Hydrothermal synthesis of titanium-supported PtIrRu/Ti electrode and its electrocatalytic activity

The nano-structured ternary PtIrRu particles were co-deposited onto the titanium substrates (Pt64Ir33Ru3/Ti) using a simple hydrothermal method consisting of a one step process. The particle sizes of the deposits, as estimated from the scanning electron microscopy (SEM), were around 170–230 nm. The electrochemical catalytic activity of the titanium-supported Pt64Ir33Ru3/Ti electrode towards the oxygen reduction reaction (ORR) and oxidation of formic acid and methanol in 0.5 M H2SO4 was evaluated by voltammetric techniques, chronoamperometric responses and electrochemical impedance spectra (EIS). Results show that Pt64Ir33Ru3/Ti electrode presents higher steady-state current density and more positive onset potential for the ORR than Pt. For the oxidation of formic acid and methanol, the Pt64Ir33Ru3/Ti presents significantly higher anodic current densities and lower onset potentials in comparison to Pt. Potential-time transient measurements show that the Pt64Ir33Ru3/Ti exhibits high steady-state current densities for both the formic oxidation and methanol oxidation. The EIS data indicate that the Pt64Ir33Ru3/Ti presents very low electrochemical impedance values, showing that both the formic acid oxidation and methanol oxidation exhibit low charge transfer resistances and therefore, present high reaction rates on the Pt64Ir33Ru3/Ti catalyst. This confirms the high electrocatalytic activity of the Pt64Ir33Ru3/Ti for the formic acid and methanol oxidation.