Electroless deposition of RuO₂-based nanoparticles for energy conversion applications

This study reports a delicate electroless approach for the deposition of RuO₂·nH₂O nanoparticles on the VO ·mH₂O nanowires and this method can be extended to deposit RuO₂·nH₂O nanoparticles on various material surfaces. Electrochemical characterizations, including linear sweep voltammetry (LSV), electrochemical quartz crystal microbalance (QCM) analysis and rotating ring-disc electrode (RRDE) voltammetry, were carried out to investigate the growth mechanism. The deposition involves the catalytic reduction of dissolved oxygen by the V⁴⁺ species of VO ·mH₂O, which drives the oxidation of RuCl₃ to proceed with the growth of RuO₂·nH₂O. This core/shell VO ·mH₂O/RuO₂·nH₂O shows a better catalytic activity of the oxygen reduction reaction (ORR) than RuO₂·nH₂O, which is ascribed to the pronounced dispersion of RuO₂·nH₂O. Such an electroless approach was applicable to the preparation of a RuO₂-based nanoparticle suspension as well as the deposition of nanocrystalline RuO₂·nH₂O on other functional supports like TiO₂ nanowires. The thus-obtained RuO₂-decorated TiO₂ nanorods exhibit significantly an enhanced photoactivity toward photoelectrochemical water oxidation. The versatility of the current electroless approach may facilitate the widespread deployment of nanocrystalline RuO₂·nH₂O in a variety of energy-related applications.