Pristine graphene covalent functionalization with aromatic aziridines and their application in the sensing of volatile amines - an ab initio investigation.

Sabrine Baachaoui,Alessandro Fortunelli,Sarah Aldulaijan,Luca Sementa,Fayçal Raouafi,Noureddine Raouafi,Adnene Dhouib,Rafaa Besbes

doi:10.1039/d0ra09964c

Abstract

Food quality is of paramount importance for public health safety. For instance, fish freshness can be assessed by sensing the volatile short chain alkylamines produced by spoiled fish. Functionalized graphene is a good candidate for the design of gas sensors for such compounds and therefore of interest as the basic material in food quality sensor devices. To shed theoretical insight in this direction, in the present work we investigate via first-principles density functional theory (DFT) simulations: (i) graphene functionalization via aziridine appendages and (ii) the adsorption of short chain alkylamines (methylamine MA, dimethylamine DMA, and trimethylamine TMA) on the chemically functionalized graphene sheets. Optimal geometries, adsorption energies, and projected density of states (PDOS) are computed using a DFT method. We show that nitrene reactive intermediates, formed by thermal or photo splitting of arylazides – p-carboxyphenyl azide (1a), p-carboxyperfluorophenyl azide (1b), and p-nitrophenyl azide (1c) – react with graphene to yield functionalized derivatives, with reaction energies >−1.0 eV and barriers of the order of 2.0 eV, and open a ∼0.3 to 0.5 eV band gap which is in principle apt for applications in sensing and electronic devices. The interaction between the amines and functionalized graphene, as demonstrated from the calculations of charge density differences showing regions of charge gain and others of charge depletion between the involved groups, occurs through hydrogen bonding with interaction energies ranging from −0.04 eV to −0.76 eV, and induce charge differences in the system, which in the case of p-carboxyperfluorophenyl azide (1b) are sizeable enough to be experimentally observable in sensing.

Highlights

Pristine graphene, a one atom thick layer of carbon arranged in a honeycomb shape 2D crystal, is extensively investigated from theoretical and experimental point of views to unveil its potential applications.[1,2,3,4,5,6] Its zero-energy gap prevents it from being used as such in electronics.[7]
To shed theoretical insight in this direction, in the present work we investigate via first-principles density functional theory (DFT) simulations: (i) graphene functionalization via aziridine appendages and (ii) the adsorption of short chain alkylamines on the chemically functionalized graphene sheets
We show that pristine graphene can be modi ed with various nitrene intermediates, generated from the decomposition of azides, to yield the corresponding aziridine-modi ed graphenes, representing a novel path to functionalized graphene materials

Summary

Introduction

A one atom thick layer of carbon arranged in a honeycomb shape 2D crystal, is extensively investigated from theoretical and experimental point of views to unveil its potential applications.[1,2,3,4,5,6] Its zero-energy gap prevents it from being used as such in electronics.[7]. The interaction between the amines and functionalized graphene, as demonstrated from the calculations of charge density differences showing regions of charge gain and others of charge depletion between the involved groups, occurs through hydrogen bonding with interaction energies ranging from À0.04 eV to À0.76 eV, and induce charge differences in the system, which in the case of p-carboxyperfluorophenyl azide (1b) are sizeable enough to be experimentally observable in sensing.

Results

Conclusion