表面非晶化核壳纳米线阵列的可控制备及电解水性能研究

Amorphous nanomaterials have been extensive research due to their unique structure merits of short-range structural ordering and high active site density, which render them promising candidates in electrocatalysts applications. But the low electrical conductivity limits its electrochemical performance. Conductive metal-organic framesworks can not only provide a large specific surface area and porosity, but also have good conductivity, therefore, the combination of conductive metal-organic framesworks and amorphous nanomaterials is one of the effective strategies to solve the conductivity of amorphous nanomaterials and improve their electrocatalytic activity. The aim of this project is to develop an effective chemical method for fabricating the amorphous Co-base sulfides, selenides and Ni-base phosphates by using size-controlled conductive metal-organic framesworks (Co and Ni based conductive metal-organic framesworks) as the templates. In this project, we will focus on the following two surface-controlled chemical conversion strategies: (1) a combined method of anion exchange reaction.and organic component removal, (2) liquid phase phosphating reaction. Furthermore, we will investigate systematically their electrochemical performance toward electrocatalytic water splitting, and study the structure-activity relationship and electrocatalytic mechanism by theoretical calculation and structural simulation. The research result would provide theoretical guidance and experimental basis for the design and synthesis of highly efficient and stable water splitting electrocatalysts.

非晶纳米材料以独特的结构特点、短程结构有序性和高活性位密度等优点受到广泛地研 究，在催化剂领域具有广阔的应用前景。但因差导电性限制其电化学应用。导电金属有机框架 既可提供较大比表面积和孔隙率，又具有良好导电性，因此将导电金属有机框架与非晶 纳米材料复合是解决非晶态纳米材料差导电性、提高电催化活性的有效策略之一。本项目旨在发展一种有效的化学方法在三维导电基底上制备尺寸可控的导电金有机框架（钴基和镍基导电金属有机框），并以此为模板在有机溶剂中通过控制表面有机反应（阴离子交换反应-有机组分移除和液相磷化反应），最终实现表面非晶钴基硫化物、硒化物和镍基磷化物导电金属有机框架核壳纳米线阵列的制备。系统地研究所得催化剂的电解水性能，并结合理论计算和结构模拟解释催化剂的结构、组成和表面晶态与电催化性能之间的构效关系，揭示电催化机理，为设计合成高效、稳定的电解水催化剂提供理论指导和实验依据。

伴随着生产力的飞速发展，目前以化石燃料作为能源出现的能源储量不足、环境污染严重等问题已经成为阻碍社会经济发展的一大障碍。可再生的电能是最有希望代替化石燃料成为新一代的能源主体。而在电能的利用过程中电极材料的导电性是决定电化学性能的关键。异质纳米结构是由两种不同半导体材料结合而形成的结构。由于两种材料导电性的差异，在纳米界面处形成的电势差会提高这种复合结构的导电性。. 本项目主要围绕着异质纳米结构的构筑和电化学性能研究而展开。以相应的过渡金属氧化物或者过渡金属-有机杂化物作为模板，经过一系列反应得到异质纳米材料。本项目共构筑三种异质纳米材料： (1) 两种物质混合煅烧得到的C3N4修饰的Co3O4超薄多孔纳米片在电解水析氧反应中显示出较高的电化学活性(过电位166 mV)和稳定性(190 mA cm-2保持50 h)；(2) 三金属共沉淀-硒化获得的CoFe2Se4/NiCo2Se4杂化纳米管存在着大量纳米界面，其作为电解水析氧的阳极催化剂，表现出优于CoFe2Se4和NiCo2Se4的电化学性能(过电位224 mV)；(3) 用惰性氛围硫化制备的Co0.5Ni0.5S2-C双壳多孔微米球制作的不对称超级电容器具有较大的能量密度(64.85 Wh kg-1)。本项目为开发具有高电化学性能和稳定性的异质纳米材料提供新的设计思路和方案。