The roles of silver ions and halides (chloride, bromide,
and iodide) in the seed-mediated synthesis of gold nanostructures
have been investigated, and their influence on the growth of 10
classes of nanoparticles that differ in shape has been determined.
We systematically studied the effects that each chemical component
has on the particle shape, on the rate of particle formation, and on the
chemical composition of the particle surface. We demonstrate that
halides can be used to (1) adjust the reduction potential of the gold
ion species in solution and (2) passivate the gold nanoparticle surface,
both of which control the reaction kinetics and thus enable the
selective synthesis of a series of different particle shapes. We also
show that silver ions can be used as an underpotential deposition
agent to access a different set of particle shapes by controlling growth
of the resulting gold nanoparticles through surface passivation (more
so than kinetic effects). Importantly, we show that the density of silver coverage can be controlled by the amount and type of
halide present in solution. This behavior arises from the decreasing stability of the underpotentially deposited silver layer in the
presence of larger halides due to the relative strengths of the Ag+/Ag0−halide and Au+/Au0−halide interactions, as well as the
passivation effects of the halides on the gold particle surface. We summarize this work by proposing a set of design considerations
for controlling the growth and final shape of gold nanoparticles prepared by seed-mediated syntheses through the judicious use of
halides and silver ions.
The roles of silver ions and halides (chloride, bromide,and iodide) in the seed-mediated synthesis of gold nanostructureshave been investigated, and their influence on the growth of 10classes of nanoparticles that differ in shape has been determined.We systematically studied the effects that each chemical componenthas on the particle shape, on the rate of particle formation, and on thechemical composition of the particle surface. We demonstrate thathalides can be used to (1) adjust the reduction potential of the goldion species in solution and (2) passivate the gold nanoparticle surface,both of which control the reaction kinetics and thus enable theselective synthesis of a series of different particle shapes. We alsoshow that silver ions can be used as an underpotential depositionagent to access a different set of particle shapes by controlling growthof the resulting gold nanoparticles through surface passivation (moreso than kinetic effects). Importantly, we show that the density of silver coverage can be controlled by the amount and type ofhalide present in solution. This behavior arises from the decreasing stability of the underpotentially deposited silver layer in thepresence of larger halides due to the relative strengths of the Ag+/Ag0−halide and Au+/Au0−halide interactions, as well as thepassivation effects of the halides on the gold particle surface. We summarize this work by proposing a set of design considerationsfor controlling the growth and final shape of gold nanoparticles prepared by seed-mediated syntheses through the judicious use ofhalides and silver ions.
การแปล กรุณารอสักครู่..
