TiCx中碳空位与掺杂元素的形成机制及分布特性研究

Due to the common existence of carbon vacancies and doping elements in TiCx, studying the feasibility of utilizing these defects to control properties of TiCx is important for its efficient and stable application. Therefore, in this project, computer simulation and experimental methods are used to study the formation mechanism and distribution characterization of carbon vacancies and doping elements in TiCx, and the influence of these defects on the properties is also discussed. At first, the computer simulation method is used to analyze the formation and distribution of carbon vacancies and doping elements. In this section, the analysis mainly focuses on the surface segregation of the defects and if their distribution is ordered or not. In addition, the migration of carbon vacancies and doping elements in TiCx is also studied. Then, the formation mechanism of carbon vacancies and doping elements in TiCx is studied by experimental method. Based on the results, TiCx particles with different contents of carbon vacancies and different kinds of doping elements are obtained, and the content and distribution of the defects are analyzed by XPS, HTEM .etc. At the same time, the results should be compared with the simulation results. Finally, the morphologies, crystal structure and properties of prepared TiCx are analyzed in order to establish the relationship between the carbon vacancies/doping elements and the properties. According to the above results, the new preparation method is exploited to individually or jointly control the carbon vacancies and doping elements in order to prepare TiCx with high performance and stability.

由于实际制备的TiCx中碳空位及掺杂元素的的普遍存在，探究利用这些缺陷调控TiCx性能的可行性，是其能够高效、稳定利用的重要方面。因此，本项目拟以TiCx中的碳空位及掺杂元素为主要研究对象，运用计算机模拟和试验相结合的手段探索其形成机制及分布特性，同时分析它们对TiCx性能等的影响。首先，利用模拟技术研究碳空位与掺杂元素的形成及分布，重点分析其表面偏析情况、分布的有序度以及其在TiCx中迁移的难易程度；其次，通过试验手段探索碳空位及元素掺杂的形成机制，在此基础上制备具有不同空位含量及掺杂不同元素的TiCx，利用XPS、HTEM等手段分析其实际含量及分布情况，并与模拟结果相互印证；最后，分析不同TiCx的形貌、晶体结构并测定其性能，建立碳空位及掺杂元素与形貌、结构及性能之间的关系。通过上述研究，开发新的TiCx合成工艺，利用碳空位及掺杂元素的单独或联合调控制备高性能、高稳定性的TiCx。

本项目以TiCx中的碳空位及掺杂为主要研究对象，围绕碳空位与掺杂的形成机制及分布特性开展相关研究工作。通过研究明确了非化学计量比TiCx中碳空位的表面偏析倾向和有序化倾向，阐明了碳空位及其有序化对TiCx中层错形成的诱导作用；分析了B在TiCx不同晶面的吸附能力，建立了B吸附与TiCx形貌之间的关系；对比研究了Au在完美TiC和含空位TiCx表面的不同吸附特性，探明了碳空位对Au吸附的影响，为利用碳空位调控开发高效Au/TiC催化体系奠定了基础；研究了H在TiCx中的掺杂和扩散能力，明确了H在含空位TiC层错层中的易扩散性；结合Si等元素掺杂对层错形成的影响，提出了利用碳空位与掺杂联合诱导层错，开发高性能TiC储氢材料的设想；开发了铜熔体中TiC自生反应合成技术并分析了TiC合成机理，为TiC增强铜基复合材料的开发提供了技术支持。