Mixed Metal Oxide TiO ₂ @RuO ₂ Nanostructure over Titanium Substrates as Self-Supporting Electrodes for Oxygen Evolution Reaction

The development of low-cost, efficient, and stable electrodes for electrochemical water splitting remains a serious challenge. Herein, a specific alkaline treatment is used to grow a porous network structure over the surface of the titanium substrates. Afterward, Ru3+ ions are incorporated into the constructed porous network using the SILAR method and an ion exchange process. Loaded Ru3+ ions are subsequently converted into RuO2 using a thermal treatment. During this treatment, there is simultaneous formation of TiO2 and RuO2 which combine to form a TiO2@RuO2 mixed metal oxide nanostructure over the surface of titanium substrates. Resulting self-supporting electrodes (Ti/TiO2@RuO2-x) were characterized using advanced characterization techniques such as XRD, XPS, SEM, EDX, FE-SEM and HR-TEM, and used as counter and working electrodes for OER in an alkaline medium. Electrochemical studies reveal that with low Ru contents of 0.79 ± 0.02 and 2.27 ± 0.09 (at. %) for counter and working respectively, the electron transfer properties, OH– adsorption capacity, and hence, OER activity of the proposed working electrode are significantly enhanced. Moreover, the long-term stability and postcharacterization studies demonstrate the high potential of TiO2 to strongly bind RuO2 at the substrate surface and prevent their dissolution during electrochemical reactions.