Beijing National Laboratory for Molecular Sciences, Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences , Beijing, 100190, China.
ACS Appl Mater Interfaces. 2013 Nov 13;5(21):11471-8. doi: 10.1021/am403996d. Epub 2013 Oct 25.
This study describes an effective method to prepare highly dispersed palladium nanoparticles supported onto single-walled carbon nanotubes (SWNTs) with high electrocatalytic activity toward the oxidation of ethanol. This method is essentially based on electrochemical post-treatment of Pd-based infinite coordination polymer (ICP). The Pd-based ICP is synthesized through the coordination reaction between Zn(2+) and metallo-Schiff base (MSB) to form Zn-MSB-Zn (ZMZ) ICP that precipitates from ethyl ether. The as-formed Zn-MSB-Zn ICP is then subjected to an ion-exchange reaction with Pd(2+) to obtain the Zn-MSB-Pd (ZMP) ICP. To prepare Pd/SWNT nanocomposite, the ZMP ICP is mixed into the SWNT dispersion in N-dimethylformamide (DMF) to form a homogeneous dispersion that is then drop-coated onto a glassy carbon (GC) electrode. Electrochemical post-treatment of ZMP ICP to form Pd/SWNT nanocomposite is thus performed by polarizing the coated electrode at -0.2 V for 600 s in 0.5 M H2SO4. The results obtained with scanning electron microscopy (SEM) and transmission electron microscopy (TEM) reveal that the resulting Pd nanoparticles are highly dispersed onto SWNTs and the particles size are small and narrowly distributed (2.12 ± 0.32 nm). X-ray photoelectron spectroscopy (XPS) analysis shows that, after the electrochemical post-treatment, no detectable ZMP ICP precursors are left on the surface of SWNTs. The electrocatalytic activity of the as-formed Pd/SWNT nanocomposite toward ethanol oxidation is investigated by cyclic voltammetry and chronoamperometry. The results show that the Pd/SWNT nanocomposite prepared here shows a more negative potential and higher mass catalytic activity, as well as higher stability for the oxidation of ethanol than the commercial Pd/C catalyst. This work demonstrates a novel approach to the formation of ultrasmall and highly dispersed Pd/SWNT nanocomposite with enhanced electrocatalytic activity toward ethanol oxidation.
这项研究描述了一种有效方法，用于制备高度分散的负载在单壁碳纳米管（SWNTs）上的钯纳米粒子，该粒子对乙醇氧化具有高电催化活性。该方法本质上基于 Pd 基无限配位聚合物（ICP）的电化学后处理。Pd 基 ICP 通过 Zn(2+)与金属-Schiff 碱（MSB）的配位反应合成，形成从乙醚中沉淀出来的 Zn-MSB-Zn（ZMZ）ICP。然后，所形成的 Zn-MSB-Zn ICP 与 Pd(2+)进行离子交换反应，得到 Zn-MSB-Pd（ZMP）ICP。为了制备 Pd/SWNT 纳米复合材料，将 ZMP ICP 混入 SWNT 在 N-二甲基甲酰胺（DMF）中的分散体中，形成均匀的分散体，然后将其滴涂到玻璃碳（GC）电极上。通过在 0.5 M H2SO4 中在-0.2 V 下极化涂覆的电极 600 s 来进行 ZMP ICP 的电化学后处理以形成 Pd/SWNT 纳米复合材料。扫描电子显微镜（SEM）和透射电子显微镜（TEM）的结果表明，所得的 Pd 纳米粒子高度分散在 SWNTs 上，并且粒子尺寸小且分布狭窄（2.12±0.32nm）。X 射线光电子能谱（XPS）分析表明，电化学后处理后，SWNTs 表面上没有检测到可检测的 ZMP ICP 前体。通过循环伏安法和计时安培法研究了所形成的 Pd/SWNT 纳米复合材料对乙醇氧化的电催化活性。结果表明，与商业 Pd/C 催化剂相比，此处制备的 Pd/SWNT 纳米复合材料对乙醇氧化具有更负的电位、更高的质量催化活性和更高的稳定性。这项工作展示了一种形成具有增强的乙醇氧化电催化活性的超小且高度分散的 Pd/SWNT 纳米复合材料的新方法。
