Measurements in transient regimes after steep humidity changes: a method for investigating the reaction sites in SnO/sub 2/ gas sensors

Most information about the gas-sensing properties of polycrystalline tin dioxide in the usual commercial gas-sensors is furnished only by steady-state conductance measurements. However many aspects of the surface-gas interaction, and thus of the operation of gas sensors are still unclear. Broadening the field of experimental methods for investigating surface phenomena is therefore very necessary.