Research on gas diffusion mechanisms of limiting current oxygen sensor at low gas pressure

In this article the gas diffusion mechanisms of the limiting current oxygen sensors was studied. For a limiting current oxygen sensor which the pore diameter d is about 30μm, the limiting current Il was quite linear with ln (1-X02) rather than X02 at 1 atm gas pressure, it showed the normal mechanism was more dominant than the Knudsen one. However at the low gas pressure, the limiting current Il was changed with the variation of total gas pressure P. This reveals the gas diffusion mechanisms is neither simply belonged to the normal diffusion nor Knudsen diffusion at low gas pressure. It may be belonged to a mixed diffusion.