title: Quantifying the Nucleation and Growth Kinetics of Microwave Nanochemistry Enabled by in Situ High-Energy X-ray Scattering.
abstract: The 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.
authors.affiliation: Center for Nanoscale Materials and ‡X-ray Science Division, Advanced Photon Source, Argonne National Laboratory , 9700 South Cass Avenue, Argonne, Illinois 60439, United States.
authors.forename: Qi
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Center for Nanoscale Materials and ‡X-ray Science Division, Advanced Photon Source, Argonne National Laboratory , 9700 South Cass Avenue, Argonne, Illinois 60439, United States.
authors.forename: Min-Rui
authors.initials: MR
authors.lastname: Gao
authors.affiliation: Center for Nanoscale Materials and ‡X-ray Science Division, Advanced Photon Source, Argonne National Laboratory , 9700 South Cass Avenue, Argonne, Illinois 60439, United States.
authors.forename: Yuzi
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Center for Nanoscale Materials and ‡X-ray Science Division, Advanced Photon Source, Argonne National Laboratory , 9700 South Cass Avenue, Argonne, Illinois 60439, United States.
authors.forename: John S
authors.initials: JS
authors.lastname: Okasinski
authors.affiliation: Center for Nanoscale Materials and ‡X-ray Science Division, Advanced Photon Source, Argonne National Laboratory , 9700 South Cass Avenue, Argonne, Illinois 60439, United States.
authors.forename: Yang
authors.initials: Y
authors.lastname: Ren
authors.affiliation: Center for Nanoscale Materials and ‡X-ray Science Division, Advanced Photon Source, Argonne National Laboratory , 9700 South Cass Avenue, Argonne, Illinois 60439, United States.
authors.forename: Yugang
authors.initials: Y
authors.lastname: Sun
keywords: Microwave nanochemistry; first-order reaction kinetics; in situ high-energy X-ray diffraction; self-catalytic reaction kinetics; silver nanoparticles