A Novel Three-Electrode Solid Electrolyte Hydrogen Gas Sensor - Intelligent Computing for Sustainable Energy and Environment - page 42

The dynamic property of hydrogen's oxidation and phosphotungstic acid's
reduction varies on different electrodes, so i 0 H + /H 2 , i 0 HPW , β H , α HPW , E HPW ,
the mixed potential and the discipline that it complies with the hydrogen con-
centration are also different.
After introducing the adjusting electrode based on the two-electrode sensor,
the mixed potential and the discipline that it complies to the hydrogen con-
centration, of the measuring electrode and adjusting electrode who have differ-
ent catalytic dynamics are different. So the potential between the measuring
electrode and the reference electrode and the potential between the adjusting
electrode and the reference electrode will show different trends. The responding
curve of the sensor and the detecting range will extend accordingly.
4 Experiments
The sensor was assembled in a sealed container with a complete gas path. The
standard concentration hydrogen was obtained by adjusting the volume ratio of
the hydrogen and the insert gas. In order to avoid the external electromagnetic
interference to the voltage signal, the sensor was placed in the box to shield the
electromagnetic wave.
4.1 The Results of the Two-Electrode Solid Electrolyte Hydrogen
Sensor in Detecting Hydrogen Concentration
To acquire the relationship between the electromotive force and the hydrogen
concentration, the hydrogen concentrations were adjusted to 0, 0.1%, 0.2%, 0.3%,
0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%. The results were shown in Figure 3. The
results show that the output electromotive force of the sensor is sensitive to the
hydrogen concentration. The sampled data were plotted in Figure 3 and the curve
is similar to be logarithmic shape. However, the slope decrease with the increase
of the hydrogen concentration. Especially for the concentration range higher
than 1%, the two-electrode solid electrolyte hydrogen sensor has relatively lower
resolution, which in turn result in the unrecognized hydrogen concentration.
4.2 The Results of the Three-Electrode Solid Electrolyte Hydrogen
Sensor in Detecting Hydrogen Concentration
For the three-electrode solid electrolyte hydrogen sensor, the hydrogen concen-
tration was adjusted to 0, 0.3%, 0.6%, 1.4%, 2.2%, 2.9%, 3.7%, 4.5%, 5.2%, 6.9%,
8.3%, 9.8%, 11.4%, 12%. The electromotive forces between Pt electrode and W
electrode and between Ni electrode and W electrode were measured simulta-
neously. The relationship between the electromotive force of Pt-W electrodes
and the hydrogen concentration is shown in Figure 4, and the relationship be-
tween electromotive force of Ni-W electrodes and the hydrogen concentration
is shown in Figure 5. The measured results show that the electromotive force