Pt基金属纳米晶电化学重构调控及其电催化性能研究

Pt-based metal nanocrystals catalyst with controllable composition, morphology and structure could improve the activity, stability and efficiency, which has always been a major scientific problem and key technical problem in related fields. A two-step preparing method in this project was used to prepare clean Pt-based metal nanocrystals, which involves in the model catalysts preparation and the reconstruction of model catalysts using electrochemical method. A series of transition metals doped Pt-based metal nanocrystals with controllable chemical composition, atomic arrangement, morphology and structure were prepared by this method. The effects of electrochemical parameter and electrolyte solution on the reconstruction of model catalysts were investigated systemically. Combined to theoretical simulation calculation, the reconstruction mechanism of model catalysts by electrochemical method would be further clarified. The electrocatalytic activity and stability of the obtained Pt-based metal nanocrystals were measured. The relationships between composition, atomic arrangement, morphologies and structure and electrocatalytic property were uncovered, and the corresponding relation model was established. The above research work has important scientific and practical application significance for developing the new high-efficient electrocatalysts.

制备成分、形态和结构等可控的Pt基金属催化剂来提高其催化活性、稳定性和利用效率一直是相关领域的重大科学问题和关键技术问题。本项目提出采用两步法进行Pt基金属纳米晶催化剂的可控制备，即在模型催化剂的基础上，利用电化学调控方法对模型催化剂进行电化学重构调控，获得一系列化学成分、原子排列和形貌结构可控的过渡金属掺杂Pt基金属催化剂。系统研究电化学参数和支持电解质等对模型催化剂重构过程的影响规律和作用机制，并结合理论模拟计算，对模型催化剂电化学重构机理给出深入的理论解释。通过系统考察制备的Pt基金属纳米晶的电催化性能，阐明Pt基金属纳米晶化学成分、原子排列结构和形貌结构与催化性能之间的内在联系和规律，建立材料特性与电催化行为和催化机制之间的内在关系模型，这对于高效催化剂的设计和优化以及加速新型高性能电催化剂的研发进展具有重要的科学意义和实际应用价值。

目前Pt族催化剂作为燃料电池的技术关键及成本关键，是质子交换膜燃料电池和直接醇类等燃料电池中尚难以被替代的催化剂。然而，由于价格昂贵、含量稀少而限制了其大规模的商业化应用。因此，发展低使用量、高活性和高稳定性的Pt族对金属电催化剂始终是电催化领域研究的热点和关键问题。本项目围绕Pt和Pd及其合金催化剂的设计合成及催化性能开展了系统深入的研究，通过电化学调控方法合成了形貌可控、尺寸均一的Pt和Pd贵金属及其合金催化剂，系统研究了脉冲方波修饰频率、修饰时间、沉积电位和前驱体溶液浓度等合成工艺参数对催化剂尺寸以及表面结构形貌、成分和原子排列结构的影响作用，揭示了其影响规律，阐明了电化学调控合成过程中周期性电位脉冲上下限电位和频率、处理时间等合成工艺参数对产物表面原子的选择性溶解和再沉积影响的作用机理，构建了相关的物理化学模型，揭示了催化材料微观结构形貌、组分和电催化性能之间的内在联系，为高性能金属纳米催化剂设计合成提供了理论依据。围绕以上相关研究结果，在Adv. Funct. Mater.、Angew. Chem. Int. Ed、Catalysts、Int. J. Electrochem. Sci.等国际期刊共发表SCI收录论文5篇(标注有基金资助)，申请发明专利3项，培养2名硕士生。