Study On Titanium-based Metal Oxide Anode With Tantalum Interlayer Coating

Ti-based metal oxide anodes with excellent electrocatalytic activity and electrochemical stability have become ideal auxiliary anodes in Chlor-alkali industry, hydrometallurgy, organic synthesis, cathodic protection, electrochemical pollution, industrial plating.For the further increase of the service life and the electrochemical properties of the anode, we have prepared metal oxide anode with tantalum interlayer in the paper and studied the effect of the tantalum interlayer on the metal oxide anode. Morphology, surface composition and crystal structure were characterized by means of SEM, EDX and XRD. The cyclic voltammetry, polarizing curve measurement, electrochemical impedance spectroscopy and accelerated life were tested to evaluate the electrochemical properties and durability of the oxide anode.The process of thermal decomposition of TaCl5 butanol solution in the inert atmosphere(≥99.99% N2) was studied with thermogravimetry (TGA) and differential scanning calorimetry (DSC). The results shows that thermal decomposition process of TaCl5 butanol solution is almost finished at about 300℃with final product containing Ta, O and little residual C1.The preparation process of tantalum interlayer with thermal decomposition and magnetron sputtering method were studied. The results indicate that, the tantalum coating prepared with thermal decomposition presents surface morphology of dried-mud cracks and the coating components include Ta, Ta2O and/or Ta2O5, which is affected by the temperature of thermal decomposition and the coating layers. With magnetron sputtering method, the tantalum coating surface is dense with layer shape. This is affected by tantalum coating sputtering deposited time. The coating is mainly composed of Ta. The compact surface and high crystallinity of the coating were obtained by magnetron sputtering method.The structure and performance of Ti/Ta/IrO2-Ta2O5 anode with different number of tantalum interlayer by thermal decomposition method and the deactivation mechanism of anode after accelerated life test were investigated. It is found that the anode with tantalum interlayer present less cracks on surface. The oxygen evolution potential and the stability are enhanced. With further increaser of the thickness of the tantalum interlayer, the oxygen evolution potential of Ti/Ta/IrO2-Ta2O5 anode is not changed, but the anode stability is reduced. The deactivation of Ti/Ta/IrO2-Ta2O5 anode is mainly caused by IrO2 dissolution.The structure and performance of Ti/Ta/IrO2-Ta2O5 anode with tantalum interlayer by magnetron sputtering method and the deactivation mechanism of anode after accelerated life test were studied. It is found that the electrode surface shows less cracks after adding tantalum interlayer. The redox peak was appeared on anode cyclic voltammetry after increase tantalum interlayer. In Contrast to the Ti/IrO2-Ta2O5 anode, the voltammetric charge Q*, oxygen evolution potential and stability of Ti/Ta/IrO2-Ta2O5 anode were enhanced. The deactivation of the Ti/Ta/IrO2-Ta2O5 anode is also caused by surface IrO2 dissolution, consistant with the Ti/Ta/Ir2-Ta2O5 anode with tantalum interlayer by thermal decomposition method.