The oxidation of ethylene (C₂H₄) to produce value-added chemicals such as ethylene oxide is an important chemical process in industry. We investigated the oxidation of C₂H₄ by O₂ catalyzed by an Ag-atom embedded boron-nitride nanosheet (Ag/h-BN) using density functional theory calculations. The adsorption energies of O₂ and C₂H₄ molecules on Ag/h-BN are -0.85 and -1.21 eV, respectively, demonstrating that C₂H₄ has a stronger tendency to interact with this surface. A trimolecular Langmuir-Hinshelwood mechanism involving the -CH₂CH₂OOCH₂CH₂- intermediate was found as the most efficient pathway for C₂H₄ epoxidation. This intermediate is converted into two ethylene oxide molecules after passing over an activation barrier of 0.44 eV. The competing pathway to produce an acetaldehyde molecule has a very high activation barrier, indicating that C₂H₄ epoxidation can occur selectively over Ag/h-BN. These findings may be useful for modeling and designing high performance and selective single-metal catalysts for ethylene epoxidation.

将乙烯 (C ₂ H ₄ )氧化为生产环氧乙烷等增值化学品是工业中的重要化学过程。我们使用密度泛函理论计算研究了由嵌入 Ag 原子的氮化硼纳米片 (Ag/ h -BN)催化的 O ₂对 C ₂ H ₄的氧化。O ₂和C ₂ H ₄分子在Ag/ h -BN上的吸附能分别为-0.85 和-1.21 eV，表明C ₂ H ₄与该表面相互作用的趋势更强。涉及-CH的三分子Langmuir-Hinshelwood机制₂ CH ₂ OOCH ₂ CH ₂ - 中间体被发现是最有效的C ₂ H ₄环氧化途径。该中间体在通过 0.44 eV 的活化势垒后转化为两个环氧乙烷分子。产生乙醛分子的竞争途径具有非常高的活化屏障，表明C ₂ H ₄环氧化可以选择性地发生在Ag/ h- BN之上。这些发现可能有助于模拟和设计用于乙烯环氧化的高性能和选择性单金属催化剂。