Polyvinylpyrrolidone (PVP)-based silver nanoprisms (AgNPrs) show an initial stacking geometry because of their low zeta potential and electrostatic interaction between face-to-face energetically stable {111} surface-bound pyrrolidone groups through the Na + -ioninduced cation−π interaction. Congested interplanar space between AgNPrs allows As(III) to react differentially with silver atoms from facial {111} and peripheral {110} facets to result in smaller stackings and finally nanoseeds. Above this critical concentration of As(III), PVP leached out from nanoparticles to form nanoseed-engulfed emulsions and induced controlled aggregation. This entire morphological transition has been decoded by recording their surface plasmon and surfaceenhanced Raman scattering tuning and confirmed by the transmission electron microscopy study. Strong affinity and selectivity of As(III) toward the Ag atom (verified and estimated by the HF/3-21g* level of density functional theory calculation) coupled with low-cost colorimetry provide us a versatile assay with potential application in the environmental protection drive.
Spherical
gold nanoseed (∼5–6 nm)-induced (but not seed-mediated)
silver nanorods (Hy-Au@AgNRs) of variable lengths have been synthesized
by a new methodology that shows enhancement in catalytic activity
as a function of nanorod length. Detailed characterization by atomic-scale
resolution spectroscopy, precision scattering measurements, high-resolution
microscopy, and theoretical modeling through the density functional
theory (DFT) quantifies the presence of an enhanced number of multiple
coaxial twin boundaries for longer Hy-Au@AgNRs, which ultimately results
in an increased mechanical strain. By considering greater mechanical
strain within Hy-Au@AgNRs, the density of states (DOS) calculation
shows a prominent shift in electron density toward the Fermi level
to assist in the tremendous catalytic activity of the longest nanorod
(NR) (Hy-Au@AgNR840). Further assembling of these inherently
active Hy-Au@AgNR840s by thiol click chemistry not only
efficiently creates
multiple low-coordinated crystal sites to improve their catalytic
activity but also the resultant uniform two-dimensional (2D) platform
shows better adsorptivity and easy moldability on the electrode surface
for increased shelf life, a uniform porous structure to trap a large
extent of redox systems, enhanced stability in a broad pH and solvent
range to increase the applicability, and long-term stability under
ambient conditions for safe storing, making this material a unique
nonenzymatic scalable universal electrocatalytic platform. The ability
of this material to act as a nonenzymatic universal catalytic platform
has been verified by applying it for highly specific and ultrasensitive
detection of a series of human metabolites, which include different
important vitamins, potent endogenous antioxidants, essential amino
acids for the biosynthesis of proteins, simple monosaccharides, and
essential trace-metal ions. Our study for the first time mechanistically
explores the combined role of anisometric seeding to create an intermetallic
twin boundary along with its size to control the strain-induced catalytic
activity to offer us a universal 2D electrocatalytic sensing platform
by a combined approach of experiment and theory.
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.