Facet-Inspired Core–Shell Gold Nanoislands on Metal Oxide Octadecahedral Heterostructures: High Sensing Performance toward Sulfide in Biotic Fluids

Abstract

The development of structurally modified metal oxide heteroarchitectures with higher energy facets exposed has been of extensive research interests because of their unique construction and synergy effect of multifunctioning characteristics. In this study, we reported for the first time the development of a distinct type of gold nanoislands (AuNIs) on metal oxides (i.e., Cu 2 O−CuO) octadecahedral (ODH) heterostructures through the galvanic exchange reaction, where Cu 2 O not only acts as a stabilizer but also functions as a reductant. The electrocatalytic performance of the resultant core−shell Cu 2 O− CuO@AuNI ODH-based electrochemical sensing platform has been evaluated in ultrasensitive detection of sulfide as early disease diagnostics and bacterial marker. Owing to the synergistic collaboration of enhanced surface active sites, exposed {110} crystallographic facets, mixed valances of copper that encourage redox reactions at electrode material/analyte interface, and the polarization effect provide by AuNIs decorated onto the Cu 2 O surface, Cu 2 O−CuO@AuNI ODH-modified electrode has demonstrated striking electrochemical sensing performance toward sulfide oxidation in terms of broad linear range, real detection limit down to 1 nM (S/N = 3), and incredible durability and reproducibility. In virtue of marvelous efficiency, the proposed electrochemical sensor based on Cu 2 O−CuO@AuNI ODH has been employed in in situ sensitive detection of a ubiquitous amount of sulfide engendered by sulfate-reducing bacteria and real-time tracking of sulfide efflux from live cells as early diagnostic strategies.

A voltammetric sensor based on mixed proton-electron conducting composite including metal-organic framework JUK-2 for determination of citalopram

“…Based on Randles-Ševčík equation (Eq. 4), the electrochemical active surface area of each tested electrode was calculated [ 30 , 31 ]: where I p is the peak current, A el the electrochemical active surface area of electrode, and v the scan rate ( v = 0.05 V s −1 ), D = 7.2 × 10 −6 cm 2 s −1 [ 29 ].…”

In Situ Electrochemical Mn(III)/Mn(IV) Generation of Mn(II)O Electrocatalysts for High-Performance Oxygen Reduction

“…The electrochemical active surface areas of the electrode were calculated according to the Randles–Sevcik equation (Eq. ( 3 )) [ 22 , 23 ]: where I p refers to the cathodic peak current, n is the total number of electrons transferred ( n = 4), A is the effective surface area of the electrode, D is the diffusion coefficient for KOH = 1.9 × 10 −5 cm S −1 , C * is the concentration of KOH, and v is the scan rate.…”

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“…Moreover, electrochemical biosensors have attracted immense attention of the researchers because of their capabilities to offer sophisticated ways to interface at molecular level, DNA recognition and signal transduction elements and are economical requiring low volume and power for DNA detection [ 93 , 94 ]. The electrochemical biosensing podium to detect different viruses including SARS-CoV-2 has been described in Figure 4 A [ 95 ].…”