Strategy and mechanism for controlling the direction of defect evolution in graphene: preparation of high quality defect healed and hierarchically porous graphene

Abstract

In this paper, a novel approach for controlling the direction of defect evolution in graphene through intercalation of organic small molecules into graphite oxide (GO) combined with a one-pot microwave-assisted reaction is reported. By using ethanol as intercalator, the bulk production of high quality graphene with its defects being satisfactorily healed is achieved. The repair of defects using extraneous carbon atoms and the hybrid state of these carbon atoms are definitely demonstrated using isotopic tracing studies with (13)C-labeled ethanol combined with (13)C solid-state NMR. The defect healed graphene shows excellent crystallinity, extremely low oxygen content (C : O ratio of 23.8) and has the highest sheet conductivity (61 500 S m(-1)) compared to all other reported graphene products derived from GO. By using methanol or benzene as intercalators, hierarchically porous graphene with a self-supported 3-dimensional framework (∼917 m(2) g(-1)) containing both macropores and mesopores (2-5 nm) is obtained. This graphene possesses a distinctive amorphous carbon structure around the edge of the nanopores, which could be conducive to enhancing the lithium storage performance (up to 580 mA h g(-1) after 300 cycles) when tested as an anode of lithium ion batteries, and might have promising applications in the field of electrode materials, catalysis, and separation, and so on. The mechanism involved for the controlled defect evolution is also proposed. The simple, ultrafast and unified strategy developed in this research provides a practical and effective approach to harness structural defects in graphene-based materials, which could also be expanded for designing and preparing other ordered carbon materials with specific structures.

Effect of nanostructure on the supercapacitor performance of activated carbon xerogels obtained from hydrothermally carbonized glucose-graphene oxide hybrids

“…Table 2). As will be further discussed below in the light of the electrochemical characterization results, a potential consequence of the extensive removal of oxygen atoms is that the remaining aromatic domains could incorporate significant amounts of unsaturated, highly reactive edges [31,32], particularly when activation is carried out at a lower temperature that is less carboxylic and ester functionalities). Generally, the C 1s XPS spectrum of a pure graphitic material without heteroatoms presents an asymmetric shape.…”

Heterojunctions Derived by Integrating Arylene-Ethynylene Nanobelts and N-Doped Graphene for Molecular Sensing

“…As shown in Figure 1C, GO exhibited an initial weight-loss below 200 °C due to the desorption of interlamellar water. 43 The main weight loss then occurred within 200−500 °C, which is attributed to the decomposition of the oxygen-containing groups. As a temperature higher than 500 °C, the further weight loss is due to the decomposition of the more stable functional groups.…”

Preparation of a graphene-based composite aerogel and the effects of carbon nanotubes on preserving the porous structure of the aerogel and improving its capacitor performance

“…It is reported that a carbon rich atmosphere might repair the defects of carbon based materials and improve their electrical conductivity. 35,36 The active sample GCA/C was prepared and the electrochemical performances of GCA, GCA/C and GCA/CNT were characterized by CV test to understand the electrochemical behaviour changes of GCA/CNT. It is observed that all the three electrodes exhibit quasi-rectangular curves at low scan rates of 5 mV s À1 (Fig.…”

“…Moreover, the added carbon nanotubes may increase the electrical conductivity and improve the electrochemical performance by forming a unique three dimensional electrical conductive network. In addition to carbon nanotubes, the added carbon source at high temperatures may heal the defects of the pyrolyzed resol carbon and graphene sheets, 35,36 which further enhance the electrochemical performance of GCA/CNT.…”