Structure and chemistry of surface-doped Pt:SnO2 gas sensing materials
Surface-doped Pt:SnO2 was synthesized by impregnation of calcined SnO2 made by an aqueous sol–gel route. The structure of the introduced Pt-dopant and its behaviour during gas exposure were examined by in situ and operando X-ray absorption spectroscopy. The results reveal that Pt forms a nano-sized PtO2 phase, which was not found for bulk and surface doped materials, studied previously. In a comparative investigation of undoped and Pt-doped SnO2 gas sensors the performance and the surface chemistry were investigated, the latter one using operando FT-IR spectroscopy. The results prove the strong influence of the different Pt structures on the surface chemistry of SnO2, providing the basis for an understanding on the varying sensor performance of differently synthesized Pt:SnO2 gas sensing materials.