hBN/SiC异质结构上铜团簇的核数调控分子吸附
Nuclearity of Copper Clusters on hBN/SiC Heterostructure Modulates Molecular Adsorption
浏览论文内容
中文总结 AI 辅助
本研究通过DFT结合MLMD模拟，揭示hBN/SiC异质结构硼空位处Cu团簇的核数调控其稳定性、电子结构及气体吸附活性，为2D异质结构的金属功能化提供设计准则。
中文摘要 AI 辅助
缺陷工程可通过为金属原子和团簇创建锚定位点，将惰性二维（2D）材料转化为具有化学活性和电子可调性的平台。然而，对受限在这些缺陷位点的金属物种的形成、热力学与动力学稳定性、电子结构及化学反应活性进行精准调控仍是一项挑战。本研究中，我们采用密度泛函理论（DFT）计算结合机器学习分子动力学（MLMD）模拟，阐明锚定在hBN/SiC异质结构硼空位（VB）处的铜（Cu）团簇的稳定性、电子结构及反应活性。通过系统改变铜与空位的比例，发现VB位点处存在从孤立Cu原子到多原子Cu团簇的转变，团簇生长会重塑稳定性、电子结构及表面反应活性。研究结果表明，单个VB缺陷可被3个Cu原子钝化，这3个Cu原子通过Cu-N配位补偿局部电荷缺陷并稳定该缺陷；捕获更多Cu原子会引入局域隙间态，可能影响Cu修饰缺陷位点的反应活性。我们探究了Cu修饰表面对相关化学气体CO、H₂、O₂、N₂、H₂S及CO₂的响应，揭示其对表面反应活性和稳定性的影响。计算显示，VB位点处Cu团簇的反应活性具有显著的团簇尺寸依赖性，其中CO会形成强Cu-C键，O₂则表现出增强的吸附和分子活化。总体而言，本研究确定了缺陷工程化的hBN/SiC是一种可用于稳定Cu团簇并调控气-表面反应活性的多功能2D平台；通过关联VB位点处Cu核数与电子结构、分子活化及环境稳定性，研究结果为2D异质结构中核数依赖型金属功能化提供了设计准则。
英文摘要
Defect engineering can transform inert two-dimensional (2D) materials into chemically active and electronically tunable platforms by creating anchoring sites for metal atoms and clusters. Nevertheless, precise control over the formation, thermodynamic and kinetic stability, electronic structure, and chemical reactivity of metal species confined at these defect sites remains a challenge. Here, we use density functional theory (DFT) calculations assisted by machine-learning molecular dynamics (MLMD) simulations to elucidate the stability, electronic structure, and reactivity of Cu clusters anchored at boron vacancies (VB) in hBN/SiC heterostructures. Systematic variation of the Cu-to-vacancy ratio reveals a transition from isolated Cu atoms to multiatom Cu clusters at VB sites, with cluster growth reshaping the stability, electronic structure, and surface reactivity. Our results show that a single VB defect can be passivated by three Cu atoms, which compensate the local charge deficiency and stabilize the defect through Cu-N coordination. Capturing further Cu introduces localized midgap states that could influence the reactivity of the Cu-decorated defect sites. We probe the response of the Cu-decorated surface to chemically relevant gases CO, H2, O2, N2, H2S, and CO2, revealing implications for surface reactivity and stability. The calculations show pronounced cluster-size-dependent reactivity of Cu clusters at VB sites, with CO forming strong Cu-C bonds and O2 undergoing enhanced adsorption and molecular activation. Overall, this work identifies defect-engineered hBN/SiC as a versatile 2D platform for stabilizing Cu clusters and tuning gas-surface reactivity. By correlating Cu nuclearity at VB sites with electronic structure, molecular activation, and environmental robustness, our findings provide design guidelines for nuclearity-dependent metal functionalization of 2D heterostructures.
