Solid materials can exhibit very different surface catalytic properties depending on the exposed surface. Different from the previous finding by Bao et al. (Angew. Chem. Int. Ed. 50 (2011) 12294–12298) that Cu₂O octahedra are more active than Cu₂O cubes in CO oxidation, we found that Cu₂O cubes exposing {100} surface showed significantly higher activity than Cu₂O octahedra exposing {111} surface in the reaction. The Cu₂O(100) surface was found to be oxidized during CO oxidation, leading to the formation of a CuO surface layer. On the other hand, Cu₂O(111) strongly resisted such surface oxidation under CO oxidation conditions. Density functional theory calculations demonstrate that CO oxidation follows a Mars-Van Krevelen mechanism on Cu₂O(111) with a high activation barrier of 1.36 eV. In contrast, the overall activation barrier is only 0.58 eV for CuO(111). These differences explain well the higher activity of oxidized Cu₂O cubes.

固体材料可根据暴露的表面表现出非常不同的表面催化性能。与Bao等人先前的发现不同。（Angew。Chem。Int。Ed。50（2011）12294–12298），在CO氧化中，Cu ₂ O八面体比Cu ₂ O立方体更具活性，我们发现暴露于{100}表面的Cu ₂ O立方体表现出明显更高的活性。比Cu ₂ O八面体在反应中暴露{111}表面。发现Cu ₂ O（100）表面在CO氧化过程中被氧化，导致形成了CuO表面层。另一方面，Cu ₂O（111）在CO氧化条件下强烈抵抗这种表面氧化。密度泛函理论计算表明，CO氧化如下对Cu一个火星范雷维伦机构₂ O（111）与1.36电子伏特的高激活的屏障。相反，CuO（111）的总激活势垒仅为0.58 eV。这些差异很好地解释了氧化的Cu ₂ O立方体的更高活性。