Three-dimensional distribution and binding properties of surfactants on palladium nanoparticle surfaces

Abstract

Designing suitable nanoparticles has great importance in commercializing nanoparticle catalysts because their catalytic performances are highly depend on their shape and size. Surfactant is the organic material which is frequently used to synthesize nanoparticles. It has a great influence on the properties of particles, such as controlling the shape of nanoparticles or preventing agglomeration. However, due to its small size and complex structure, no direct analysis of their three-dimensional distribution is performed. In this study, we presented a synthesis method of palladium multiply twinned nanoparticles with high yield and excellent stability, and observed the surfactants distributed around the particles in three dimensions using atom probe tomography, which is specialized for three-dimensional atomic scale analysis. In addition, we revealed binding structure of the cetrimonium surfactants on nanoparticle surfaces by using FT-IR, NMR, TGA, and zeta potential analysis. This study is expected to provide the fundamental principles for designing nanoparticles for the intended use.