Room temperature toluene gas sensor based on TiO2 nanoparticles decorated 3D graphene-carbon nanotube nanostructures

By Yotsarayuth Seekaew, A. Wisitsoraat, D. Phokharatkul, C. Wongchoosuk. Sensors and actuators. B, Chemical, 2019

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Abstract This work presents a highly sensitive room-temperature gas sensor based on 3D titanium dioxide/graphene-carbon nanotube (3D TiO2/G-CNT) fabricated by chemical vapor deposition and sparking methods. Characterizations by scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and Transmission electron microscopy confirmed the formation of 3D graphene-carbon nanotube nanostructures decorated with TiO2 nanoparticles. The toluene detection performances of 3D TiO2/G-CNT structures with varying Ti sparking times were investigated in comparison with 3D G-CNT, TiO2-CNT, graphene and CNTs at room temperature. From result, the optimal sparking time of 60 s led to an optimal sensor response of 42%–500 ppm at room temperature. In addition, the optimal 3D TiO2/G-CNT exhibited substantially higher toluene response, sensitivity and selectivity than 3D G-CNT, TiO2-CNT, graphene and CNTs over a low concentration range of 50–500 ppm. The toluene-sensing mechanisms of 3D titanium dioxide/graphene-carbon nanotube nanostructures were proposed based on the formation of Schottky metal-semiconductor junctions between metallic 3D graphene-carbon nanotube structures and n-type semiconducting titanium dioxide nanoparticles due to the adsorption of toluene molecules via low-temperature reducing reactions or direct charge transfer process.

Subfields: Bioengineering, Biomedical Engineering, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/462c924918cd99713ea70004f0bfab1925b69be0