nl5b04541_si_001.pdf (3.61 MB)
Quantifying the Nucleation and Growth Kinetics of Microwave Nanochemistry Enabled by in Situ High-Energy X‑ray Scattering
journal contribution
posted on 2016-01-13, 00:00 authored by Qi Liu, Min-Rui Gao, Yuzi Liu, John S. Okasinski, Yang Ren, Yugang SunThe
fast reaction kinetics presented in the microwave synthesis of colloidal
silver nanoparticles was quantitatively studied, for the first time,
by integrating a microwave reactor with in situ X-ray diffraction
at a high-energy synchrotron beamline. Comprehensive data analysis
reveals two different types of reaction kinetics corresponding to
the nucleation and growth of the Ag nanoparticles. The formation of
seeds (nucleation) follows typical first-order reaction kinetics with
activation energy of 20.34 kJ/mol, while the growth of seeds (growth)
follows typical self-catalytic reaction kinetics. Varying the synthesis
conditions indicates that the microwave colloidal chemistry is independent
of concentration of surfactant. These discoveries reveal that the
microwave synthesis of Ag nanoparticles proceeds with reaction kinetics
significantly different from the synthesis present in conventional
oil bath heating. The in situ X-ray diffraction technique reported
in this work is promising to enable further understanding of crystalline
nanomaterials formed through microwave synthesis.