It is essential to convert SiCl₄ into SiHCl₃ over effective catalysts so as to construct a close-cycle sustainable polysilicon production process. However, the dissociation mechanism of SiCl₄ is elusive yet. Here we adopted density functional theory (DFT) calculation to study the dissociation pathway of SiCl₄, taking into account the effect of possible Cu-Si bond as well as the existing Cl defects in CuCl₂ (1 0 0) surface. The first time we disclose that Cu-Si bond and Cl defect can synergistically catalyze the dissociation of SiCl₄ into SiHCl₃, with the activity superior to either individual Cu-Si bond or Cl defect. The calculation results reflect that on the Si/CuCl₂(1 0 0)-Ⅰ surface, SiCl₄ dissociation is inhibited, due to the lack of Cu-Si bond and low coordination Cu active sites; while the Si/CuCl₂(1 0 0)-Ⅱ surface shows better catalytic activity towards SiHCl₃ formation, comparing with different Cl-defect CuCl₂(1 0 0) surfaces. Microkinetic modeling indicates that the formation rate of SiHCl₃ depends on the intermediate SiCl₃, and the most favorable pathway to generate SiHCl₃ is through SiCl₄ → SiCl₃ + Cl(+H) → SiHCl₃. This work can provide useful guidance on the rational design and synthesis of Cu-based catalysts for the dissociation of SiCl₄ into SiHCl₃ in the polysilicon production.

必须在有效的催化剂上将SiCl ₄转化为SiCl ₃，以构建一个闭环可持续的多晶硅生产工艺。然而，SiCl ₄的离解机理尚不清楚。在这里，我们考虑到可能的Cu-Si键以及CuCl ₂（1 0 0）表面现有的Cl缺陷的影响，采用密度泛函理论（DFT）计算来研究SiCl ₄的解离途径。我们首次公开Cu-Si键和Cl缺陷可以协同催化SiCl ₄分解为SiHCl ₃，其活性优于单独的Cu-Si键或Cl缺陷。计算结果表明，在Si / CuCl ₂（1 0 0）-Ⅰ表面，由于缺乏Cu-Si键和低配位的Cu活性位，抑制了SiCl _4的离解。与不同的Cl-缺陷CuCl ₂（1 0 0）表面相比，Si / CuCl ₂（1 0 0）-Ⅱ表面对SiHCl _3的形成具有更好的催化活性。微观动力学模型表明，SiHCl ₃的形成速率取决于中间体SiCl ₃，产生SiHCl ₃的最有利途径是通过SiCl ₄  →SiCl _3。 + Cl（+ H）→SiHCl ₃。这项工作可为合理设计和合成用于多晶硅生产中的SiCl ₄分解为SiHCl ₃的铜基催化剂提供有用的指导。