碳包裹过渡金属碳化物纳米晶的可控合成与催化应用

Carbon wrapped transition metal carbide nanocrystal has received considerable research interests recently due to its high catalytic activity toward oxygen reduction. To realize the controllable synthesis of the carbon wrapped transition metal carbide nanocrystal, which could not be achieved with most of the existing methods, we propose to use a new precursor: the transition metal-phenol complexes, for the preparation process. It is expected that carbon wrapped transition metal carbide nanocrystal with well-defined morphology and controlled composition could be obtained through appropriate matching of phenol with transition metal ions and control over the carbonization process. The produced catalyst will be screened in terms of their oxygen reduction catalytic activity and stability under the operating condition of proton exchange membrane fuel cell. Based on these results, the relationship between the catalysts’ structural and compositional characteristics with their catalytic performance will be established. In addition, the affinity of phenols with substrates of different materials will be used for the construction of phenol coated 1D transition metal oxide nanostructures, which will be later converted to the carbon coated 1D transition metal carbide nanostructures by controlled carbonization. This novel catalytic structure is anticipated to possess high catalytic activity as well as ordered pathways for mass transfer and electron transportation. We envision that the novel materials we propose could provide key material support for the development of novel fuel cell electrocatalyst.

碳包裹过渡金属碳化物纳米晶以其良好的氧还原催化能力在近期得到了广泛的研究关注。针对该类材料的传统制备方法难以对过渡金属碳化物纳米晶的尺寸及分布进行控制的问题，本项目拟使用过渡金属-酚类配合物为前驱体，通过酚类物质与过渡金属离子的匹配、碳化过程的控制以实现碳包裹过渡金属碳化物纳米晶的可控合成；详细研究该类材料在质子交换膜燃料电池工作环境下的氧还原催化性能及稳定性，获得具有高氧还原催化能力的碳包裹过渡金属碳化物纳米晶材料，并以此为基础构建该类催化剂的成分结构与催化活性的构效关系。同时，本项目拟利用酚类物质与不同材料表面的亲和性，使用过渡金属-酚类配合物对过渡金属氧化物一维纳米结构进行表面涂层修饰与碳化还原，以制备兼具高氧还原活性及有序传质与电子传输结构的氧还原催化剂,为质子交换膜燃料电池电催化剂的开发提供关键材料支撑。

降低催化材料的成本是实现质子交换膜燃料电池等新型能源转化器件商业化的迫切需要。针对这一需求，本项目按照研究计划，主要开展了新型氧还原（ORR）、析氧（OER）、析氢（HER）反应催化材料的研究，取得了一些进展和初步结果：（1）合成了一系列过渡金属-酚类物质配合物，并以其为前驱体制备了过渡金属掺杂的高效ORR催化材料；（2）通过控制前驱体的碳化合成条件，得到了基于碳化铁及氧化铁活性组分的ORR催化剂；（3）以离子液体为前驱体，硅球为模板合成了N, S共掺杂碳催化材料，发现杂原子的可控掺杂与有效传质结构的构建可增强材料的ORR活性；（4）通过对离子液体前驱体成分的设计，实现了无模板掺杂型碳催化材料的合成，得到了对ORR, OER均有高催化活性的催化材料；（5）以基于酚醛树脂前驱体的有序介孔碳为载体，合成得到了具有低载量高活性的Pt/C催化材料。同时，以在上述研究中总结得到的新能源器件对电极、电解质材料的共性需求及构效关系为基础，展开了对锂二次电池隔膜材料的研究，通过物理修饰和化学改性制备了一系列的低成本高性能的聚合物基隔膜材料。