title: Shape-controlled continuous synthesis of metal nanostructures.
abstract: A segmented flow-based microreactor is used for the continuous production of faceted nanocrystals. Flow segmentation is proposed as a versatile tool to manipulate the reduction kinetics and control the growth of faceted nanostructures; tuning the size and shape. Switching the gas from oxygen to carbon monoxide permits the adjustment in nanostructure growth from 1D (nanorods) to 2D (nanosheets). CO is a key factor in the formation of Pd nanosheets and Pt nanocubes; operating as a second phase, a reductant, and a capping agent. This combination confines the growth to specific structures. In addition, the segmented flow microfluidic reactor inherently has the ability to operate in a reproducible manner at elevated temperatures and pressures whilst confining potentially toxic reactants, such as CO, in nanoliter slugs. This continuous system successfully synthesised Pd nanorods with an aspect ratio of 6; thin palladium nanosheets with a thickness of 1.5 nm; and Pt nanocubes with a 5.6 nm edge length, all in a synthesis time as low as 150 s.
authors.affiliation: Department of Chemical Engineering, Massachusetts Institute of Technology, 77, Massachusetts Avenue, Cambridge, MA 02139, USA. kfjensen@mit.edu.
authors.forename: Victor
authors.initials: V
authors.lastname: Sebastian
authors.affiliation: Department of Chemical Engineering, Massachusetts Institute of Technology, 77, Massachusetts Avenue, Cambridge, MA 02139, USA. kfjensen@mit.edu.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Smith
authors.affiliation: Department of Chemical Engineering, Massachusetts Institute of Technology, 77, Massachusetts Avenue, Cambridge, MA 02139, USA. kfjensen@mit.edu.
authors.forename: Klavs F
authors.initials: KF
authors.lastname: Jensen