Synthesis and Electrochemical Study of Three-Dimensional Graphene-Based Nanomaterials for Energy Applications.

Graphene is an attractive soft material for various applications due to its unique and exclusive properties. The processing and preservation of 2D graphene at large scales is challenging due to its inherent propensity for layer restacking. Three-dimensional graphene-based nanomaterials (3D-GNMs) preserve their structures while improving processability along with providing enhanced characteristics, which exhibit some notable advantages over 2D graphene.

Synthesis and Electrochemical Study of Mesoporous Nickel-Cobalt Oxides for Efficient Oxygen Reduction.

Development of a cost-effective and efficient electrocatalyst for the sluggish oxygen reduction reaction (ORR) is a crucial challenge for clean energy technologies. In this study, we have synthesized various Ni and Co oxide (NCO) nanomaterials via a facile coprecipitation, followed by the calcination method. The morphology of the formed NCO nanomaterials was controlled by varying the percentage of the Ni and Co precursors, leading to the formation of a template-free mesoporous spinel phase structure of Ni CoO.

Sensitive Electrochemical Detection of Caffeic Acid in Wine Based on Fluorine-Doped Graphene Oxide.

We report here a novel electrochemical sensor developed using fluorine-doped graphene oxide (F-GO) for the detection of caffeic acid (CA). The synthesized graphene oxide (GO) and F-GO nanomaterials were systematically characterized with a scanning electron microscope (SEM), and the presence of semi-ionic bonds was confirmed in the F-GO using X-ray photoelectron spectroscopy. The electrochemical behaviours of bare glassy carbon electrode (GCE), F-GO/GCE, and GO/GCE toward the oxidation of CA were studied using cyclic voltammetry (CV), and the results obtained from the CV investigation revealed that F-GO/GCE exhibited the highest electrochemically active surface area and electrocatalytic activity in contrast to the other electrodes.

Shape-controlled synthesis of CoO for enhanced electrocatalysis of the oxygen evolution reaction.

A facile two-step synthesis of 1D nanorod, 2D nanosheet, and 3D nanocube-shaped Co3O4 was demonstrated. The formed 1D, 2D, and 3D Co3O4 were systematically probed using a structure sensitive electrochemical oxygen evolution reaction (OER), revealing that the 2D nanosheets exhibited higher catalytic activities in contrast to the 1D and 3D Co3O4, due to their high electrochemically active surface area and rich oxygen deficiencies. This study also showed that there was a tradeoff between the 2D and 3D Co3O4 in terms of OER activity and stability.

From graphite to interconnected reduced graphene oxide: one-pot synthesis and supercapacitor application.

An innovative one-pot approach for the scalable production of novel interconnected reduced graphene oxide (IC-RGO) is demonstrated, and we name it the streamlined Hummers method (SHM). The formed IC-RGO represents a new type of three-dimensional platform, promising for many graphene related energy, environmental and medical applications.

Residual metal impurity aids facile in situ electrochemical surface derivatization of single-walled carbon nanotubes.

Residual metal impurities were exploited as reactants in the functionalization of the surface of single-walled carbon nanotubes (SWCNT) with nickel hexacyanoferrate (NiHCF) by simple electrochemical cycling in ferricyanide solutions. This facile in situ electrochemical modification process provides intimate contact between NiHCF and SWCNTs that improves the stability of the redox property and reactivity of NiHCF. The characteristic redox behavior of NiHCF on SWCNT surfaces can be used as an electrochemical probe to access qualitative and quantitative information on unknown electroactive metal impurities in SWCNTs.

Improved heterogeneous electron transfer kinetics of fluorinated graphene derivatives.

Though graphitic carbons are commercially available for various electrochemical processes, their performance is limited in terms of various electrochemical activities. Recent experiments on layered carbon materials, such as graphene, demonstrated an augmented performance of these systems in all electrochemical activities due to their unique electronic properties, enhanced surface area, structure and chemical stabilities. Moreover, flexibility in controlling electronic, as well as electrochemical activities by heteroatom doping brings further leverage in their practical use.

Facile and one pot synthesis of gold nanoparticles using tetraphenylborate and polyvinylpyrrolidone for selective colorimetric detection of mercury ions in aqueous medium.

In this work, we reported for the first time, a facile and one step synthesis of gold nanoparticles from HAuCl(4), employing tetraphenylborate as the reducing agent. The synthesis is not only facile but also yields "dumb-bell-shaped"particles. This shape appears to arise from a possible emulsion of the products of oxidation/decomposition of tetraphenylborate by HAuCl(4), surrounding the particle.