The electrochemical reaction of titanium and the working principle of titanium anode
Titanium was discovered in 1791, and the first pure titanium was made in 1910, and it took more than a hundred years in the middle. The reason is that titanium is very active at high temperature, and it is easy to combine with oxygen, nitrogen, carbon and other elements, and very harsh conditions are required to extract pure titanium. In industry, the method of decomposing ilmenite with sulfuric acid is commonly used to prepare titanium dioxide, and then titanium dioxide is prepared from titanium dioxide. The ground ilmenite (concentrate) is treated with concentrated sulfuric acid, and the following chemical reaction occurs: FeTiO3+3H2SO4 = Ti(SO4)2+FeSO4+3H2O FeTiO3+2H2SO4 = TiOSO4+FeSO4+2H2O FeO+H2SO4 = FeSO4+H2O Fe2O3 +3H2SO4 = Fe2(SO4)3+3H2O In order to remove the impurity Fe2(SO4)3, iron filings are added, Fe3+ is reduced to Fe2+, and then the solution is cooled to below 273K, so that FeSO4 7H2O (green alum) is crystallized as a by-product.
Ti(SO4)2 and TiOSO4 hydrolyze white metatitanic acid precipitation, the reaction is: Ti(SO4)2+H2O = TiOSO4+H2SO4 TiOSO4+2H2O = H2TiO3+H2SO4 calcining metatitanic acid to obtain titanium dioxide: H2TiO3 = TiO2+H2O The industrial titanium metal is reduced by metallothermic reduction method to reduce titanium tetrachloride. The TiO2 (or natural rutile) and carbon powder are mixed and heated to 1000-1100K, and the chlorination treatment is carried out, and the generated TiCl4 and steam are condensed. TiO2+2C+2Cl2=TiCl4+2CO Reduction of TiCl4 with molten magnesium in argon at 1070K can obtain porous titanium sponge: TiCl4+2Mg=2MgC12+Ti This sponge titanium is crushed, smelted in a vacuum arc furnace, and finally made into various titanium materials.
In electrochemical reactions, the electrode surface area is accompanied by a heterogeneous catalysis reaction with the movement of charges, which is similar to chemical catalysis. In a certain electrolyte, under the same overpotential, the electrode reaction rate and reaction type change due to the difference of the electrode matrix material, which is collectively referred to as electrocatalysis in electrochemistry. In electrocatalytic reactions, as electrocatalysts, different electrode materials can change the electrochemical reaction rate by orders of magnitude. Therefore, selecting appropriate electrode materials is an effective way to improve the efficiency of electrochemical catalytic reactions. Electrochemical methods have a good effect on the treatment of refractory organic matter, and it can convert non-biochemically degradable organic matter into biochemically degradable organic matter. The electrochemical conversion reaction rate of organic matter is generally slow, so it is often improved by increasing the overpotential of the electrode, increasing the surface area of the electrode, selecting excellent electrode materials, and improving the electrode structure.
In electrochemical reactions, multi-component electrodes are also an important research aspect. The preparation of Ti/SnO2·Sb203"MnO2/Pb02·MnO2 anode can be used as an example of multi-component electrode design. The main reason for the failure of titanium anode is that the new ecological oxygen generated by the oxygen evolution reaction diffuses to the surface of the electrode, thereby forming a A non-conductive TiO2 film is formed. In order to activate the anode, a layer of PbO2·MnO2 active layer is added on the surface of the electrode; in order to reduce the diffusion of new ecological oxygen to the titanium surface, a layer of SnOz·Sb203 is added between the titanium electrode substrate and the active layer. ·MnO2 intermediate layer. The anode has high electrocatalytic activity and electrochemical stability in the treatment of phenol-containing sewage.
Titanium anode is a key component in the water electrolysis machine. The quality of the metal electrode directly affects the quality of the whole water machine. How to choose electrodes should be reasonably selected according to the different working properties. In the field of water treatment, metal electrodes must have the following basic requirements:
1. Has good electrical conductivity.
2. Strong corrosion resistance.
3. Good mechanical strength and processing performance.
4. Long working life.
5. Have good electrocatalytic performance, etc.
