Proposal for Deposition Mechanism of Electrochemical-Constructed IrO2-Ta2O5|Ti Electrodes
Authors: Herrada Rosa Alhelí , Bustos Erika 
Published: February 2020

Dimensionally Stable Anodes (DSA) were invented by Henri Beer in 1965 under the brand name DSA. These electrodes are characterized by their shape and structural integrity and included a catalytic coating with corrosion resistance properties [1-2]. These materials are very appealing for many applications because of their high chemical and electrochemical stability, low cost and exceptional ability to catalyze electrochemical reactions [3]. Also, DSA electrodes are able to produce hydroxyl radicals (·OH) at the interface level, which may have a large number of applications [4-5]. DSA electrodes usually employ titanium as a support material and can be coated with oxides of transition metals. For this investigation, the electrodes were coated with IrO2 and Ta2O5 due to their excellent performance.

There are many investigations focused on the applications of these types of electrodes, but it is necessary to increase the information related to titanium pretreatment and the mechanism of iridium and tantalum deposition in order to thoroughly understand the structure of such electrodes [6-9]. Studies focused on coating quality enhancement are important in order to increase their performance, catalytic properties and stability against corrosion.

A crucial factor for DSA synthesis is the titanium pretreatment, which aims to increase the electrode area and clean it in order to facilitate the deposition of transition metals. For this investigation, titanium electrodes were sandblasted and etched with oxalic acid [1-2]. Also, there are factors related to the deposition, such as the concentration of salts in the precursor solution and its subsequent thermal treatment.

The main goal of this research is to modify titanium electrodes with IrO2 and Ta2O5 by electrochemical deposition and study the changes in the electrode surface during the different stages of pretreatment and modification, in order understand the deposition mechanism and to improve their catalytic activity in the generation of hydroxyl radicals at the interface level [3].

The modified surfaces were characterized by Cyclic Voltammetry (CV), Diffraction X-Ray (DRX), perfilometry, Scanning Emission Microscopy (SEM) and Energy Dispersive X-Ray spectroscopy (EDX). Additionally, the production of ·OH was monitored by UV-Vis spectrophotometry.

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Figure 1