三维共连续多级孔纳米NiCoPx@NiCo/C异质结构的制备及双功能电催化性能

The bifunctional electrocatalysts are the key of H2 and O2 production of overall water splitting by electrocatalystic technology. At present, the development of bifunctional electrocatalysts is limited by its complex preparation process, low stability and relative high cost. The project focuses on the preparation of 3D cocontinuous hierarchically porous nano NiCoPx@NiCo/C heterostructure. Some scientific problems about the construction of hierarchically porous nanostructure, the fabrication of heterostructure and its electrocatalysis of overall water splitting will be solved. The key technologies of synergic controlling sol-gel transition and phase separation, pyrolysis of polymer into carbon, carbothermal reduction of Ni-Co oxides and phosphating reaction of NiCo alloys will be broken through. The 3D cocontinuous hierarchically porous nano NiCoPx@NiCo/C heterostructure can be constructed by simultaneous distribution of macroporous (>50 nm) / mesoporous (2-50 nm), nano NiCo alloys to assemble cocontinuous skeletons, in-situ composition of alloy and carbon, NiCoPx and NiCo/C to form heterostructures. The HER and OER activity and electrocatalystic performance of overall water splitting for H2 and O2 production of the resultant NiCoPx@NiCo/C heterostructure will be revealed, and the relationship between electrocatalystic performance and hierarchically porous nanostructure, heterostructure and in-situ composition of carbon will be clarifed. It will provide the theoretical basis for the fabrication of bifunctional electrocatalysts with high electrocatalystic activity, high stability and low-costy and easy to get.

双功能电催化材料是电催化全分解水制氢气和制氧气的关键。本课题针对双功能电催化材料制备工艺复杂、稳定性差、成本高等问题，开展三维共连续多级孔纳米NiCoPx@NiCo/C异质结构制备研究，解决多级孔纳米结构搭建、异质结构构建及其电催化全分解水过程有关的科学问题，突破溶胶-凝胶转化与诱导相分离协同控制、聚合物高温裂解成碳、镍-钴氧化物碳热还原及NiCo合金磷化反应等关键技术，制备大孔(>50nm)/介孔(2-50nm)同时分布、纳米NiCo合金组装共连续骨架、NiCo合金和C原位复合、NiCoPx与NiCo/C形成异质结构的三维共连续多级孔纳米NiCoPx@NiCo/C异质结构，探究异质结构的HER和OER双功能催化活性和电催化全分解水制氢气和制氧气性能，阐明多级孔纳米结构、异质结构、碳原位复合与电催化全分解水性能之间的内在规律，为高催化活性、高稳定性、低廉易得的双功能电催化材料开发奠定基础。

本项目针对全分解水用双功能电催化材料制备工艺复杂、稳定性差、成本高等问题，采用溶胶-凝胶伴随相分离、牺牲模板法、水热结合电沉积、磷化及硫化等工艺与技术，制备了具有三维共连续多级孔结构、立方纳米结构、异质结构、核壳结构的双功能电催化材料，通过溶胶-凝胶转化与诱导相分离协同控制、模板刻蚀、聚合物高温裂解成碳、过渡金属氧化物碳热还原及过渡金属氧化物/氢氧化物磷化/硫化反应等机理研究，分别搭建出三维共连续多孔二元/三元过渡金属氢氧化物/氧化物块体材料以及纳米镍钴合金/C复合材料、富缺陷立方纳米花/微米笼/中空微米笼、异质结构过渡金属硫化物/磷化物@过渡金属氢氧化物、三维核壳异质结构纳米阵列等双功能电催化材料，分析了不同独特结构的电催化材料的析氢HER和析氧OER双功能催化活性和电催化全分解水制氢气和制氧气性能，阐明了多级孔纳米结构、异质结构、富缺陷立方纳米结构、核壳结构、多元素掺杂与电催化全分解水性能之间的内在规律与协同增强效应，所制备的双功能电催化材料具有高催化活性、高稳定性、低廉易得等特点，有望取代贵金属电催化剂，成为高效稳定低成本电解水催化剂的候选材料，并推动全分解水制氢技术的发展。