Crystal-defect-induced facet-dependent electrocatalytic activity of 3D gold nanoflowers for the selective nanomolar detection of ascorbic acid

Abstract

Understanding and exploring the decisive factors responsible for superlative catalytic efficiency is necessary to formulate active electrode materials for improved electrocatalysis and high-throughput sensing. This research demonstrates the ability of bud-shaped gold nanoflowers (AuNFs), intermediates in the bud-to-blossom gold nanoflower synthesis, to offer remarkable electrocatalytic efficiency in the oxidation of ascorbic acid (AA) at nanomolar concentrations. Multicomponent sensing in a single potential sweep is measured using differential pulse voltammetry while the kinetic parameters are estimated using electrochemical impedance spectroscopy. The outstanding catalytic activity of bud-structured AuNF [iAuNFp(Bud)/iGCp ≅ 100] compared with other bud-to-blossom intermediate nanostructures is explained by studying their structural transitions, charge distributions, crystalline patterns, and intrinsic irregularities/defects. Detailed microscopic analysis shows that density of crystal defects, such as edges, terraces, steps, ledges, kinks, and dislocation, plays a major role in producing the high catalytic efficiency. An associated ab initio simulation provides necessary support for the projected role of different crystal facets as selective catalytic sites. Density functional theory corroborates the appearance of inter- and intra-molecular hydrogen bonding within AA molecules to control the resultant fingerprint peak potentials at variable concentrations. Bud-structured AuNF facilitates AA detection at nanomolar levels in a multicomponent pathological sample.

Wide Range Morphological Transition of Silver Nanoprisms by Selective Interaction with As(III): Tuning–Detuning of Surface Plasmon Offers To Decode the Mechanism

“…Literature is rich with reports for the detection of arsenic either by laboratory-based analytical procedures ,− or by using noble metal nanomaterials, − but the mechanistic revelation of selective detection of arsenic , is not only seldom but also superficial in nature. On the basis of their wealth of optical properties (absorption, emission, and scattering), the noble metal nanoparticles (NPs) find high-throughput applications in different advanced fields, − which include sensing, diagnostics, therapeutics, optoelectronics, catalysis, alternate energy, etc. Surface plasmon resonance (SPR) − bands of noble metal NPs are typically located in the vis–near-infrared region and are strongly dependent on the NP size, shape, composition, crystallinity, interparticle spacing, and local dielectric environment. ,− Out of several noble metal NPs, silver nanoprism (AgNPr) is one of the most promising candidates for multicolor diagnostic labeling purposes because of its easy tunability of the broadband in-plane dipole SPR simply by adjusting the aspect ratios (AR s ) = L / T where L = side length of the prism and T = thickness of the prism and by inducing their two-dimensional (2D) and three-dimensional assemblies .…”

Size‐Dependent Catalytic Behavior of Gold Nanoparticles

“…Such defect structures include twin boundary, grain boundary, edge dislocation, screw dislocation, stepped surface, kink, and island. [23] To sum up, it seems that there are presumably more defects on the surface of the larger AuNP due to their inherent deficiencies generated from the synthetic methods.…”

Au-Seeded Ag-Nanorod Networks for Electrocatalytic Sensing

“…In our previous studies, we have shown that pure gold nanostructures with a {110} facet have a strong affinity toward ascorbic acid. 66 In contrast, gold−silver nanoalloys with a {220} orientation show enormous oxidizing capability for uric acid. 50 Thus, the chemical composition (pure vs alloy) of the nanocatalyst determines the adsorption efficiency and facet selectivity of the substrate and subsequent bond-breaking and bond-forming process during a reaction.…”