Macrocycle-Functionalized RGO for Gas Sensors for BTX Detection Using a Double Transduction Mode

Elisa Ruiz,Thiaka Gueye,Alain Pauly,Claire Masson,Christelle Varenne,Jérôme Brunet,Amadou L Ndiaye

doi:10.3390/chemosensors9120346

Abstract

To fabricate mass and resistive sensors based on reduced graphene oxide (RGO), we investigated the functionalization of RGO by tetra tert-butyl phthalocyanine (PcH2tBu), which possesses a macroring and tert-butyl peripheral groups. Herein, we present the gas sensor responses of the functionalized RGO toward benzene, toluene, and xylene (BTX) vapors. The RGO was obtained by the reduction of graphene oxide (GO) using citrate as a reducing agent, while the functionalization was achieved non-covalently by simply using ultrasonic and heating treatment. The sensor devices based on both QCM (quartz crystal microbalance) and resistive transducers were used simultaneously to understand the reactivity. Both the GO and the RGO showed less sensitivity to BTX vapors, while the RGO/PcH2tBu presented enhanced sensor responses. These results show that the p-network plays a very important role in targeting BTX vapors. The resistive response analysis allowed us to state that the RGO is a p-type semiconductor and that the interaction is governed by charge transfer, while the QCM response profiles allowed use to determine the differences between the BTX vapors. Among BTX, benzene shows the weakest sensitivity and a reactivity in the higher concentration range (>600 ppm). The toluene and xylene showed linear responses in the range of 100–600 ppm.

Highlights

In the last decade, an unprecedented amount of research on graphene derivatives has been carried out owing to its unique nature and properties [1,2]
Ing to exposure sequences in the 250–500 ppm range (B). These results show that the functionalization of reduced graphene oxide (RGO), as confirmed in the characterizaThese results that the functionalization of RGO, as confirmed in theofcharactertion details above,show by phthalocyanine moieties is efficient for targeting the detection ization details above, by phthalocyanine moieties is efficient for targeting the say detection of Taking into account the fact that graphene oxide bears oxygenated groups, we can that
This study shows, for the first time, a combination of graphene-based materials associated with phthalocyanine for BTX detection using both QCM and resistive transducers simultaneously

Summary

Introduction

An unprecedented amount of research on graphene derivatives has been carried out owing to its unique nature and properties [1,2]. Graphene oxide (GO), which is obtained through the oxidation of graphene, is mainly used for practical applications This is because many technical resources—such as solution processing, surface modification, functionalization, etc.—extrapolated from carbon nanotubes’ surface chemistry are available for the use of graphene oxide (GO) as an allotrope of carbon. These possibilities open unlimited possibilities relating to liquid-phase chemical processing. Another advantage of the solution phase is that it provides reactants that can be incorporated in graphene surfaces to allow for their successful functionalization.

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