Highly Efficient Room-Temperature Gas Sensor Based on TiO2 Nanotube-Reduced Graphene-Oxide Hybrid Device

In this letter, a highly efficient room-temperature gas-sensor device based on the hybrid structure of TiO
₂
nanotubes and reduced graphene oxide (RGO) is reported. TiO
₂
NTs were grown by the electrochemical anodization technique followed by the electro-deposition of RGO layer in the form of discrete islands. The synergistic hybridization of the two different sensing elements was found to be superior to the performance of the individual ones. Room temperature (~27°C) gas-sensing performance, with methanol as a test species, was carried out and the fastest response and recovery times, reported so far, were achieved due to high carrier mobility of RGO. On the other hand, appreciably high response magnitude (96.93% at 800 ppm) was obtained due to the increased number of gas-interaction sites and availability of free surface energy provided by titania nanotubes and RGO. A comparative discussion elucidating the role of TiO
₂
NTs-RGO junctions has also been presented co-relating the experimental findings.