Au Nanoparticles Decorated Graphene-Based Hybrid Nanocomposite for As(III) Electroanalytical Detection

Abstract

Electrochemical sensors integrating hybrid nanostructured platforms are a promising alternative to conventional detection techniques for addressing highly relevant challenges of heavy metal determination in the environment. Hybrid nanocomposites based on graphene derivatives and inorganic nanoparticles (NPs) are ideal candidates as active materials for detecting heavy metals, as they merge the relevant physico-chemical properties of both the components, finally leading to a rapid and sensitive current response. In this work, a hybrid nanocomposite formed of reduced graphene oxide (RGO) sheets, surface functionalized by π-π interactions with 1-pyrene carboxylic acid (PCA), and decorated in situ by Au NPs, was synthesized by using a colloidal route. The hybrid nanocomposite was characterized by cyclic voltammetry and electrochemical impedance spectroscopy with respect to the corresponding single components, both bare and deposited as a layer-by-layer junction onto the electrode. The results demonstrated the high electrochemical activity of the hybrid nanocomposite with respect to the single components, highlighting the crucial role of the nanostructured surface morphology of the electrode and the PCA coupling agent at the NPs-RGO interphase in enhancing the nanocomposite electroactivity. Finally, the Au NP-decorated PCA-RGO sheets were tested by anodic stripping voltammetry of As(III) ion—a particularly relevant analyte among heavy metal ions—in order to assess the sensing ability of the nanocomposite material with respect to its single components. The nanocomposite has been found to present a sensitivity higher than that characterizing the bare components, with LODs complying with the directives established by the U.S. EPA and in line with those reported for state-of-the-art electrochemical sensors based on other Au-graphene nanocomposites.

Electrochemical Sensors Based on Au Nanoparticles Decorated Pyrene-Reduced Graphene Oxide for Hydrazine, 4-Nitrophenol and Hg2+ Detection in Water

“…Finally, the AuNPs/PCA-rGO/SPCEs show a remarkable increase in the current intensity with respect to the PCA-rGO/SPCEs ( Figure 1 C), attesting to a higher electrochemical reactivity, reasonably due to the two-fold increase in the electroactive surface area (A ele ) ( Figure 1 E) estimated by the Randles–Sevcik equation (Equation (1)) [ 18 , 19 , 20 ].…”

“…Au NPs-rGO electron coupling phenomena occurring through PCA molecules and increasing the electrode conductivity, and ii. the presence of the Au NPs catalyzing the [Fe(CN) 6 ] 3₋/4₋ red/ox processes at the electrode surface [ 18 , 19 , 20 , 41 ].…”

“…On the other hand, the use of Au NPs in electrochemical (bio)sensors is advantageous for their capability of binding biomolecules, high rate of heterogeneous electron transfer kinetics, and excellent surface redox electrocatalytic activity [ 17 ]. The combination of the graphene derivatives with Au NPs in hybrid nanocomposites empowers interphase electron coupling, yields materials with a very large electrochemically active surface area, and enhanced heterogeneous electron transfer kinetics, resulting in a rapid and sensitive current response [ 18 , 19 , 20 ]. Therefore, nanostructured platforms formed by these hybrid nanocomposites have been applied for the electroanalytical determination of a variety of analytes, including N 2 H 4 , 4-NP, and Hg 2+ [ 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 ].…”

“…Disposable screen-printed carbon electrodes (SPCEs), modified by hybrid nanocomposites formed by reduced graphene oxide (rGO), functionalized with 1-pyrene carboxylic acid (PCA) and decorated by a dense layer of Au NPs (AuNPs/PCA-rGO/SPCEs), which have been recently demonstrated well-performing for the detection of a variety of analytes including cancer biomarker in human blood serum [ 18 ], vitamin C in food products [ 19 ] and As(III) in water [ 20 ], have been here investigated for the electrocatalytic detection of N 2 H 4 and 4-NP, and after modification with Hg 2+ ions imprinted polycurcumin (polyCM) films, for the electroanalytical quantification of Hg 2+ by differential pulse voltammetry.…”

2D materials: increscent quantum flatland with immense potential for applications

“…Hui et al developed a titanium carbide (Ti 3 C 2 Tx) and multiwalled-carbon-nanotubes (MWNTs) nanocomposites based sensor to detect Zn(II) and Cu(II) ions [ 30 ]. Pifferi et al fabricated a sensor based on rGO sheets, functionalized surface with 1-pyrene carboxylic acid, and loaded in situ by gold nanoparticles to determine As(III) ion [ 130 ]. A traditional electrochemical sensor has a single response signal, and this has limited the reproducibility due to a variety of parameters such as different properties of the base electrode (i.e., area, morphology), the density of probe loading, and complex detection environments.…”