Nickel-Cerium Layered Double Hydroxide as Electrocatalyst for Glycerol Oxidation

A new nickel based layered double hydroxide nanomaterial, Ni0.8Ce0.2-LDH, constituted by about 3 nm large nanoparticles exhibiting enhanced electrocatalytic properties towards oxidation of glycerol in alkaline media, was prepared by incorporation of 20 wt.% of CeIII ions into α-nickel hydroxide. This can be oxidized to CeIV, as demonstrated by X-ray photoelectron spectroscopy, a much electron withdrawing and oxidizing species responsible for electronic interactions and additional electrocatalytic active sites giving rise to synergic effects. High-resolution transmission electron microscopy images and the X-ray diffractograms indicated a material with a significantly lower size and degree of crystallinity than α-Ni(OH)2, one of the factors contributing to its enhanced electrochemical and electrocatalytic activity, as demonstrated by cyclic voltammetry and electrochemical impedance spectroscopy, suggesting a good potentiality for development of glycerol fuel cells.

本研究通过向α-氢氧化镍中掺入20 wt.%的三价铈（CeIII）离子，制备得到一种新型镍基层状双氢氧化物（nickel-based layered double hydroxide, LDH）纳米材料Ni₀.₈Ce₀.₂-LDH。该材料由粒径约3 nm的纳米颗粒构成，在碱性介质中对甘油氧化反应表现出增强的电催化性能。经X射线光电子能谱（X-ray photoelectron spectroscopy, XPS）表征证实，材料中的CeIII可被氧化为四价铈（CeIV）；四价铈作为强吸电子且强氧化性的物种，可通过电子相互作用与额外的电催化活性位点产生协同效应。高分辨透射电子显微镜（high-resolution transmission electron microscopy, HRTEM）成像与X射线衍射图谱分析结果显示，该材料的粒径与结晶度均显著低于α-氢氧化镍（α-Ni(OH)₂）；结合循环伏安法与电化学阻抗谱（electrochemical impedance spectroscopy, EIS）的表征结果，这一特征是其电化学与电催化性能提升的关键因素之一，表明该材料在甘油燃料电池开发领域具备良好的应用潜力。