁺物种的稳定性，有利于CO的选择性。