以多面体氮化物为核的低铂核壳催化剂的制备及其构效关系研究

The development of low cost, high activity and high stability of the fuel cell cathodic oxygen reduction reaction catalyst is the key to the commercialization of fuel cells. In this project, transition metal nitrides with polyhedral structures (nanosheets, tetrahedrons, cube or octahedron) will be used as the core to design and synthesize low platinum core-shell catalysts with tunable compositions and structures. The exposed crystal face of the platinum shell can be controlled by tuning the morphology of the polyhedron nitride core; meanwhile the stress effect and the electronic effect of the platinum shell can be further regulated by adjusting the composition of the nitride core or depositing the alloyed platinum layers. The key factors for the deposition of the platinum shell will be investigated in detail in order to obtain the rules and key technologies for the preparation of such core-shell structured electrocatalysts, thus revealing the growth mechanism of the platinum shell. The interaction between the structure, compositions and ORR activity of the catalyst will be carefully studied in order to reveal the structure-activity relationship, simultaneously with the assistance of the theoretical calculation that the mechanism of the catalytic performance improvement of the prepared materials can be demonstrated based on the comprehensive analysis. This project has a good theoretical and practical significance for the development of catalyst design concept with high efficiency and low platinum as well as its application in low temperature fuel cells.

研发低成本、高活性和高稳定性的氧还原电催化剂是实现燃料电池商业化的关键。本项目拟采用多面体氮化物纳米结构材料（纳米片、四面体、立方体或八面体等）为催化剂内核，通过沉积超薄铂壳层，合理设计和制备具有结构与组成可控的低铂核壳催化剂。通过调控多面体氮化物内核的形貌结构来控制铂壳层的暴露晶面；通过调整氮化物内核的组分或沉积铂基合金层，来进一步调控铂壳层的应力效应和电子效应。深入研究铂壳层沉积的关键影响因素，掌握该类核壳结构电催化剂制备的规律和关键技术，揭示铂壳层生长机理。同时，研究催化剂形貌结构、组分和氧还原性能和稳定性之间的相互作用，揭示所制备催化剂的构-效关系；结合理论计算分析进而阐明其催化性能改善机制。本项目对于发展高效、低铂核壳结构催化剂的设计理念及其在低温燃料电池中的实际应用，具有良好的理论和实践意义。

研发低成本和长寿命的氧还原电催化剂是实现燃料电池商业化的关键。本项目主要通过制备高性能氮化物基催化剂、利用氮化物和过渡金属合金来调控Pt壳层氧还原催化活性、和改变Pt合金结构和组分等方式来调控Pt基催化剂的应力效应和电子效应，从而制备低铂载量和高性能的氧还原催化剂。系统的研究了催化剂形貌结构、组分和氧还原性能和稳定性之间的相互作用，揭示了所制备催化剂的构-效关系；采用原位表征手段和理论计算分析相结合的方式，进一步阐明了催化性能改善机制。此外，对于优化的催化剂的燃料电池性能也进行了初步探索。在本项目的支持下，共发表SCI论文20余篇，包括Science正刊一篇，一篇Joule邀稿综述；申请国家发明专利4项，培养硕士和博士研究生8人，较好的完成了项目预期目标。该项目的研究成果对于发展高效和高稳定性氧还原催化剂的设计理念及其在低温燃料电池中的实际应用，具有良好的理论和实践意义。