二硫化钒的物相调控及其水分解析氢反应的催化机理研究

Excellent catalysts for hydrogen evolution reaction (HER) are required for the development of hydrogen economy. Metallic 1T-VS2 (octahedral coordination) is a promising two-dimensional layered material, which exhibits excellent HER property. A charge density wave (CDW) phase transition exists in 1T-VS2 near room temperature. The CDW transition leads to lattice distortion, along with the modulation of charge distribution. However, the influence of CDW transition on the HER performance of VS2 has not been explored so far. The CDW transition will bring new opportunities and challenges for elucidating catalytic mechanism of VS2 and optimizing HER activities. The current project focuses on the phase research of VS2 material. The influence of crystal lattice on catalytic property will be explored under various thermodynamic conditions. The main contents are described as follows: 1) Combining experiments with theoretical simulation, we intend to study the lattice reconfiguration and charge redistribution of 1T-VS2 across the CDW phase transition, in order to unveil the processing-structure-property relationship. Thus, the most active phase of VS2 will be clarified. 2) As the electron-phonon coupling and the distribution of electronic states around Fermi surface of two-dimensional material can be adjusted by metal substrate. We attempt to figure out the regulation effect of metal substrate on CDW transition and HER performance. 3) We will investigate the influence of CDW transition on solar energy utilization and stability. So that the application of VS2 in photoelectrochemical devices could be promoted. This project will elucidate the relationship among crystal lattice, electronic structure and catalytic efficiency of VS2, which provides a novel strategy to tune HER ability and deepens knowledge of two-dimensional materials. Thus, this research project has considerable value of practical application for promoting hydrogen energy development.

发展氢经济需要高性能析氢催化剂，1T(八面体结构)-VS2活性高，是极具潜力的金属性二维材料。室温附近1T-VS2存在电荷密度波(CDW)相变，引起晶格畸变，调制电荷分布，目前尚未有研究关注CDW对VS2活性影响。相变对认识VS2催化机理和优化析氢活性带来新的机遇和挑战。本项目聚焦VS2物相研究，阐明不同热力学环境下晶格结构对催化性能影响，包括：1)结合实验和理论，分析CDW相变前后1T-VS2晶格重构和电荷重分配，揭示合成-结构-性能之间关系，探寻VS2活性最强的物相。2)以改变电声耦合强度和费米面附近电子态分布为出发点，厘清金属衬底对CDW相变和催化性能的调控作用。3)研究VS2在光电化学系统中应用，探索CDW相变对太阳能利用率和稳定性影响。本项目构筑VS2晶格结构、电子结构和催化性能的关系模型，提供了一种调控析氢性能的新途径，加深了对二维材料的认知，对推动氢能源发展有着实际应用价值。

本项目设计和合成出了具有高性能的复合催化材料，并对其光电及催化性能进行研究。虽然具体研究内容与实际执行有一定出入，但项目的科学目标已经达到，取得了一系列的研究进展，完成了既定的目标。主要研究成果可简单概括为：(1) 通过界面调控，设计了Se-MoS2/Co0.2Ni0.8Se2复合结构催化剂，暴露出大量活性位点，优化了导电性，分别在碱性、中性和酸性条件下，实现了高效析氢反应。为寻找高活性、低成本、优异稳定性的催化材料和推动氢能源产业落地应用提供科学基础。(2) 通过时间分别的荧光光谱技术手段，分析了CsPbClxBr3-x量子点材料的PL增宽是由于共振和非共振激子辐射重组过程而产生的内在效应。(3) 系统研究了Co2+、Ni2+、Cu2+等离子同氧化石墨(GO)发生作用，凝结的能力。三年来，在项目资助下共发表9篇SCI论文，包括Chin. J. Chem.、Molecules、Desalin. Water Treat.、Appl. Phys. Lett.、Chem. Commun.、Ceram. Int.、Fuel、J. Porous Mater.、RSC Adv.等。积极参加国内外学术会议，并做口头/张贴报告2次。在本项目资助下，指导硕士研究生5人次。