双金属核壳结构纳米粒子负载氮掺杂石墨烯在碱性介质中对氢氧化反应的电催化性能研究

Low-Pt or non-Pt based catalyst is a critical route to lower the cost of alkaline fuel cell. Based on its well electrocatalysis to hydrogen oxidation reaction in alkaline medium, nickel is becoming a research focus in hydroxide exchange membrane fuel cell. However, there have some problems of nano-nickel: (1) the catalytic efficiency is not high enough; (2) nano nickel is very active to be easy oxidation and passivation, and then deactivation..Oriented by the limitations of the nickel-based electrocatalyst, this project will synthesize a series of M@Ni bimetallic core-shell nanoparticles. The core-shell nanoparticles will take different electronegativity metals (Au, Mo or Cu) as core and Ni as shell, and then support on nitrogen-doped graphene. The core metal in the M@Ni core-shell nanoparticles will regulate the electronic structure of nickel surface. We will explore the influence of the core electronegativity to reactivity of nickel d-orbitals. Therefore, it will selective inhibit the d-orbitals reactivity of nickel, increase interaction of nickel and hydrogen, meanwhile weaken interaction of nickel and oxygen. In addition, the nitrogen-doped graphene also has synergistic effect through modulating of the Ni d-orbitals. Above all, it will improve its electrocatalytic performance, and also improve its oxidation and deactivation defects of nickel. Through regulating the microstructure of the bimetallic core-shell nanoparticles, screen out Ni-based electrocatalyst which suitable for alkaline medium with stable performance and high catalytic efficiency.

发展低铂或非铂基电催化剂是降低碱性燃料电池成本的重要途径。金属镍因其在碱性介质中对氢氧化反应具有良好的电催化作用而成为研究热点，但其催化效率不够高，且纳米镍非常活泼，表面易氧化、钝化、失活。.项目以镍基电催化剂存在的局限性为导向，以三种电负性不同的金属M(Au，Mo，Cu)为内核材料，拟合成一系列M@Ni双金属核壳纳米粒子，将其负载于氮掺杂石墨烯。通过内核金属调控镍表面电子结构，探究不同电负性的内核金属对镍d带反应活性的影响，选择性抑制镍的d带反应性，增强镍与氢的相互作用，减弱镍与氧的相互作用；结合氮掺杂石墨烯调节镍d轨道的协同作用，既提高纳米镍的电催化性能，又改善其易氧化失活的缺陷。调控双金属核壳纳米粒子的微观结构，筛选出性能稳定、催化效率高、适用于碱性介质中阳极氢氧化反应的镍基电催化剂，解决碱性介质中阳极电催化剂的瓶颈问题。

发展低铂或非铂基电催化剂是降低碱性燃料电池成本的重要途径。金属镍在碱性介质中对阳极氧化反应具有良好的电催化作用而成为研究热点，但其催化效率不够高，稳定性也有待提高。项目以镍基电催化剂存在的局限性为导向，结合氮掺杂碳材料的协同作用，提高纳米镍的电催化性能，改善其稳定性。解决碱性介质中阳极电催化剂的关键问题。.在此背景下，本项目合成了一系列镍基纳米粒子负载氮掺杂碳纳米复合材料：Au@Ni-rGO核壳纳米复合材料、NiO/Ni-N/C复合材料、花状N-C/NiO纳米复合材料、镍纳米颗粒/丝瓜络衍生氮掺杂多孔碳纳米复合材料(NiNPs/T‑dNPCN)等。优化合成条件，对所合成的纳米复合材料进行形貌、结构及性能表征。探讨合成材料的电化学性能及在碱性条件下对燃料电池阳极氧化反应的电催化性能，初步探讨电催化机理。.实验结果表明，本项目合成的Au@Ni-rGO、NiO/Ni-N/C、花状N-C/NiO、NiNPs/T‑dNPCN具有良好的电化学性能，具有较大的电化学活性表面积。Au@Ni-rGO、NiO/Ni-N/C、花状N-C/NiO在碱性条件下对阳极氢氧化反应具有一定的电催化作用，催化效果还有提升空间。Au@Ni-rGO、NiO/Ni-N/C、花状N-C/NiO、NiNPs/T‑dNPCN在碱性条件下对阳极甲醇氧化反应具有较好的电催化性能，且具有良好的电化学稳定性。.综上所述，本项目发展了一系列价格低廉、催化效率高、性能稳定的镍基纳米粒子负载氮掺杂碳纳米复合材料，有望用作燃料电池阳极电催化剂，对解决燃料电池在碱性介质中阳极氧化反应的电催化剂具有重要意义。