Effects of preparation conditions on the morphology and performance of palladium nanostructures

Abstract

Three-dimensional palladium nanoflowers (PdNF) composed of ultrathin Pd nanosheets had been synthesized by a solvothermal approach in our previous work. Here, the effects of preparation conditions on the morphology and electrochemical performance of palladium nanostructures were investigated. The explored conditions are as follows: the ratio of reducing agent to capping agent, the concentration of PdCl2 precursor, the amount of HCl (used for PdCl2 dissolution), the reaction temperature and time. Only when these conditions are strictly controlled, the obtained Pd material displays a uniformly nanoflower-like morphology, otherwise the Pd samples with nanoparticles or incomplete flowers can only be obtained. Then, the relationship between the morphology of Pd and its electrocatalytic activity was further studied. The results indicate that the Pd with perfect nanoflowers morphology possesses superior activity for formic acid electro-oxidation, while the Pd with incomplete flowers and ordinary (or irregular) particle morphology shows moderate and inferior activity. Therefore, the morphology-dependent electrocatalytic activity has been demonstrated in this work.