The preparation and gas sensitivity study of polythiophene/SnO2 composites

Nanocomposites of SnO2 and polythiophene (PTP) were synthesized by the in situ chemical oxidative polymerization method. These nanocomposites were characterized by FTIR, transmission electron microscope (TEM), X-ray diffraction (XRD) and thermogravimetric and differential thermal analysis (TG–DTA) techniques, which proved the polymerization of thiophene monomer and the strong interaction between polythiophene and SnO2. The composites were used for gas sensing to methanol (MeOH), ethanol (EtOH), acetone, and NOx at different working temperature. It was found that PTP/SnO2 materials with different PTP mass percent (1%, 5%, 10%, 20% and 30%) could detect NOx with very higher selectivity and sensitivity at much lower working temperature than the reported SnO2. The PTP/SnO2 nanocomposites responded to NOx at concentration as low as 10 ppm. PTP/SnO2 composite containing 5 mass% PTP showed the highest sensitivity at room temperature. The sensing mechanism of PTP/SnO2 nanocomposites to NOx was presumed to be the effects of p–n heterojunction between PTP and SnO2.