How to Prepare Coated Titanium Anodes through the Thermal Decomposition Method

How to Prepare Coated Titanium Anodes through the Thermal Decomposition Method?

Thermal decomposition methods have been adopted to prepare coated titanium anode, a few micrometers of the oxide layer are deposited on titanium substrate. These oxides are seldom used alone, they are usually doped or mixed with less active oxides of higher chemical stability.

Thermal decomposition preparation of MMO coated titanium anode is achieved thermochemically by dissolving the suitable metal salts in a solvent (alcohol or acidified water). The solution is then applied to the prepared titanium substrate by dip coating or brush painting or spin coating. The solvent is evaporated and the remaining material is decomposed to form the metal oxide on the titanium.

Generally, coated titanium anodes have a corrosion resistant valve metal commercially pure titanium. The substrate is coated with an electrocatalytic layer of a noble metal (Ru, Ir, Pd, etc), a noble metal oxide (RuO2, IrO2, PdO2, etc), a valve metal oxide (TiO2, Nb2O5, Ta2O5, etc), or a mixture of them.

Coated titanium anodes are prepared by pretreating the surface of the substrate by degreasing, chemical etching, or sandblasting to increase the surface area and enhance adhesion of the coating. Pretreated titanium substrate can be painted, dip-coated, or spin-coated.

Precious metal loadings in coatings usually range from 0.1-3 mg cm-2. Electroplating, sputtering and electroless deposition are other deposition techniques that can be employed for coating the electrode. Conductive polymers have also been investigated as substrates for coated titanium anodes.