The higher capacity of CO₂ adsorption on the surface of magnesium oxide (MgO) with low-coordination O²⁻ sites would effectively enhance the catalytic reduction of CO₂. Herein, a series of copper oxide (CuO) and MgO composites with different mass ratios have been prepared by hydrothermal method and used for photothermal synergistic catalytic reduction of CO₂ to ethanol. The catalyst with CuO mass ratio of 1.6% shows the best yield (15.17 μmol·g⁻¹·h⁻¹) under 3 h Xenon lamp illumination. The improved performance is attributable to the loose nano-sheet structure, uniform dispersion of active sites, the increased specific surface area, medium-strength basicity, the high separation efficiency of electrons and holes, and the formation of Mg−O−Cu species. The synthesized CuO and MgO composites with loose nano-sheet structure facilitate the diffusion of reactants CO₂, so an excellent CO₂ adsorption performance can be obtained. Meanwhile, the introduction of CuO in the form of bivalence provides higher specific surface area and porosity, thus obtaining more active sites. More importantly, the Mg−O−Cu species make the donation of electrons from MgO to CO₂ easier, resulting in the breaking of the old Mg-O bond and the formation of C—O bond, thus promoting the adsorption and conversion of CO₂ to ethanol.

^{具有低配位O 2−}位点的氧化镁(MgO)表面对CO ₂的吸附能力较高，可有效增强CO ₂的催化还原作用。本文采用水热法制备了一系列不同质量比的氧化铜(CuO)和MgO复合材料，并将其用于光热协同催化还原CO ₂制乙醇。CuO质量比为1.6%的催化剂在氙灯照射3 h下表现出最佳收率(15.17 μmol·g ^-1 ·h ^{-1 )。}性能的改善归因于疏松的纳米片结构、活性位点分散均匀、比表面积增加、中等强度 碱度、电子和空穴的高分离效率以及 Mg−O−Cu 物种的形成。_{合成的CuO和MgO复合材料具有疏松的纳米片结构，有利于反应物CO 2}的扩散，因此可以获得优异的CO _{2吸附性能。}同时，以二价形式引入CuO提供了更高的比表面积和孔隙率，从而获得更多的活性位点。更 重要的是，Mg−O−Cu物种使MgO更容易向CO ₂提供电子，导致旧的Mg-O键断裂并形成CO键，从而促进CO的吸附和转化₂乙醇。