In heterogeneous catalysis, on one hand, people always want to know about reaction details, such as what the most active phase is, how it is formed, and what is the reaction mechanism. On the other hand, it is still very challenging to probe these reaction details, particularly at high reaction temperatures and pressures. Here, we report the microcrystal plane-controlled catalytic performance on well-defined Cu₂O cube, octahedron, and rhombic-dodecahedron catalysts in the Rochow reaction. It was found that the Cu₂O cube exposing {1 0 0} crystal planes gave the highest dimethyldichlorosilane selectivity and yield, while the Cu₂O rhombic-dodecahedron exposing {1 1 0} crystal planes showed the lowest selectivity and yield. Our experimental observation, as well as density functional theory calculations, demonstrated that the enhanced selectivity and yield stemmed from the stronger dissociative adsorption of methyl chloride on the Cu₂O{1 0 0} plane, which greatly promoted the transformation of Cu₂O into Cu₃Si active phases under the reaction conditions. This work reveals a new strategy for controlling the surface structure of catalysts in order to enhance their catalytic performance.

一方面，在非均相催化中，人们总是想了解反应的详细信息，例如最活跃的相是什么，如何形成的以及反应机理是什么。另一方面，探测这些反应细节仍然是非常具有挑战性的，特别是在高反应温度和压力下。在这里，我们报告在Rochow反应中，对明确定义的Cu ₂ O立方，八面体和菱形十二面体催化剂的微晶面控制催化性能。发现暴露{1 0 0}晶面的Cu ₂ O立方晶具有最高的二甲基二氯硅烷选择性和产率，而Cu ₂菱形十二面体暴露{1 1 0}晶面显示出最低的选择性和产率。我们的实验观察以及密度泛函理论计算表明，选择性的提高和产率的提高归因于氯甲烷在Cu ₂ O {1 0 0}平面上更强的解离吸附，从而极大地促进了Cu ₂ O转化为Cu 2O。反应条件下的Cu ₃ Si活性相。这项工作揭示了控制催化剂表面结构以增强其催化性能的新策略。