Synthesis and electrochemistry study for La doped RuO2-TiO2/Ti coatings

La-doped RuO2-TiO2/Ti coating (TRL) and RuO2-TiO2/Ti coating (TR) were prepared by the sol-gel method and thermal treatment. The products were characterized by X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). The electrochemical properties were investigated by cyclic voltammetry and polarization measurements in O-2 and Cl-2 evolution in H2SO4 and NaCl solution. The XRD analysis showed that in both TRL and TR, the particles of the synthesized coatings were of low crystallinity, and that they were mainly formed of two phases, rutile TiO2 and RuO2. SEM confirmed that the surface of TRL and TR coatings had a cracked mud appearance consisting of blocks separated by cracks. The morphology of the TRL coating shows irregular crack blocks, which increased the specific area greatly and provides more active sites. Polarization measurements indicate that the onset potential of chlorine evolution reaction for TRL coating was 1.08 V-SCE, which is lower than the value of 1.12 V-SCE registered for the TR coating The onset potentials for oxygen evolution for the two coatings were similar. Cyclic voltammetry shows an improvement of the electrochemical capacity for the La-doped coatings.