Highly Selective Mercury Detection at Partially Oxidized Graphene/Poly(3,4-Ethylenedioxythiophene):Poly(Styrenesulfonate) Nanocomposite Film-Modified Electrode

Abstract

Partially oxidized graphene flakes (po-Gr) were obtained from graphite electrode by an electrochemical exfoliation method. As-produced po-Gr flakes were dispersed in water with the assistance of poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS). The po-Gr flakes and the po-Gr/PEDOT:PSS nanocomposite (po-Gr/PEDOT:PSS) were characterized by Raman spectroscopy, Fourier transform-infrared spectroscopy (FT-IR), UV-Vis spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). In addition, we demonstrated the potential use of po-Gr/PEDOT:PSS electrode in electrochemical detection of mercury ions (Hg 2+ ) in water samples. The presence of po-Gr sheets in PEDOT:PSS film greatly enhanced the electrochemical response for Hg 2+ . Cyclic voltammetry measurements showed a well-defined Hg 2+ redox peaks with a cathodic peak at 0.23V, and an anodic peak at 0.42V. Using differential pulse stripping voltammetry, detection of Hg 2+ was achieved in the range of 0.2-14 µM (R 2 = 0.991), with a limit of detection of 0.19 µM for Hg 2+ . The electrode performed satisfactorily for sensitive and selective detection of Hg 2+ in real samples, and the po-Gr/PEDOT:PSS film remains stable on the electrode surface for repeated use.Therefore, our method is potentially suitable for routine Hg 2+ sensing in environmental water samples.

Partially Oxidized Graphene/Metallic Single‐Walled Carbon Nanotubes Film‐Coated Electrode for Nanomolar Detection of Dopamine

“…Graphene and its derivatives, such as graphene oxide (GO) and reduced GO (rGO) have received ample attention in recent years in chemical, biosensing, energy storage/production, and biology applications due to their high electrical conductivity (the sheet resistance is ∼62.4 Ω/sq per layer of graphene) 5, large surface‐to‐volume ratio, biocompatibility, robust mechanical strength, and high flexibility 6. We recently reported an electrochemical exfoliation method to synthesize partially oxidized graphene (po‐Gr) flakes 7. The po‐Gr flakes are soluble in water due to the partial oxidation and defect sites created during electrochemical exfoliation.…”

“…Raman spectrum of graphite sheet showed a very small D band (at ∼1351 cm −1 due to fewer defects on the graphitic structure) and a large G band (at ∼1591 cm −1 ) 7 (Figure 2A, curve i). Exfoliated po‐Gr sheets exhibited a large D band (at ∼1346 cm −1 ), a G band (at ∼1588 cm −1 ) and a 2D band (at ∼2690 cm −1 ), which indicated significant defects on its surface (Figure 2A, curve iii).…”

Recovery of critical metals from dilute leach solutions – Separation of indium from tin and lead

“…For example, indium deposition is about 10 5 times faster from solutions in which the basic ion [In(H2O)5OH] 2+ predominates than it is from acidic solutions in perchloric acid where the indium is present as In(H2O) [38]. In earlier work [39,40] the authors have described the development of electrochemical cells designed to monitor trace levels of metals, to recover metals from dilute solution [41], to separate cobalt and nickel [42], and to simultaneously remove metals and degrade organic contaminants in effluent streams [43][44][45].…”

Azo dye functionalized graphene nanoplatelets for selective detection of bisphenol A and hydrogen peroxide

“…DPV is a very sensitive and commonly used electroanalytical technique to determine trace level of elements 52 . The specificity of our sensor was evaluated in the presence of other organic and inorganic species which are usually present along with BPA.…”

“…The production of this peak could be due to the introduction of graphene nanomaterial that can increase the electroactive surface area of the electrode 52 were injected into the electrolyte under stirring (~300 rpm). The production of this peak could be due to the introduction of graphene nanomaterial that can increase the electroactive surface area of the electrode 52 were injected into the electrolyte under stirring (~300 rpm).…”