Significant enhancement in the hydrogen-sensing performance of polypyrrole/titanium oxide (PPy/TiO2) hybrid sensors by a chemical oxidation polymerization approach

Abstract

Novel polypyrrole/titanium oxide (PPy/TiO2) hybrid sensors were fabricated by an in situ chemical oxidation polymerization approach. The structural and morphological information of the sensing films were analyzed through X-ray diffraction, atomic force microscopy and Raman analysis. The huge surface area (121 m2/g) and highly porous nature (15–20 nm) of the PPy/TiO2 composite film was identified via a N2 adsorption–desorption analysis. The resistance-type gas sensors were fabricated and monitored CO2 and H2 gases with different ppm levels. The results revealed that PPy/TiO2 composite film sensors showed a tremendous gas-sensing response (66%), and fast response (19 s) and recovery times (27 s) with long-term stability. The sensing characteristics were further monitored using different voltaic gases like NH3, NO2, LPG and SO2, etc., and the sensors exhibited good selectivity and a higher response towards H2 gas than other gas spices. The proposed sensors are a promising material for application in the hydrogen gas sensor industries. The sensing mechanism is also elaborated and discussed.