| Summary: | 碩士 === 國立交通大學 === 物理研究所 === 87 === A new H+-sensing Electrode based on sputtered Ta2O5 and IrO2 thin film. The mechanism is that only H+ can pass through Ta2O5 film. To insulate IrO2 film from intruding by other ions, IrO2 film was covered with Ta2O5 film. And the Fermi level of IrO2 film can be varied from the interaction of H+ in the electrolyte. By Nernst's equation, we can see that the potential of IrO2 film can be varied with pH value of the electrolyte.
And then, we made a potentiometric CO2 sensor based on two Ta2O5-IrO2 electrodes. Both Ta2O5-IrO2 electrodes were connected and covered by water contained, bicarbonate doped poly( vinyl alcohol ). One of the electrodes was shielded with an epoxy layer. When the device was exposed to gaseous mixed of CO2, the potential difference between these two electrodes indicated the containment of CO2 in the measurand. This CO2 sensor was a rapid response device. The response to CO2 concentration was linear and reversible.
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