The colloidal synthesis of nanoparticles is one of the most promising, tunable methods to control the size, shape, and composition. However, the a priori design of nanoparticles of desired sizes and shapes remains a grand challenge and a trial-and-error approach is still often employed. In this work, we will present our recent efforts on integration of thermodynamics, kinetics and advanced in situ characterization measurements to develop a methodology for enabling the a priori design of metal colloidal nanoparticles with specific sizes and shapes. A novel approach combining microfluidics with in situ X-ray absorption spectroscopy (XAS) and in situ small angle X-ray scattering (SAXS) is used to develop predictive kinetic models for the synthesis of Pd colloidal nanoparticles. Using in situ SAXS, XAS and in situ liquid-stage scanning transmission electron microscopy (STEM), we show that the Pd nanoparticles synthesis does not follow a classical nucleation and growth mechanism, and the strong interaction with capping ligands result in “continuous nucleation and arrested growth”. The implications of this growth mechanism will be discussed from the perspective of kinetic model development and its predictions. The use of isothermal titration calorimetry to measure the thermodynamics of the molecular interactions between the metal (precursor and nanoparticles), solvent and ligands to ensure thermodynamic consistency of the model and enable predictions of the nanoparticle size will also be presented.

Colloidal Pd nanoparticles design: In situ characterization combined with kinetic modeling

251st National Meeting (2016)

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