A Size-Controlled Graphene Oxide Materials Obtained by One-Step Electrochemical Exfoliation of Carbon Fiber Cloth for Applications to In Situ Gold Nanoparticle Formation and Electrochemical Sensors—A Preliminary Study

Abstract

A simple, one-step and facile method has been introduced to prepare fluorescent and electrochemically active carbon nanoparticles with single-size distribution and good long-term stability by electrochemical exfoliation of polyacrylonitrile-based carbon fibers in an alkaline solution-phase condition. The preparation condition was systematically optimized by studying the effect of temperature and electrolytes. It has been found that an electrochemical exfoliation reaction carried out at an applied potential of 2 V vs. Ag/AgCl in a phosphate-ion-containing alkaline solution at a temperature of 40 °C is an ideal condition for the preparation of 14 ± 4 nm-sized carbon nanoparticles. Unlike the literature protocols, there are no filtration and membrane dialysis-based off-line sample pretreatments adopted in this work. The as-prepared carbon nanoparticles were characterized by fluorescence, Raman spectrum, transmission electron microscope, and X-ray photoelectron spectroscopic characterization methods. It was found that the carbon–oxygen functional group rich in graphene–oxide quantum dots (GOQDs) such as carbon nanoparticles were formed in this work. A preliminary study relating to simultaneous electrochemical oxidation and the sensing of uric acid and ascorbic acid with well-resolved peaks was demonstrated as a model system to extend the new carbon material for electroanalytical applications. Furthermore, in situ synthesis of 2 nm-sized gold nanoparticles stabilized by GOQDs was presented. The carbon nanoparticles prepared by the direct method in this work have shown good stability over 6 months when stored at room temperature. The electrochemical exfoliation reaction has been found to be highly reproducible and suitable for bulk synthesis of luminescence-effective carbon nanoparticles to facilitate fundamental studies and practical applications.

Electrochemical synthesis of fluorescence-enhanced carbon dots with multicolor emission via surface nitrogen and sulfur modulation for information encryption applications

“…As a reference, Table S1 (ESI †) lists the QY of different CDs synthesized using electrochemical methods. 25,[28][29][30][31] The emission of N,S-BCDs, N,S-GCDs N,S-RCDs could be tuned and the peak intensities are significantly increased by nitrogen-sulfur surface modification, as compared to that of OCDs. As shown in Fig.…”

Recent trends in nanostructured carbon-based electrochemical sensors for the detection and remediation of persistent toxic substances in real-time analysis

“…Without using any precise off-line cleaning and segregation techniques, Chang et al [138] revealed a straightforward one-phase electrochemical method to produce homogeneous GOQDs) exfoliated via a carbon cloth crafted of polyacrylonitrile (PAN) fiber in an alkaline media comprising sulfate ions (figures 14(A)-(C)) [138]. Without the use of any polymeric or gelators or surfactant stabilizers in the media, the 'as-produced GOQDs water dispersal technique' demonstrated better long-term durability.…”

Novel Concepts for Graphene-Based Nanomaterials Synthesis for Phenol Removal from Palm Oil Mill Effluent (POME)

“…The cloth was immersed in an electrochemical cell with sodium hydroxide electrolytes as the working electrode, silver or silver chloride as the reference electrode, and a platinum wire as the auxiliary electrode. The resultant GO nanomaterials were formed as quantum dots with a size of ~2 nm [ 66 ]. This method leads to the formation of highly pure GO nanomaterials with high yields and comparatively large graphene sheets compared to liquid-phase exfoliation.…”