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

Abstract

The nano-structured ternary PtIrRu particles were co-deposited onto the titanium substrates (Pt 64 Ir 33 Ru 3 /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 Pt 64 Ir 33 Ru 3 /Ti electrode towards the oxygen reduction reaction (ORR) and oxidation of formic acid and methanol in 0.5 M H 2 SO 4 was evaluated by voltammetric techniques, chronoamperometric responses and electrochemical impedance spectra (EIS). Results show that Pt 64 Ir 33 Ru 3 /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 Pt 64 Ir 33 Ru 3 /Ti presents significantly higher anodic current densities and lower onset potentials in comparison to Pt. Potential-time transient measurements show that the Pt 64 Ir 33 Ru 3 /Ti exhibits high steady-state current densities for both the formic oxidation and methanol oxidation. The EIS data indicate that the Pt 64 Ir 33 Ru 3 /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 Pt 64 Ir 33 Ru 3 /Ti catalyst. This confirms the high electrocatalytic activity of the Pt 64 Ir 33 Ru 3 /Ti for the formic acid and methanol oxidation.