Anchoring of IrO₂ on One-Dimensional Co₃O₄ Nanorods for Robust Electrocatalytic Water Splitting in an Acidic Environment

Utilization of noble iridium holds vital importance in energy storage devices for rendering durable performance as an anodic material. In continuation of the efforts being devoted for effective consumption of iridium, on employing two step facile hydrothermal synthesis, we present a highly effective approach for its best utilization. Anchoring of tiny IrO2 nanoparticles on the surface of well-aligned one-dimensional substrate (Co3O4), at an expense of atomically just 6–7% of iridium in relative to cobalt, showed superb durability in an acidic environment. A durable 20-fold enhanced mass specific activity was observed for the best mixed composite relative to that of IrO2. Moreover, compared to iridium dioxide’s Tafel slope of 68.2 mV dec–1 and onset potential of 1.48 V, a quite steeper Tafel slope of 51.2 mV dec–1 and an improvement of 30 mV in onset potential were observed. This outstanding performance is believed to be the synergistic effect of metal cations on account of their electronic modulations as revealed from XPS analysis and due to the experimentally verified importance of one-dimensional nano-rod-shaped assembling of substrate particles. The adopted approach in the current study provides the most effective route for cutting down extensive iridium utilization via synergistic coupling with a nonprecious transition metal, which is vital for the current electrochemical conversion technologies.