As mentioned above, the active coating RuO2: TiO2= 30:70 (molar ratio) was prepared according to the Beer formula, which is considered to have high electrocatalytic activity and stability in the electroresolving chlorine reaction of brine.
Comninellis believes that for RuO2·TiO2, the most stable is when x (RuO2) = 20%, which is the range of solid solution components.
Zhang Zhaoxian studied the formula of x (TiO2)= 80% and x (RuO2)= 20%, and compared it with graphite electrodes, classic RuTiO, and coated electrodes.
a. x(TiO2) : x(RuO2)= 80:20 component TiO2·RuO2 titanium electrode preparation coating formula, RuCl3 1g, Ti (RuO) 45 ml, HCI 1mL, n-butanol 13mL. At the first two times, the hot oxidation at 420℃ for 10min, from the third time, the hot oxidation at 450℃ for 10min, until the coating solution is coated. Finally, it was sintered at 350℃ for 1h. That is, the TiO2-RUO2 layer titanium electrode of x(TiO2) : x(RuO2)= 80:20 component is prepared.
b. Enhanced life test
Enhanced life test conditions: 0.5mol/L H2S04, 2A/cm2, <40℃. < p="">
The life of the titanium electrode of x(TiO2) : x(RuO2)= 80:20 component TiO2·Ro02 is 16.5h, while the life of the classic x(TiO2) : x(RuO2)= 70:30 group TiO2·RuO2 titanium electrode is only 5.3h, and the strengthening life is increased by about 3 times.
c. Chlorine evolution potential test
The electrolyte was saturated salt aqueous solution, that is, 315g of NaCl per 1L, the heteropolar distance was 3mm, the reference electrode was 232 saturated calomel electrode, and the electrode was titanium electrode.
Before chlorine evolution potential test, electrolysis at 400A/m2 for 30min.
The bath voltage and chlorine evolution electricity of graphite electrode, Ti02*RuO2 titanium electrode with a molar ratio of 70:30 component, and TiO2·Ru02 titanium electrode with a molar ratio of 80:20 component, measured at different current densities are listed in Table 3-7.
Table 3-7 chlorine evolution potentials of various electrodes
Based on the data in Table 3-7, the polarization curves of each electrode are drawn, as shown in Figure 3-9.
Figure 3-9 Polarization curves of chlorine evolution at various electrodes
It can be seen from the data in Table 3-7 and the chlorine polarization diagram in Figure 3-9 that the conductivity of the RuTi electrode is better than that of the graphite electrode. When the working current density is 800A/㎡, and 1500A/㎡, the tank voltage is reduced by 0.4 ~ 0.5V. At various current densities, the chlorine evolution potential value of RuTi electrode is lower than that of graphite electrode, which is 200 ~ 300mV lower, and the chlorine evolution potential value of x (TiO2) : x (RuO2) = 80:20 component TiO2·RuO2 coated titanium electrode is lower, indicating the highest chlorine evolution electrocatalytic activity.
d. Oxygen evolution potential test
The H2S04 in the electrolyte is 0.5mol/L, the heteropolar distance is 3mm, the reference electrode is mercurous sulfate electrode and the electrode is titanium electrode.
Before the test, electrolysis was performed at 500A/㎡ for 30min.
The cell voltage and oxygen evolution electricity of x(TiO2) : x(RuO2)= 70:30 component Ti02· RuO2-coated titanium electrode and x(Ti02) : x(RuO2)= 80:20 component TiO2-RuO2-coated titanium electrode measured at different current densities are listed in Table 3-8.
Table 38 Oxygen evolution potential of TiO2-RuO2 electrode
The slot voltage and oxygen evolution potential of the coated titanium electrode are slightly lower than that of the friction electrode
As can be seen from the data in Table 3-8, the group is divided into 70:30 TiO2·RuO2 titanium electrodes with 80:20 molar ratio under various current densities.
Compared with the classical x(TiO2) : x(RuO2)= 70:30 component titanium electrode, the developed x(TiO2) : x(RuO2)= 80:20 component coated titanium electrode has little difference in the tank voltage, chlorine evolution potential and oxygen evolution potential, but the strengthening life is longer and increased by about 3 times.
Titanium-based platinum group metal oxide electrode has been developed in brine electrolysis industry, which has high catalytic activity of chlorine evolution and can be used for more than 15 years.
Electrode coating components :x(TiO2) :x(RuO2)= 60:40, chlorine evolution current efficiency is 92%; x(TiO2) : x(RuO2) : x(IrO2)= 60:20:20, with an electric efficiency of 93%.
