高性能石墨烯垂直有序阵列负载的多元铁族金属磷化物可控制备及其电催化析氢研究

Generally, precious platinum group metals are considered as the most active hydrogen evolution reaction (HER) electrocatalysts. However, their high cost and scarcity hinder large-scale deployment of water electrolysis. The objective of this project is to establish the controllable synthesis of vertically aligned graphene nanosheet arrays with a large specific surface area and high porosity. This will be achieved using uni-directional ice-mould freeze casting; furthermore, the effects of freeze casting conditions on the morphology and structure of the vertically aligned graphene nanosheet arrays will be evaluated. Novel and low-cost non-noble metal composites will be obtained, as electrocatalysts for HER, which display a stable and high catalytic performance that is comparable to that of noble metal catalysts. These composites will be synthesized using electroless plating of multi-metallic iron-group metal phosphides such as Fe1-nNinP on vertically aligned graphene nanosheet arrays. The as-prepared samples will be characterized using various analytical methods and technologies to investigate their surface physical chemistry properties. To establish the controllable synthesis of such vertically aligned graphene nanosheet arrays with plated multi-metallic iron-group metal phosphides as high-performance composite catalysts, the effects of the array structure and electroless plating conditions on the sizes, dispersions, composition, and structure of multi-metallic iron-group metal phosphides will be investigated. Moreover, the relation between catalytic performance and the morphology, components, and structure of the composite catalysts for electrocatalytic HER will be explored by electrochemical measurements at all pH values. The catalysis mechanism of the composite catalysts for HER will be explained in detail using a density functional theory calculation. This project will shed new light on the design of novel, high-performance, yet low-cost non-noble metal electrocatalysts for HER. This will provide theoretical and technical support for low-cost water electrolysis and promote the development of the water electrolysis technique.

铂族贵金属是性能最好的电催化析氢（HER）催化剂。但由于存在价格昂贵及储量有限问题一定程度上制约了电解水制氢技术的大规模应用。本项目拟采用单向冰模板冷冻铸造法，研究冷冻铸造工艺条件对石墨烯垂直有序阵列形貌、结构的影响，建立大比表面、多孔隙率的石墨烯垂直有序阵列载体的可控制备方法；采用化学沉积法，在载体上分别制备Fe1-nNinP等多元铁族金属磷化物，以多种测试手段对其表征，研究化学沉积工艺条件等对多元铁族金属磷化物粒径、分散、成分及结构的影响，建立石墨烯垂直有序阵列负载的多元铁族金属磷化物可控制备方法，以制得成本低、稳定性好、可媲美贵金属的高催化活性HER催化剂；采用电化学测试手段，研究催化剂形貌组成结构在全pH范围内对HER性能的影响，揭示其构效关系，并运用密度泛函理论，探明其催化活性增强机制。该研究将为非贵金属HER催化剂的研制提供参考，为实现低成本电解水制氢技术的规模化应用提供支持。

贵金属铂/碳和二氧化铱/铷是分别用于电解水阴极和阳极的高效电催化剂，但储量匮乏和高成本限制了它们在电解水制氢领域的大规模应用。本项目探索实现铁族金属磷化物材料形貌、组成、结构的可控，进一步增加其导电性、比表面积、活性位点数量和传质效率，主要研究包括建立了杂原子掺杂石墨烯垂直有序阵列载体的可控制备方法；建立了杂原子掺杂石墨烯垂直有序阵列负载的多元铁族金属磷化物可控制备方法；探明了全水解催化剂催化活性增强机制。取得的主要成果如下：.1.采用并研究了冷冻铸造和热处理工艺条件对石墨烯垂直有序阵列形貌、结构、掺杂的影响，提出了多种不同杂原子掺杂的石墨烯垂直有序阵列的可控制备方法。与目前文献报道的石墨烯垂直有序阵列制备方法相比，该法制备的石墨烯垂直有序阵列具有大比表面积、多孔隙率、高度有序排列和优异机械性能等特点。其所以如此，主要是由于该法研究了多种工艺条件对石墨烯垂直有序阵列的影响并建立了相应的调控策略。.2.采用化学沉积法在载体上分别制备了一系列具有不同金属阳离子比例的多元铁族金属磷化物，以多种测试手段对其表征，研究化学沉积工艺条件等对铁族金属化合物粒径、分散、成分及结构的影响，提出了基于杂原子掺杂石墨烯垂直有序阵列负载的多元铁族金属磷化物催化剂的可控制备方法。该法制备的催化剂具有成本低、稳定性好及催化活性高等优点。其之所以具有高催化活性，主要是由于该催化剂可以同时实现增强催化剂导电性、增加活性位点数量、提升本征活性和促进催化传质。.3.采用电化学测试手段，研究催化剂形貌、组成、结构在全pH范围内对全水解性能的影响，揭示了催化剂结构-性能之间的构效关系，并运用密度泛函理论，探明了其催化活性增强机制。.以上研究成果可为全pH范围内高性能非贵金属全水解催化剂的开发奠定基础，为实现低成本电解水制氢技术的规模化应用提供支持，具有重要意义。