碳化钼三维纳米结构的可控构筑、表面结构调控及其析氢性能研究

Molybdenum carbide (Mo2C) is a promising candidate material for hydrogen evolution reaction (HER). As a low-cost and environment-friendly electrocatalysts composed of earth-abundant elements, Mo2C has demonstrated outstanding hydrogen absorption and desorption characteristics with excellent catalytic activity that are analogous to the platinum-group metals. However, Base on the present synthesis methods，it is difficult to construct three-dimensional (3D) nanostructure arrays in situ to remove the surface carbon and control the surface structure. Therefore, this project proposes to improve the catalytic activity of Mo2C by developing a strategy to build 3D Mo2C nanostructure arrays with specific surface structure using a new type of carbonation method from inside to outside combined with template method. The Mo2C-based 3D nanostructure arrays directly used as electrode not only increase the number of exposed active sites, but also accelerate charge and mass transfer in catalytic process. Meanwhile, this strategy provides an effective way to acquire Mo2C 3D nanostructure arrays with Mo-rich surface by finely tuning the penetration rate of carbon source from the body to the surface of Mo layer. Moreover, we will expand systematic study on the orientation regulation of Mo2C surface structures, and then recover the correlation between the exposed surface and catalytic performance of Mo2C nanostructure. Based on the results, it is expected to obtain Mo2C nanostructure catalyst with high catalytic activity and stability through the implementation of this project.

碳化钼具有类似于铂族贵金属的表面性质、氢吸脱附特性；同时原材料储量丰富，价格低廉且环境友好，因而在电催化析氢方面的应用潜力巨大。针对传统碳化钼合成方法中制约其析氢性能的关键问题（难以原位构建三维纳米结构电极、不可避免的表层积碳、难以调控其表面结构），本项目拟开发一种由内而外的新型碳化方式，结合模板法制备表面结构可调的三维碳化钼纳米结构阵列电极，从而增加催化剂有效活性位点数量，促进催化过程中电子及质子的快速传输。这种由内而外的新型碳化工艺的优势在于可有效控制碳化过程中碳源由体相向表层的渗透速率，获得表面富钼的碳化钼纳米结构，进而克服表面积碳对其催化活性的不利影响。同时，系统研究碳化钼表面取向调控，揭示碳化钼表面取向与催化性能之间的构效关系。最终通过三维纳米结构阵列的构筑、表面积碳与表面取向的调控，获得高活性及高稳定性的碳化钼电化学析氢电极。

本项目围绕三维纳米结构的可控构筑、表面结构调控及其电化学性能等研究内容展开了相关研究。开发了高效绿色的制备方法，设计构筑了特定的三维纳米结构；联合利用多种实验手段系统表征了纳米材料的形貌、结构、组分等结构信息，分析了其形成过程及机理，实现了对纳米材料结构的精准调控；详细考察了纳米结构的电化学性能，揭示了材料结构与性能之间的构效关系。本项目研究成果为构筑新型具有优异电化学性能的纳米结构提供了新思路。