Interactions between free radicals and a graphene fragment: Physical versus chemical bonding, charge transfer, and deformation

Abstract

The adsorption of six free radicals (FRs) respectively on a graphene fragment was studied using a density functional tight-binding method with the inclusion of an empirical dispersion term in total energy. The results indicate that the different interaction paths between the FRs and the graphene lead to different forms of physical (PA) or chemical adsorptions (CA). The CA appears only in the condition where some of the nonhydrogen atoms are closer to the graphene, with the deformation occurring in the latter. The charge transfer increases with the increase in adsorption energy in every FR-graphene system. Although the deformation in the graphene is negligible in all PA cases, the FR is closer to the graphene and the graphene deformation is clearer in all CA cases, with all atomic displacements being larger than 0.1 Å. Our findings are useful not only for FR scavenging but also for studying the interaction between general molecules and material surfaces.

The synergistic mechanism of thermally reduced graphene oxide and antioxidant in improving the thermo-oxidative stability of polypropylene

“…Moreover, it is noteworthy that the barrier property of semi-crystalline polymer is not only influenced by nanoplaletes, but also depends on its crystallinity and crystalline structure [38]. 16 graphitic forms should hold the same attractive capability to be an efficient free radical scavenger, which is beneficial for the reduction of the peroxy radical concentration in PP matrix. Herein, the DPPH assay which is widely used to quantify the scavenging capacity of antioxidant towards hydroxyl, alkyl and peroxyl radicals [25], was applied to evaluate the radical scavenging activity of TrGO and AO.…”

“…The interactions between graphene and free radicals, such as ethyl and hydroxyl [16], alkyl and phenalenyl radicals [17], have been investigated by 3 theoretical calculation using a developed density functional tight-binding (DFTB-D) method. Those studies suggested that both physical and chemical adsorption can occur when free radicals approach to the graphene surface.…”

Graphene Oxide-Silica Composite Fillers into the Experimental Dental Adhesives for Potential Therapy

“…Actually, when the adhesive was exposed under the LED light curing unit, amine radicals were formed in the experimental adhesive and could be enriched around GO sheets through physical or chemical adsorptions. [23] Therefore, GO could enhance the degree of conversion by absorption of the radicals and decreasing their mobility. Figure 4 The excitation-dependent PL behavior of GO nanosheets.…”

Organic Chemistry of Graphene: The Diels–Alder Reaction

“…This effect was used to explain the conflicting experimental and theoretical results. Motivated by the differences that were observed in the Diels-Alder chemistry of graphene by Sarkar et al [26] and Bian et al [27] and by the tremendous contribution that theoretical calculations have made to the field of nanotechnology, [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43] we decided to continue our investigation into the reactivity of graphene by using dispersion-corrected density functional theory to investigate the diene and dienophile character of graphene. We expect that our work will shed light on this fascinating topic.…”