This paper explores the reduction of water dispersed graphene oxide (GO) by sunlight. The electronic and structural properties of the sunlight reduced GO are compared with that of GO reduced by conventional methods.

Pradeep Thalappil

Department Of Chemistry

Soujit Sen Gupta

Mohandoss M

Gupta S.S

Nelleri A

Pradeep T

Maliyekkal S.M.

Anith Nelleri

Cost effectiveness

Defects

Electronic properties

Graphene

Conventional methods

DEGREE OF REDUCTION

Dispersibilities

ELECTROCHEMICAL ENERGY STORAGE DEVICES

ENVIRONMENTALLY FRIENDLY ALTERNATIVES

Possible mechanisms

Reduction process

Structural defect

reduction

Fulltext

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

RSC Advances

This paper demonstrates the appropriateness of the Spectroscopic Ellipsometry (SE), a non destructive optical characterization technique in analyzing the optical properties of a few layers of reduced graphene oxide (RGO) in NIR-UV-Vis range of spectrum. The paper discusses the study of the optical properties of RGO sample prepared by exposing GO to natural sunlight. The Drude-Lorentz model is used to extract the optical constants of RGO from the ellipsometric measurement. This paper investigates how the optical parameters change due to the variations in the degree of reduction along with the presence of defects on RGO sheets. The result reveals that the refractive index (n) and the extinction coefficient (k) increase, with the increase in the level of reduction. The effect of the variations in structural defects and the presence of functional groups on the absorption coefficient are studied. The paper also discusses the sensitivity of ellipsometry in analyzing the variations in the dielectric constant due to presence of the residual oxygen moieties. Such detailed optical characterization of RGO samples has great potential application in deciding the best suitable reduction technique for developing specific optical device. © 2018 Elsevier B.V.

Optical Materials

Optical properties of sunlight reduced graphene oxide using spectroscopic ellipsometry

Unprecedented adsorption of chlorpyrifos (CP), endosulfan (ES), and malathion (ML) onto graphene oxide (GO) and reduced graphene oxide (RGO) from water is reported. The observed adsorption capacities of CP, ES, and ML are as high as ~1200, 1100, and 800 mg g(-1) , respectively. Adsorption is found to be insensitive to pH or background ions. The adsorbent is reusable and can be applied in the field with suitable modifications. A first-principles pseudopotential-based density functional analysis of graphene-water-pesticide interactions showed that the adsorption is mediated through water, while direct interactions between graphene and the pesticides is rather weak or unlikely.

Small

Graphene: A reusable substrate for unprecedented adsorption of pesticides

This paper describes a versatile, and simple synthetic route for the preparation of a range of reduced graphene oxide (RGO)-metal/metal oxide composites and their application in water purification. The inherent reduction ability of RGO has been utilized to produce the composite structure from the respective precursor ions. Various spectroscopic and microscopic techniques were employed to characterize the as-synthesized composites. The data reveal that the RGO-composites are formed through a redox-like reaction between RGO and the metal precursor. RGO is progressively oxidized primarily to graphene oxide (GO) and the formed metal nanoparticles are anchored onto the carbon sheets. Metal ion scavenging applications of RGO-MnO2 and RGO-Ag were demonstrated by taking Hg(II) as the model pollutant. RGO and the composites give a high distribution coefficient (Kd), greater than 10Lg-1 for Hg(II) uptake. The Kd values for the composites are found to be about an order of magnitude higher compared to parent RGO and GO for this application. A methodology was developed to immobilize RGO-composites on river sand (RS) using chitosan as the binder. The as-supported composites are found to be efficient adsorbent candidates for field application. © 2010 Elsevier B.V.

Journal of Hazardous Materials

Reduced graphene oxide-metal/metal oxide composites: Facile synthesis and application in water purification

Diamond and Related Materials

Effects of reduction methods on the structure and thermal conductivity of free-standing reduced graphene oxide films

Vacuum

X-ray photoelectron spectroscopy of reduced graphene oxide prepared by a novel green method

Physica E: Low-dimensional Systems and Nanostructures

Hydrothermal method for the production of reduced graphene oxide

Solar mediated reduction of graphene oxide

Journal	Data powered by TypesetRSC Advances
Publisher	Data powered by TypesetRoyal Society of Chemistry
ISSN	20462069
Open Access	No