纳米空间限域还原场中铂基纳米晶高枝化结构形成机理及电催化特性研究

燃料电池作为未来能源储存和转换装置，是公认的能源利用终极形式之一。但是真正利用燃料电池仍面临着一系列重要的关键性科学问题亟待解决。其中，Pt基催化剂的催化效率是最为核心的问题之一。前期工作中，申请人在自主构建的纳米空间限域还原场中，不使用任何功能分子获得了具有洁净表面且高枝化结构特征的铂基纳米晶，跳出了溶液合成法的极限。与市售铂黑相比，其纯铂和双金属铂基催化剂的电催化质量活性提高了17倍和55倍。申请人相信，在前期坚实的研究基础上，展开本项目研究工作，对于探索限域还原场中高枝化结构的形成机理，阐明纳米晶高枝化结构与电催化活性之间构效关系，从而在微纳米层面上理解纳米空间限域还原场特性，揭示运动核-内空间-孔道三相间金属枝化物异相生长的本质和特征，完善d-带理论匹配的多金属限域还原体系，进而构建超高性能燃料电池系统，探索超高效太空宇航发动机等方面，是具有一定学术价值和意义的。

Fuel cells were currently being studied in most energy development fields as future green energy sources. However, for its genuine commercialization, a few remaining barriers still need to be overcome. The most urgent problem is to enhance the mass activity of a Pt electrocatalyst, reducing the production cost of fuel cells significantly. In our previous works, we proposed a functional agent-free nanoconfinement photoreduction method to produce well-dispersed and clean-surface Pt nanodendrites. The method is a choice for preparation of metal nanocrystals with clean surface, which emancipate from limitation of solution-based synthesis for almost 20 years. The results show that the pure Pt nanodendrites and Pt/Pd nanodendrites exhibit a high specific surface area and superior electrocatalytic activity, which are 17 times and 55 times higher than that of commercial Pt black toward methanol oxidation reaction. Despite all the above empirical investigations, we still have very limited understanding of this novel system and have much to discover, such as characteristics of nanoconfinement photoreduction system, the mechanism of moving core/nanovoid/nanochannel and dendrite structure and relationship between dendrite structure and activity, etc. We believe these investigations will pave the way for the further development of fuel cell applications.