Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), UMR CNRS 7285, Equipe "Catalyse et Milieux Non Conventionnels," Université de Poitiers, 4 rue Michel Brunet, TSA 51106, 86073 Poitiers Cedex 9, France.
Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario K7L 3N6, Canada.
Sci Adv. 2017 Feb 3;3(2):e1600542. doi: 10.1126/sciadv.1600542. eCollection 2017 Feb.
We report new results for electrochemical H adsorption on and absorption in octahedral palladium nanoparticles (Pd-NPs) with an average tip-to-tip size of 7.8 nm and a narrow size distribution. They reveal a very high H loading of 0.90 that cannot be achieved using bulk Pd materials or larger NPs; this behavior is assigned to a combination of two factors: their small size and face morphology. Temperature-dependent cyclic voltammetry (CV) studies in the range of 296 to 333 K reveal unique features that are attributed to electrochemical H adsorption, H absorption, and H generation. The CV features are used to prepare H adsorption and absorption isotherms that are then used in thermodynamic data analysis. Modeling of the experimental results demonstrates that, upon H adsorption and absorption, Pd-NPs develop a core-shell-skin structure, each with its unique H loading. The electrochemical results obtained for octahedral Pd-NPs are compared to analogous data obtained for cubic Pd-NPs with a similar size as well as for larger cubic Pd-NPs and bulk materials under gas-phase conditions.
我们报告了在平均尖端到尖端尺寸为 7.8nm 且尺寸分布较窄的八面体钯纳米粒子 (Pd-NPs) 上电化学 H 吸附和吸收的新结果。它们显示出非常高的 H 负载量 0.90，这是使用体相 Pd 材料或更大的 NPs 无法实现的；这种行为归因于两个因素的结合：它们的小尺寸和面形态。在 296 至 333 K 的温度范围内进行的循环伏安 (CV) 研究揭示了独特的特征，这些特征归因于电化学 H 吸附、H 吸收和 H 生成。CV 特征用于制备 H 吸附和吸收等温线，然后用于热力学数据分析。对实验结果的建模表明，在 H 吸附和吸收后，Pd-NPs 形成了具有独特 H 负载量的核壳皮结构。对于在气相条件下具有类似尺寸的八面体 Pd-NPs 以及更大的立方 Pd-NPs 和体相材料，获得的电化学结果与类似数据进行了比较。
