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The Effects of ZrO 2 on the Electrocatalysis to Yield Active Chlorine Species on Sb 2 O 5 -Doped Ti/RuO 2 Anodes

2016; Institute of Physics; Volume: 163; Issue: 9 Linguagem: Inglês

10.1149/2.0891609jes

1945-7111

Ricardo E. Palma‐Goyes, Jorge Vázquez-Arenas, C. Ostos, Ricardo A. Torres-Palma, Ignacio González,

Advanced battery technologies research

Dimensionally Stable Anodes (Sb2O5-doped Ti/RuO2-ZrO2) are synthesized at four different Zr/Ru molar ratios using the Pechini method to account for the effects of ZrO2 content on the active chlorine formation. X-ray diffraction for ternary catalysts reveal co-deposited phases consisting of a tetragonal crystalline structure (P42/mnm) for RuO2, and two phases corresponding to monoclinic (P2/m) and tetragonal (P42/mnm) crystalline structures for ZrO2. SEM micrographs show that ZrO2 alters grain growth and film morphology as its content is increased. Electrochemical tests performed in 1 mol L−1 H2SO4 and 0.1 mol L−1 NaCl demonstrate that the kinetic rate to perform the oxygen evolution reaction (OER) decreases with the simultaneous augment of ZrO2 and Sb2O5 compositions in the ternary anode, while in the ZrO2 absence, Sb2O5 catalyzes the OER (Ti/SbRu) compared to the Ti/Ru and ternary electrodes. Although the chlorine evolution reaction (CER) preferentially occurs by the suppression of OER in chloride media, the CER rate mainly increases due to the rise of the ZrO2 content. This finding is corroborated with an iodometric method using UV-Vis spectroscopy, which shows that the electro-generation capacity to form active chlorine species is significantly enhanced when ZrO2 is added, compared to Ti/RuO2 and Sb2O5 doped Ti/RuO2 materials. Accelerated life tests conducted with all catalysts indicate that all ternary anodes present failure times considerably longer than Ti/Ru, Ti/SbRu and Ti/RuZr electrodes, suggesting a stability enhancement due to the combined presence of Sb and Zr species.