Synthesis of flower-like gold nanoparticles and their electrocatalytic activity towards the oxidation of methanol and the reduction of oxygen
Synthesis of flower-like gold nanoparticles and their electrocatalytic activity towards the oxidation of methanol and the reduction of oxygen
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DOI：
10.1021/la063243z
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发表时间：
2007-03-27
期刊：
影响因子：
3.9
通讯作者：
Raj, C. Retna
中科院分区：
文献类型：
--
作者：
Jena, Bikash Kumar;Raj, C. Retna
本文介绍了枝状花状金（Au）纳米晶的合成及其对甲醇氧化和氧气还原的电催化活性。使用N-2-羟乙基哌嗪-N-2-乙磺酸（HEPES）作为还原/稳定剂，通过一锅合成法获得金纳米花（GNF）。通过紫外-可见光谱、透射电子显微镜（TEM）、X射线衍射（XRD）和电化学测试对纳米纤维进行了表征。紫外-可见光谱显示两个频带对应的横向和纵向表面等离子体（SP）吸收在532和720 nm处，分别为胶体GNF。GNF自组装在溶胶-凝胶衍生的硅酸盐网络上，该网络预组装在多晶Au电极上并用于电催化应用。的GNF保留其形态的硅酸盐网络上的GNF的紫外-可见漫反射光谱（DRS）的硅酸盐网络上显示的纵向和横向带的胶体GNF的情况下。GNF对甲醇的氧化和氧气的还原具有良好的电催化活性。甲醇在碱性溶液中的氧化被观察到在类似于0.245 V，这是比未改性的多晶金电极少得多的积极。在中性pH下，在GNF电极上观察到氧气还原为H2 O2和H2 O2进一步还原为水。GNF的电催化活性显著高于球形柠檬酸盐稳定的Au纳米颗粒（SGNs）。
This article describes the synthesis of branched flower-like gold (Au) nanocrystals and their electrocatalytic activity toward the oxidation of methanol and the reduction of oxygen. Gold nanoflowers (GNFs) were obtained by a one-pot synthesis using N-2-hydroxyethylpiperazine-N-2-ethanesulphonic acid (HEPES) as a reducing/stabilizing agent. The GNFs have been characterized by UV-visible spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), and electrochemical measurements. The UV-visible spectra show two bands corresponding to the transverse and longitudinal surface plasmon (SP) absorption at 532 and 720 nm, respectively, for the colloidal GNFs. The GNFs were self-assembled on a sol-gel-derived silicate network, which was preassembled on a polycrystalline Au electrode and used for electrocatalytic applications. The GNFs retain their morphology on the silicate network; the UV-visible diffuse reflectance spectra (DRS) of GNFs on the silicate network show longitudinal and transverse bands as in the case of colloidal GNFs. The GNFs show excellent electrocatalytic activity toward the oxidation of methanol and the reduction of oxygen. Oxidation of methanol in alkaline solution was observed at similar to 0.245 V, which is much less positive than that on an unmodified polycrystalline gold electrode. Reduction of oxygen to H2O2 and the further reduction of H2O2 to water in neutral pH were observed at less negative potentials on the GNFs electrode. The electrocatalytic activity of GNFs is significantly higher than that of the spherically shaped citrate-stabilized Au nanoparticles (SGNs).