铂基纳米晶/石墨烯杂化材料的可控合成及催化析氢研究

The electrocatalytic hydrogen evolution is a promising way for hydrogen production. It is, therefore, of scientific importance to design efficient electrocatalysts. Although Pt remains most active for hydrogen evolution due to its appropriate adsorption to H, the wide applications have been limited by its scarcity and high cost. Thus it is highly desirable to develop new electrocatalysts with low cost and high activity, which is the key to the cost control of catalysts. Graphene is characterized by a large surface area and a unique structure, the project intends to guide the Pt-based nanocrystals growth by using graphene as the substrate, preparing shape-controlled Pt-based nanocrystals/graphene hybrid materials. The project is to explore the role of graphene in controlling the size, morphology and dispersity of Pt-based nanocrystals, to reveal the growth mechanisms of Pt-based nanocrystals. The project will then systematically investigate the electrochemical behavior of the hybrid materials, and explore the composition, size, morphology, dispersity and Pt-graphene interations for electrocatalytic hydrogen evolution, and primarily elucidate the relationship between the microstructure and their catalytic performances. The research of this project will provide theoretical guidance for the controllable preparation of Pt-based/graphene hybrid materials and the development of efficient electrocatalysts for hydrogen evolution.

电催化析氢是一类具有应用前景的产氢方式，设计合成性能高效的析氢催化剂具有重要的科学意义。研究发现铂对氢的吸脱附能力适中，是当前析氢效率最高的催化剂。但是铂储量有限，价格昂贵，如何提高催化剂活性，降低铂的用量，已成为控制催化剂成本的关键。鉴于石墨烯具有高比表面积和特殊的表面结构等特点，本项目拟采用石墨烯做基底，引导铂基纳米晶的生长，制备形貌可控的铂基纳米晶/石墨烯杂化材料，以期提高铂的利用率。研究石墨烯对铂基纳米晶的尺寸、形貌、分散度等方面的调控作用，揭示铂基纳米晶在石墨烯表面的生长机制；系统考察所得杂化材料在催化析氢反应的电化学行为，深入研究铂基纳米晶的组成、尺寸、形貌、分散度、石墨烯与铂基纳米晶之间的相互作用对析氢性能的影响；初步阐明杂化材料的微观结构与其析氢性能之间的相关性，为制备形貌可控的铂基纳米晶/石墨烯杂化材料和开发具有优异性能的低成本析氢催化剂奠定理论基础。

项目围绕铂基纳米晶展开，探索和制备了多种铂基催化剂用于电催化产氢方面，深入研究并探讨了铂基纳米晶的组成、尺寸及微观结构对电催化产氢性能的影响，为设计开发性能优异的低成本析氢催化剂提供了理论基础。基于电催化析氢反应中载体对铂基催化剂催化性能的影响，成功制备了小尺寸铂铜八面体负载的氮掺杂碳纤维复合纳米材料，研究发现尺寸仅为4.5 nm的铂铜纳米晶可以提供更多的催化活性位点，而N原子的掺入进一步提供了缺陷位点并增强了催化剂的导电性。其次，以含氧酸盐基的金属有机框架材料为前驱体，煅烧制备了碳化钼负载铂铜纳米晶的电催化剂，其中Pt和Cu之间的电子效应以及Mo2C与Pt-Cu之间的协同作用都为催化剂的高活性和高稳定性提供了支撑。另外，采用还原氧化石墨烯(RGO)辅助的水热法制备了MoS2/RGO复合纳米材料，探讨了所得MoS2中1T相与2H相的比例对电催化产氢的活性和稳定性的影响，研究发现RGO与MoS2之间生成的Mo-O键可以有效阻止MoS2从1T相向2H相的转变，该工作为制备高稳定性的1T相MoS2提供了新思路。