Burning Graphene Layer-by-Layer

Abstract

Graphene, in single layer or multi-layer forms, holds great promise for future electronics and high-temperature applications. Resistance to oxidation, an important property for high-temperature applications, has not yet been extensively investigated. Controlled thinning of multi-layer graphene (MLG), e.g., by plasma or laser processing is another challenge, since the existing methods produce non-uniform thinning or introduce undesirable defects in the basal plane. We report here that heating to extremely high temperatures (exceeding 2000 K) and controllable layer-by-layer burning (thinning) can be achieved by low-power laser processing of suspended high-quality MLG in air in “cold-wall” reactor configuration. In contrast, localized laser heating of supported samples results in non-uniform graphene burning at much higher rates. Fully atomistic molecular dynamics simulations were also performed to reveal details of oxidation mechanisms leading to uniform layer-by-layer graphene gasification. The extraordinary resistance of MLG to oxidation paves the way to novel high-temperature applications as continuum light source or scaffolding material.

Enhanced adsorption of methylene blue on chemically modified graphene nanoplatelets thanks to favorable interactions

“…Two main families of graphene commercially available can be mentioned: GO having 2-5 layers and a defected structure due to the numerous functional groups it bears (Dreyer et al 2014) and graphene flakes or graphene nanoplatelets of often more than 10 layers with a good structural quality (Ermakov et al 2015;Wei et al 2009;Stankovich et al 2006;Ghosh et al 2010). With the aim of using a well-controlled graphenic material, we have chosen to work with high quality graphene nanoplatelets (GNPs).…”

Controlled Air‐Etching Synthesis of Porous‐Carbon Nanotube Aerogels with Ultrafast Charging at 1000 A g−1

“…The process of pore creation in PCNs was supposed as follows: 1) HNO 3 treatment provides full anion doping throughout the entire PPy nanotube; 2) parts of the C and N atoms were consumed and escaped as gases during the heat process in Ar, leading to the formation of micropore sites; 3) when temperature arose to 1000 °C, low‐concentration air flow (oxygen was supposed to be the main reactant) was introduced to further consume the C and N atoms around the micropore sites and produce uniform micro‐ and mesopores in the PCN walls. This controlled low‐concentration air etching during the annealing process and the HNO 3 treatment are two critical conditions for creating uniform micropores throughout the PCN walls both in axial direction and radial direction evenly, whereas directly etching graphitic materials by a large amount of O 2 usually produces mesopores, even macropores with irregular distribution, rather than uniform micropores . From a microscopic view, the pore formation process is initiated by the reaction between the N and C atoms with both the anion dopants and air, which would release NO x and CO x gases to leave sub‐nanometer pores .…”

“…[20][21][22][23] From a microscopic view, the pore formation process is initiated by the reaction between the N and C atoms with both the anion dopants and air, which would release NO x and CO x gases to leave sub-nanometer pores. [19][20][21]24] And, the pores will become bigger gradually and evenly (coalescence of micropores into mesopores) under continued air attacking, resulting in a hierarchical porous structure ( Figure 1b).…”

“…This controlled low‐concentration air etching during the annealing process and the HNO 3 treatment are two critical conditions for creating uniform micropores throughout the PCN walls both in axial direction and radial direction evenly, whereas directly etching graphitic materials by a large amount of O 2 usually produces mesopores, even macropores with irregular distribution, rather than uniform micropores . From a microscopic view, the pore formation process is initiated by the reaction between the N and C atoms with both the anion dopants and air, which would release NO x and CO x gases to leave sub‐nanometer pores . And, the pores will become bigger gradually and evenly (coalescence of micropores into mesopores) under continued air attacking, resulting in a hierarchical porous structure (Figure b).…”

Investigation of Graphene Oxide in Diesel Soot

“…In internal combustion engines (ICE), combustion of the fuel, diesel takes place at high temperature producing carbon nanoparticles. The high-temperature combustion may lead to the formation of graphene sheets containing carbon nanotubes and graphene oxide [10]. Lesser the efficiency of ICE greater is the possibility of formation of particulate matter in addition to carbon dioxide and water.…”