【摘要】 以K2PdCl4/K2Ni(CN)4为前驱体制备了具有凝胶特性的氰胶(Cyanogels),利用硼氢化钠还原氰胶得到三维多孔珊瑚状PdNi合金前驱体,在此基础上通过原位Galvanic置换反应,制备得到内核为PdNi合金、表面具有不同厚度Au层的三维多孔PdNi@Au催化剂. X射线衍射(XRD)分析和透射电子显微镜(TEM)观测结果显示,该三维网状结构由粒径约7 nm的纳米颗粒相互连接形成;能量分散光谱(EDX)线性扫描和元素分布(Mapping)分析显示该催化剂具有典型的核壳结构.电化学测试结果表明,表面Au层的厚度影响PdNi@Au催化剂的性能,当Au的含量(摩尔分数)为5. 6%时,催化剂显示出对甲酸最佳的电催化活性,对甲酸电催化氧化的峰电流密度达到商业化铂黑催化剂的7. 2倍.更多还原

【Abstract】 K2 PdCl4 and K2 Ni(CN)4 were employed as precursors to fabricate cyanogel,which was then reduced by Na BH4 to prepare 3 D porous coral-like PdNi alloy. On the basis of the synthesized PdNi alloy,3 D porous PdNi@ Au catalysts with PdNi alloy as inner core and Au layers of different thickness on the surface were synthesized by in situ Galvanic replacement between PdNi alloy and HAu Cl4 aqueous solution. X-Ray diffraction(XRD) and transmission electron microscopy(TEM) indicated that the 3 D network structure was composed of interconnected nanoparticles with diameter of 7 nm. Energy dispersive X-ray(EDX) line scanning and mapping could declare its typical core-shell structure. Electrochemical measurements demonstrated that the electro-catalytic performance of PdNi@ Au catalysts could be affected by the thickness of Au layer. When the content of Au reached a value of 5. 6%(molar fraction),PdNi @ Au catalyst exhibited the best catalytic performance for formic acid electro-oxidation. In this case,the peak current density of PdNi@ Au catalyst was7. 2 times that of commercial Pd black.更多还原