Ultrasmall
Au, Pd, and AuPd nanoparticles (NPs) stabilized by PVP
were prepared in a microfluidic reactor with cyclone micromixers for
rapid mixing of reactants. In this system, pulsation-free flow of
reactants was achieved at a total flow rate of 2.6 L h–1. A rapid homogeneous mixing within 2 ms was obtained with three
cyclone micromixers. Controlled NP nucleation and growth occur in
a following meandering microchannel. The resulting colloidal NPs were
characterized thoroughly by various complementary techniques, e.g.,
high-resolution transmission electron microscopy (HRTEM), energy-dispersive
X-ray spectroscopy (EDX), and ultraviolet–visible spectroscopy.
The average NP diameter was about 1 nm with a narrow size distribution,
and electron microscopy showed homogeneously alloyed NPs. Moreover,
the particles were supported on TiO2 for catalytic tests
and further structural characterization. Electron microscopy showed
a uniform distribution of NPs on the support with some aggregation.
X-ray absorption spectroscopy (XAS) confirmed the formation of well-mixed
AuPd alloys in NP cores with Pd-rich surfaces. Finally, 1 wt % metal-loaded
supports showed catalytic activities in CO oxidation in the following
order: Au/TiO2 ≥ Au
x
Pd
y
/TiO2 ≥ Pd/TiO2. Hence, the physical and chemical properties of these catalysts
can be fine-tuned.
For the first time the formation and decay of the thermally very sensitive bis(μ-oxo)dicopper species was monitored at ambient temperature in a continuous flow setup and the rate constant of the decay was measured.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.