H2S sensing characteristics of Pt-doped α-Fe2O3 thick film sensors

α-Fe2O3 nanoparticles doped with different amounts of Pt were synthesized by chemical coprecipitation and characterized by X-ray diffraction (XRD), transmission electron micrograph (TEM) and X-ray photoelectron spectrometer (XPS). The gas sensing properties of the thick film sensors prepared by Pt-doped α-Fe2O3 nanoparticles were investigated and compared with those of undoped α-Fe2O3 sensors. Obtained results indicated that the Pt-doped α-Fe2O3 sensors presented much higher response, better selectivity and rather low optimum operating temperature to H2S than the undoped α-Fe2O3 sensors. The sensor of 2 wt% Pt/α-Fe2O3 still showed excellent response towards very low concentration H2S (10 ppm). The sensing mechanism of the Pt/α-Fe2O3 sensor to H2S was also discussed.