Preparation of Graphite Nanoflakes and Supported Noble Metal/Alloy Nanoparticles by Paired Electrolysis with Graphite Electrodes

Abstract

We report a paired electrolysis method to prepare graphite nanoflakes (GNFs) and their supported noble metal/alloy nanoparticles (NM NPs/GNFs), by applying an alternating voltage (AV) on two graphite rod electrodes in a NaOH solution without/with noble-metal ions. The synthesis of GNFs might be related to the anodic exfoliation of graphite surface via OH − intercalation, accompanying the dispersion effect of hydrogen/oxygen gases evolution. The preparation of NM NPs/GNFs should be resulted from repeated coupling processes, namely the cathodic deposition of NM NPs and the electrochemical exfoliation-dispersion of NM NPs-decorated graphite layer. The as-prepared products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-disperse X-ray spectra (EDX), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic absorption spectroscopy (AAS) and inductively coupled plasma (ICP). The GNFs and NM NPs/GNFs exhibited high electrocatalytic activities toward the redox of 4-nitrophenol and oxidation of formic acid, respectively.

One-step electrochemical synthesis of preferentially oriented (111) Pd nanocrystals supported on graphene nanoplatelets for formic acid electrooxidation

“…There is no other element can be detected by both EDS and XPS analysis suggesting the high purity of Pd/GNP and PdB. The C 1s signal of Pd/GNP originates from the support of GNP, which is comparable to those obtained on graphene and graphite nanoflakes synthesized also by electrochemical exfoliation [29,42]. The deconvoluted XPS spectra of the C 1s peak of Pd/GNP (Fig.…”

Voltammetric Determination of 4-Nitrophenol at Graphite Nanoflakes Modified Glassy Carbon Electrode

“…Preparation of GNFs and GNFs/GCE.-The preparation of GNFs was carried out under continuous stirring by applying alternating voltage (AV, ∼7 V, 50 Hz) with a regulator transformer (Changjiang G.S electronic group Co., Shanghai, China). 32 Two 3-mm-diameter graphite rods were used and immersed about 5 cm in 5 M (M = mol dm −3 ) NaOH solution. Then, the products were collected by centrifugation with 10000 r/min for 15 min, and rinsed by 0.5 M HCl until neutral and Millipore water (thrice), and then by ethanol (twice).…”

“…30,31 In our previous study, we z E-mail: hjhw9513@163.com have developed a simple approach to prepare the GNFs, by applying an alternating voltage on two graphite rods (paired electrolysis) in a blank solution of NaOH. 32 The GNFs modified GCE exhibited obvious electrochemical response toward the reduction/oxidation of 4-NP. Presently, this modified electrode is used to determine 4-NP with cyclic voltammetry.…”

Nitrogen-Doped Graphene via In-situ Alternating Voltage Electrochemical Exfoliation for Supercapacitor Application

“…atom ratio in this sample is 0.09. Further, a dominant peak at 284.6 eV is shown in the high-resolution XPS spectrum of C 1s (Figure 4B), which is assigned to graphitic C=C species, and the other two weak peaks at 285.5 eV and 286.4 eV correspond to sp 3 carbons (C-OH/C-NH 2 ) and oxygen carbons (C-O-C/C=O), respectively (Wang et al, 2014). The O 1s spectrum presents two peaks at 532.1 and 533.7 eV in Figure 4C, which are related to O=C and O-C, respectively (Hou et al, 2015;Bulusheva et al, 2017).…”

“…The electrochemical processes of the as-prepared Gh and N-Gh materials via alternating voltage electrochemical exfoliation have been displayed in Scheme 1. On the basis of previous reports (Wang et al, 2014;Jing et al, 2015), the surface of graphite electrodes were alternately oxidized and reduced during the electrochemical process of alternating voltage. Meanwhile, some cations and anions in the electrolyte solution can intercalate the layers of graphite to accelerate stripping speed.…”