二硫化钼(MoS2) 由于具有着突出的光学、电学、催化等性能近来受到了广泛的关注。研究发现缺陷直接影响MoS2特别是单层MoS2各方面的性质，但其影响机理至今仍然不清楚。为了阐明缺陷影响MoS2性质的机理，进而指导对MoS2性能的优化，本项目中我们将系统的研究离子束辐照对MoS2中的缺陷状态及电子结构的影响。我们将以具有可控结构及组成的单层及单晶块体MoS2作为模型材料体系，通过控制离子辐照的离子能量、剂量等参数在材料中引入可控缺陷，并系统研究辐照造成缺陷的种类、数量及分布等性质与局域电子结构的关系。此外，针对能源领域的应用，我们还将研究不同离子辐照条件对MoS2的析氢反应活性的影响，并从辐照引起缺陷状态及电子结构变化的角度，揭示这种影响的机理。我们的研究方法和科学结论可直接扩展至其他过渡金属硫化物，具有重要的基础研究意义和应用价值。

Molybdenum disulfide (MoS2) has attracted great attentions due to their extraordinary optical, electrical, and catalytic properties. Although defects are found to greatly influence the properties of MoS2, the mechanism of such influence is still not clear. In order to understand the impact defects and guide the design of new materials through defect engineering, in this work, we will systematically study how ion beam irradiation impacts the defects states and local electronic structure of MoS2. We will firstly synthesis MoS2 model system with well-defined structure and chemistry. Then we will investigate how ion energy and fluence of ion beam irradiation impact the defect states such as the defect type and density in MoS2, and identify the correlation between the defect states and the local electronic structure. Lastly, for the application of energy conversation, we will investigate the influence of ion beam irradiation on the hydrogen evolution reaction activity of MoS2. Such influence will then be explained through changes in defect states and local electronic structure. The approach we use and the knowledge we obtain in this project are applicable to other transition-metal dichalcogenides and therefore with great importance.