Characterizations of Surface Ligands and Stabilizers on Metallic Nanoparticles

Despite the well-established techniques to characterize the core structure and composition of metallic nanoparticles (NPs), the characterizations of surface stabilizers on metallic NPs remain very challenging. Such NPs are active catalysts for the hydrogenation of alkene, alkyne, aromatic, nitro, ketone, and aldehyde groups. The stabilizers affect the size, solubility, stability, and catalytic activity of NPs. A variety of stabilizers have been characterized using infrared spectroscopy (IR), NMR, elemental analysis, X-ray photoelectron microscopy, energy-dispersive X-ray spectroscopy, thermogravimetric analysis, and mass spectrometry. These stabilizers include carbonyl, phosphine, N-heterocyclic carbene, amine, aniline, thiolate, citrate, and phosphine oxide. This chapter focuses on developments for the qualitative and quantitative analyses of NP stabilizers, which are discrete molecules or ions.