Department of Chemistry and Nano Science, Ewha Womans University, Seoul, Korea.
Phys Chem Chem Phys. 2012 Mar 21;14(11):3974-9. doi: 10.1039/c2cp23429g. Epub 2012 Feb 9.
The electrocatalytic activities of nanoporous palladium (npPd) and platinum (npPt) for oxygen reduction reaction (ORR) under alkaline conditions and hydrogen peroxide electrochemical reactions under neutral conditions were examined. npPd and npPt were prepared by the electrochemical deposition of each metal from the corresponding metal precursor in the presence of reverse micelles of Triton X-100, directing highly porous microstructures. The nanoporous catalysts showed excellent electrocatalytic activity for both the ORR and hydrogen peroxide electrochemical oxidation/reduction due to the increased active surface area. In particular, the npPd exhibited superior ORR activity (i.e., more positive onset and half-wave potentials, higher current density and greater number of electrons transferred) despite the smaller roughness factor than the npPt and commercial Pt. The catalytic activity for the hydrogen peroxide electrochemical reactions was also higher while using npPd (i.e., faster electrode reaction kinetics, increased current densities, etc.) compared to npPt. The higher catalytic activity of npPd than that of npPt suggests an advantage of the unique npPd structure, composed of nano- as well as micro-porosity, in facilitating mass transport through the porous metal layer. The npPd exhibited amperometric current responses, induced by the oxidation as well as reduction of hydrogen peroxide, linearly proportional to the hydrogen peroxide concentration with a rapid response time (<~2 s), high sensitivity, and low detection limit (<1.8 μM).
研究了纳米多孔钯（npPd）和铂（npPt）在碱性条件下对氧还原反应（ORR）的电催化活性，以及在中性条件下对过氧化氢电化学反应的电催化活性。npPd 和 npPt 是通过在 Triton X-100 反向胶束存在的情况下，从相应的金属前体制备的，分别对两种金属进行电化学沉积，从而得到具有高度多孔微观结构的纳米多孔催化剂。由于增加了活性表面积，纳米多孔催化剂对 ORR 和过氧化氢电化学氧化/还原均表现出优异的电催化活性。特别是 npPd 尽管比 npPt 和商业 Pt 的粗糙度系数小，但表现出更高的 ORR 活性（即更正的起始和半波电位、更高的电流密度和更大的电子转移数）。与 npPt 相比，npPd 用于过氧化氢电化学反应的催化活性也更高（即更快的电极反应动力学、更高的电流密度等）。npPd 比 npPt 具有更高的催化活性，这表明纳米多孔钯独特的纳米和微孔结构有利于通过多孔金属层促进质量传输，从而具有优势。npPd 对过氧化氢的氧化和还原均产生了安培响应，与过氧化氢浓度呈线性比例关系，具有快速的响应时间（<~2 s）、高灵敏度和低检测限（<1.8 μM）。
