Tuning Cu₂O Shell on Gold Nanocube Core Employing Amine-Functionalized Silane for Electrocatalytic Nitrite Detection

Abstract

A facile synthetic method for depositing copper­(I) oxide (Cu2O) shell on Au nanocube (AuNC) core with different core–shell ratios (1:1, 1:5, 1:10, and 1:20) is reported. An innovative approach of tuning the Cu2O nanoshell for utilizing the catalytic activity of the AuNC@Cu2O core–shell nanostructures is investigated. N-[3-(trimethoxysilyl)­propyl]­diethylenetriamine (TPDT) silane played a dual role in the formation and stabilization of the Cu2O shell on the AuNC core. The optimal concentration of TPDT silane required for forming a stable Cu2O shell is studied systematically and deployed for fabricating AuNC@Cu2O core–shell nanostructures with various core-to-shell ratios. UV–vis absorption spectroscopy, high-resolution electron transmission microscopy analyses, scanning electron microscopy coupled with line scan energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and inductively coupled plasma mass spectrometry techniques were used to characterize the prepared AuNC@Cu2O core–shell nanostructures. High-angle annular dark-field scanning transmission electron microscopy–energy-dispersive X-ray spectroscopy mapping images–line scan image and scanning electron microscopy coupled with line scan energy-dispersive X-ray spectroscopy were recorded to understand the core–shell nature of AuNC@Cu2O nanostructures. The electrocatalytic activity of AuNC@Cu2O core–shell nanostructures with different Cu2O shell thicknesses toward nitrite detection was investigated using the cyclic voltammetry technique. The TPDT-stabilized AuNC@Cu2O nanostructure with the core–shell ratio of 1:10 showed the best electrocatalytic activity, and the estimated detection limit of nitrite concentration was found to be as low as 14.7 nM.

Amine-Functionalized Silane-Assisted Preparation of AgNP-Deposited α-Ni(OH)2 Composite Materials and Their Application in Hg2+ Ion Sensing

“…ATR-FTIR spectra were recorded to further confirm the existence of Ni­(OH) 2 /TPDT silane (Figure S4). The IR absorption band observed at 463 cm –1 corresponds to the Ni–OH stretching mode, and the other band observed at 1064 cm –1 corresponds to the stretching vibration of Si–O–Si bond in TPDT silane …”

“…The IR absorption band observed at 463 cm –1 corresponds to the Ni–OH stretching mode, 6 and the other band observed at 1064 cm –1 corresponds to the stretching vibration of Si–O–Si bond in TPDT silane. 32 …”

Synthetic Approaches to Colloidal Nanocrystal Heterostructures Based on Metal and Metal-Oxide Materials

“…Owing to these advantageous features, these CNHSs can serve not only as catalytic nanoreactors or capacitors, but also as sacrificial templates for the preparation of hollow oxide capsules upon etching of the metal core [ 27 ]. Valuable prototypes of Au@Cu 2 O [ 65 , 66 , 67 ] and Au@CeO 2 [ 68 ] CNHSs were also delivered by aqueous routes. Shape-tailored Au@Cu 2 O CNHSs were synthesized by a room-temperature alkaline CuCl 2 reduction with NH 2 OH on shaped Au CNC seeds in the presence of sodium dodecylsulphate as a surfactant [ 65 ].…”

“…Regardless of the appreciable differences between the lattice parameters of Au and Cu 2 O, the as-derived core@shell CNHSs incorporated epitaxial interfaces: the shell could be tailored either with a profile conformal to that of the Au core or shaped independently over a broad size range [ 65 ] ( Figure 1 c–e). More recently, the formation of near-spherical Au@Cu 2 O CNHs with a mesoporous Cu 2 O shell was achieved by reduction of copper acetylacetonate over Au seeds in the presence of ascorbic acid as reductant and of n -oleyl-1,3-propanediamine as capping agent at 100 °C [ 66 ] A conceptually similar approach was utilized to produce electrocatalytically active spherical Au@Cu 2 O CNHSs provided with thin Cu 2 O shell [ 67 ]. In the synthesis of Au@CeO 2 CNHs [ 68 ], a CeO 2 shell with an adjustable degree of continuity could be deposited over Au seeds, starting from Ce(NO 3 ) 2 in an aqueous alkaline medium: the precursor was induced to hydrolyze and oxidize by dissolved O 2 in the presence of citrate anions as a complexing agent for cerium ions and stabilizer for the evolving oxide [ 68 ].…”

Integration of Ultrathin Bubble Walls and Electrochemistry: Innovation in Microsensing for Forensic Nitrite Detection and Microscale Metallic Film Deposition

“…This quick cleansing process allows for direct detection of nitrite ions in the surfactant solution using an ultramicrosensor, eliminating the need for complex instruments or sample preparation steps. Currently, a diverse array of techniques has been used for the measurement and screening of NO 2 – ions within gunshot residue, encompassing methodologies such as spectrophotometry, colorimetry, fluorescence, and electrochemical analysis. − Of these, electrochemical analysis is frequently employed owing to its inherent simplicity and rapid execution. ,− In contrast, techniques involving mass spectrometry and chromatographic methods often necessitate comprehensive preparation of the sample, costly and technologically advanced equipment, and skilled analysts. Now, the purposed method provides an alternative that is more accessible, expedient, and economically efficient, characteristics that render it advantageous for applications within forensic investigations.…”