Graphene production by cracking.

In recent years, graphene has found its use in numerous industrial applications due to its unique properties. While its impermeable and conductive nature can replace currently used anticorrosive toxic pigments in coating systems, due to its large strength to weight ratio, graphene can be an important component as a next-generation additive for automotive, aerospace and construction applications. The current bottlenecks in using graphene and graphene oxide and other two-dimensional materials are the availability of cost-effective, high-quality materials and their effective incorporation (functionalization and dispersion) into the product matrices. On overcoming these factors, graphene may attract significant demands in terms of volume consumption. Graphene can be produced on industrial scales and through cost-effective top-down routes such as chemical, electrochemical and/or high-pressure mechanical exfoliation. Graphene, depending on end applications, can be chemically tuned and modified via functionalization so that easy incorporation into product matrices is possible. This paper discusses different production methods and their impact on the quality of graphene produced in terms of energy input. Graphene with an average thickness below five layers was produced by both methods with varied defects. However, a higher yield of graphene with a lower number of layers was produced via the high-pressure exfoliation route. This article is part of a discussion meeting issue 'A cracking approach to inventing new tough materials: fracture stranger than friction'.

Liquid phase high shear exfoliated graphene nanoplatelets as counter electrode material for dye-sensitized solar cells.

Graphene nanoplatelets (GNPs) are prepared from natural graphite by a simple and low-cost liquid phase high shear exfoliation method. The as-prepared GNPs are used as a counter electrode (CE) material for dye-sensitized solar cells (DSSCs). To confirm the Exfoliated GNPs, structural and morphological studies are carried out using X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and selected area electron diffraction (SAED) studies. The electrochemical behaviour of GNPs as a counter electrode material is evaluated and compared with standard Platinum (Pt) electrode using cyclic-voltammetry (CV) and electrochemical impedance spectroscopy (EIS). These studies indicated that electrocatalytic activity towards I-/I3- redox mediator exhibited by the GNPs based electrode is comparable to standard Pt counter electrodes. DSSCs are fabricated using the counter electrodes made of GNPs and the photo-conversion efficiency is found to be 6.23% under standard test conditions, which is comparable to Pt based DSSCs proving them as potential alternative materials for counter electrodes.

Graphene based anticorrosive coatings for Cr(VI) replacement.

Corrosion has been a perennial issue of concern for the steel industry. Chromate conversion coatings are well known pre-treatment coatings for steel but due to environmental concerns and legislations, their use has been restricted. The industrial community, pegged by these legislations, has been long demanding an economically viable and eco-friendly pre-treatment coating alternative, without having to compromise on the durability and corrosion performance of the overall coating system. The present study focuses on evaluation of graphene as an anticorrosive alternative to Cr(VI) based coatings. Graphene, produced by a high shear liquid exfoliation route, upon functionalisation, provides a conductive and nearly impermeable barrier coating. On electrochemical and coating performance evaluation of this coating system, a dramatic improvement in corrosion resistance is observed. The study confirms the environment friendly corrosion protection of steel using functionalised graphene coating.