The nature of surface behavior of tin oxide doped sensors: X-ray photoelectron spectroscopy studies before and after exposure to liquid petroleum gas Original Research Article

X-ray photoelectron spectroscopy studies have been carried out to investigate the possible chemical species involved in the gas–solid interaction and enhancing mechanism of the Pd-doped SnO2 sensor element. In the case of SnO2 and SnO2/Al2Si2O7, when the samples are exposed to liquid petroleum gas (LPG), the SnO2 is reduced to metallic Sn indicating adsorption–desorption (chemical mechanism). Whereas in the case of SnO2/Pd and SnO2/Al2Si2O7/Pd systems in addition to chemical mechanism, there is an additional contribution from the Pd, in which PdO2 and PdO are reduced to PdO and Pd, respectively, attributed to electronic mechanism. It has been observed that the electronic mechanism is more predominant than the chemical one.