Materials Science Institute and Inorganic Chemistry Department, Alicante University , Ap. 99, E-03080 Alicante, Spain.
Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University , 2-1 Yamada-oka, Suita, Japan.
Langmuir. 2016 Nov 22;32(46):12110-12118. doi: 10.1021/acs.langmuir.6b03149. Epub 2016 Nov 7.
Palladium nanoparticles (Pd NPs) were synthesized by the reduction-by-solvent method using polyvinylpirrolidone (PVP) as capping agent. The nonstatic interaction between PVP and the metallic surface may change the properties of the NPs due to the different possible interactions, through either the O or N atoms of the PVP. In order to analyze these effects and their repercussions in their catalytic performance, Pd NPs with various PVP/Pd molar ratios (1, 10, and 20) were prepared, deposited on silica, and tested in the formic acid decomposition reaction. The catalytic tests were conducted using catalysts prepared by loading NPs with three different time lapses between their purification and their deposition on the silica support (1 day, 1 month, and 6 months). CO adsorption, FTIR spectroscopy, XPS, and TEM characterization were used to determine the accessibility of the Pd NPs surface sites, the electronic state of Pd, and the average NPs size, respectively. The H production from the formic acid decomposition reaction has a strong dependence on the Pd surface features, which in turn are related to the NPs aging time due to the progressive removal of the PVP.
钯纳米粒子 (Pd NPs) 通过溶剂还原法合成，使用聚乙烯吡咯烷酮 (PVP) 作为封端剂。PVP 与金属表面之间的非静电力相互作用可能会改变 NPs 的性质，这是由于 PVP 中的 O 或 N 原子与金属表面之间可能存在不同的相互作用。为了分析这些相互作用及其对催化性能的影响，我们制备了具有不同 PVP/Pd 摩尔比（1、10 和 20）的 Pd NPs，将其沉积在二氧化硅上，并在甲酸分解反应中进行测试。通过在将 NPs 纯化和沉积到二氧化硅载体上之间的三个不同时间间隔（1 天、1 个月和 6 个月）来制备催化剂，进行了催化测试。使用 CO 吸附、傅里叶变换红外光谱 (FTIR)、X 射线光电子能谱 (XPS) 和透射电子显微镜 (TEM) 对催化剂进行了表征，以确定 Pd NPs 表面位的可及性、Pd 的电子态以及平均 NPs 尺寸。甲酸分解反应中产生的 H2 产量强烈依赖于 Pd 表面特性，而这又与 NPs 的老化时间有关，因为 PVP 会逐渐被去除。
