As mentioned earlier,the RuO2:TiO2=30:70(molar ratio)active coating prepared according to the Beer formula is considered to have high electrocatalytic activity and stability in the salt water electrolysis chlorination reaction.

Comninelli believes that for RuO2·TiO2,the most stable state occurs when x(RuO2)=20%,which is within the range of solid solution components.

Zhang Zhaoxian studied the formula of x(TiO2)=80%and x(RuO2)=20%,and compared it with graphite electrode,classical RuTiO,and coated electrode.

a.Preparation of coating formula for TiO2·RuO2 titanium electrode with a composition of x(TiO2):x(RuO2)=80:20,RuCl3 1g，Ti（RuO)4 5mL，HCI 1mL，13mL of n-butanol.Start with two cycles of thermal oxidation at 420℃for 10 minutes.From the third cycle,continue with thermal oxidation at 450℃for 10 minutes until the coating solution is fully applied.Finally,sintering was carried out at 350℃for 1 hour to obtain a TiO2.RuO2 layered titanium electrode with a composition of x(TiO2):x(RuO2)=80:20.

b.Strengthen life test

Enhanced life test conditions:0.5mol/L H2S04,2A/cm2,<;40℃.

The lifespan of the TiO2·Ro02 titanium electrode with a composition of x(TiO2):x(RuO2)=80:20 developed is 16.5 hours,while the lifespan of the classic TiO2·RuO2 titanium electrode with a composition of x(TiO2):x(RuO2)=70:30 is only 5.3 hours,indicating a threefold increase in enhanced lifespan.

c.Chlorine potential test

The electrolyte is a saturated saline solution,which contains 315g of NaCl per 1L,with a distance of 3mm between electrodes.The reference electrode is a 232 type saturated calomel electrode,and the counter electrode is a titanium electrode.

Before conducting the chlorine potential test,electrolyze at 400A/m2 for 30 minutes.

The cell voltage and chlorine evolution potential of graphite electrodes and TiO2·Ru02 titanium electrodes with a molar ratio of 70:30 and a molar ratio of 80:20,measured at different current densities,are listed in Table 3-7.

Table 3-7 Chlorine evolution potential values of various electrodes

Draw the polarization curves of various electrodes based on the data in Table 3-7,as shown in Figure 3-9.

Figure 3-9 Polarization curves of chlorine evolution on various electrodes

From the data in Table 3-7 and the polarization curve of chlorine evolution in Figure 3-9,it can be seen that the conductivity of RuTi electrode is better than that of graphite electrode.When the working current density is 800A/㎡and 1500A/㎡,the slot voltage decreases by 0.4-0.5V.At various current densities,the chlorine evolution potential of RuTi electrode is lower than that of graphite electrode,which is 200-300mV lower.However,the chlorine evolution potential of TiO2·RuO2 coated titanium electrode with x(TiO2):x(RuO2)=80:20 component is lower,indicating that its chlorine evolution electrocatalytic activity is the highest.

d.Oxygen evolution potential test

H2S04 0.5mol/L in the electrolyte,with a distance of 3mm between electrodes.The reference electrode is a mercuric sulfate electrode,and the counter electrode is a titanium electrode.

Before testing,electrolyze at 500A/㎡for 30 minutes.

The cell voltage and oxygen evolution potential of TiO2:RuO2=70:30 and TiO2·RuO2 coated titanium electrodes with different current densities are listed in Table 3-8.

Table 38 Oxygen evolution potential values of TiO2-RuO2 electrode

The slot voltage and oxygen evolution potential of TiO·RuO coated titanium electrodes are slightly lower than those of friction

From the data in Table 3-8,it can be seen that under various current densities,TiO2·RuO2 titanium electrodes with a 70:30 composition and an 80:20 molar ratio are used.

Compared with the classic x(TiO2):x(RuO2)=70:30 composition titanium electrode,the developed x(TiO2):x(RuO2)=80:20 composition coated titanium electrode has little difference in slot voltage,chlorine evolution potential,and oxygen evolution potential,but the enhanced lifespan is longer,increasing by about 3 times.

The saltwater electrolysis industry has developed titanium based platinum group metal oxide electrodes,which have high chlorine evolution catalytic activity and can be used for more than 15 years.

Electrode coating composition:x(TiO2):x(RuO2)=60:40,chlorine evolution current efficiency is 92%;x(TiO2)：x(RuO2)：x(IrO2)=60：20：20，The fluoride electrolysis efficiency is 93%.