State Key Laboratory of Electroanalytical Chemistry, Chinese Academy of Sciences, Changchun 130022, China.
Faraday Discuss. 2013;164:175-88. doi: 10.1039/c3fd00016h.
A new type of concave cubic Pd@Au core-shell nanocrystals is synthesized through a kinetically controlled growth process. Pd nanocubes of 56 nm are used as the inner core, and CTAC and Br(-) are used as the capping agent and selective adsorbent, respectively. A suitable ratio of HAuCl4 and cubic Pd seeds and the presence of Br(-) anions are critical to the growth of the concave cubic Pd@Au core-shell nanocrystals. The fast deposition rate on the corners of the cubic Pd seeds promotes the overgrowth of the Au outer shell along the <111> direction, leading to the formation of concave cubic nanostructures. The reduction process is monitored by the surface plasmon resonance spectra of the nanocrystals, and the extinction band became broader and red shifted as the nanocrystals became larger. The electrocatalytic properties of the concave cubic Pd@Au core-shell nanocrystals were investigated with the cathodic electrochemiluminescence reaction of luminol and H2O2. A possible electrocatalytic mechanism was proposed and analyzed.
一种新型凹立方 Pd@Au 核壳纳米晶体通过动力学控制生长过程合成。使用 56nm 的 Pd 纳米立方体作为内核，CTAC 和 Br(-)分别作为封端剂和选择性吸附剂。合适的 HAuCl4 和立方 Pd 种子的比例以及 Br(-)阴离子的存在对于凹立方 Pd@Au 核壳纳米晶体的生长至关重要。在立方 Pd 种子的角上的快速沉积速率促进了 Au 外壳沿着<111>方向的过度生长，导致形成凹立方纳米结构。通过纳米晶体的表面等离子体共振光谱监测还原过程，随着纳米晶体的增大，消光谱带变得更宽且红移。通过鲁米诺和 H2O2 的阴极电化学发光反应研究了凹立方 Pd@Au 核壳纳米晶体的电催化性质。提出并分析了一种可能的电催化机制。
