Effects of different pretreatments on Ti/RuO2-TiO2 anode

Abstract

In this study, H2C2O4, H2SO4, HNO3, and HCl were used to etch the TA2 titanium matrix at the same concentration and temperature, and the effects of different acid etching methods on the properties of the titanium matrix and Ru-Ti electrode were investigated. The surface morphology of the titanium substrate and anode after acid etching was observed by scanning electron microscopy (SEM), while the electrochemical performance of the anode was determined by cyclic voltammetry (CV), linear sweep voltammetry (LSV), and tafel plots. SEM observations showed that H2C2O4 had the best etching effect on the titanium substrate, as the scratches were uniform, and the surface cracks of the prepared anode reached 4–6 μm; Analysis of the CV curves revealed that the Ti/RuO2-TiO2 anode prepared by H2C2O4 etching had the highest surface charge capacity (172 mC) compared to the anodes prepared by other acid etchings, while the LSV curves showed that the Ti/RuO2-TiO2 anode after H2C2O4 etching had the lowest polarization potential (1.232 V). Tafel curve analysis revealed that the corrosion potential of the Ti anode prepared by H2C2O4 etching was 0.203 V, and the self-corrosion current density was −5.11 A cm−2, indicating that the corrosion resistance of the Ti anode prepared by H2C2O4 treatment is the weakest. X-ray photoelectron spectroscopy analysis showed that the electrode surface changed from Ru4+ to Ru3+ after corrosion, with the Ti2p spectra showing similar transition from Ti4+ to Ti3+.