Instituto de Electroquímica, Universidad de Alicante, Ap. 99, 03080 Alicante, Spain.
Phys Chem Chem Phys. 2012 Aug 7;14(29):10258-65. doi: 10.1039/c2cp40992e. Epub 2012 Jun 21.
The electrocatalytic properties of palladium nanocubes towards the electrochemical oxidation of formic acid were studied in H(2)SO(4) and HClO(4) solutions and compared with those of spherical Pd nanoparticles. The spherical and cubic Pd nanoparticles were characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The intrinsic electrocatalytic properties of both nanoparticles were shown to be strongly dependent on the amount of metal deposited on the gold substrate. Thus, to properly compare the activity of both systems (spheres and nanocubes), the amount of sample has to be optimized to avoid problems due to a lower diffusion flux of reactants in the internal parts of the catalyst layer resulting in a lower apparent activity. Under the optimized conditions, the activity of the spheres and nanocubes was very similar between 0.1 and 0.35 V. From this potential value, the activity of the Pd nanocubes was remarkably higher. This enhanced electrocatalytic activity was attributed to the prevalence of Pd(100) facets in agreement with previous studies with Pd single crystal electrodes. The effect of HSO(4)(-)/SO(4)(2-) desorption-adsorption was also evaluated. The activity found in HClO(4) was significantly higher than that obtained in H(2)SO(4) in the whole potential range.
研究了钯纳米立方体在 H(2)SO(4)和 HClO(4)溶液中对甲酸电化学氧化的电催化性能，并与球形 Pd 纳米粒子进行了比较。球形和立方钯纳米粒子通过透射电子显微镜（TEM）和 X 射线衍射（XRD）进行了表征。两种纳米粒子的本征电催化性能强烈依赖于沉积在金基底上的金属量。因此，为了正确比较两种体系（球体和纳米立方体）的活性，必须优化样品量，以避免由于反应物在催化剂层内部扩散通量较低而导致的表观活性较低的问题。在优化条件下，球体和纳米立方体在 0.1 到 0.35 V 之间的活性非常相似。从这个电位值开始，钯纳米立方体的活性显著提高。这种增强的电催化活性归因于与 Pd 单晶电极的先前研究一致的 Pd(100)面的优势。还评估了 HSO(4)(-) / SO(4)(2-)解吸-吸附的影响。在整个电位范围内，在 HClO(4)中发现的活性明显高于在 H(2)SO(4)中获得的活性。
