Effect of the preparation methodology on some physical and electrochemical properties of Ti/Ir_xSn_(1−x)O₂ materials

The aim of this work was to prepare electrodes based on the Ti/Ir_xSn_(1−x)O₂ composition, as well as test their stability toward the chlorine evolution reaction (ClER). To this end, two different preparation routes were investigated: thermal decomposition of polymeric precursors (DPP) and standard decomposition using isopropanol as solvent (SD/ISO). A systematic investigation of the structural, morphological, and electrochemical properties of the anodes with a nominal composition of Ti/Ir_xSn_(1−x)O₂, prepared through the two different methodologies, was carried out. The oxide layer surface morphology, microstructure, and composition were investigated by Energy Dispersive X-ray Spectroscopy (EDS) and Scanning Electron Microscopy (SEM) techniques prior to and after accelerated life tests. EDS analyses following total deactivation of the electrode gave evidence of a relatively large content of Ir in the coating. XRD results showed there was formation of solid solution between IrO₂ and SnO₂, and the degree of miscibility of these solutions is controlled by the preparation method. Thus, the DPP method led to phase separation and large interval of immiscibility between the oxides analyzed. On the other hand, the SD/ISO method led to formation of solid solution for all the investigated compositions. The SD/ISO method produced materials rich in Ir, so the electrode lifetime was much longer if compared with the DPP counterparts.