Electrocatalytic Activity of Nanoporous Pt–Ir Materials toward Methanol Oxidation and Oxygen Reduction

Abstract

Nanoporous bimetallic electrocatalysts with different contents of iridium (Ir%: 15, 28, 40, and 50) were prepared using a one-step facile hydrothermal method. Formaldehyde was used as the reduction agent to simultaneously reduce and , resulting in the formation of bimetallic nanoporous structures. Scanning electron microscopy and energy dispersive X-ray spectroscopy were employed to characterize the surface morphology and composition of the as-synthesized samples. A number of electrochemical methods were used to study the electrochemical activity of the different nanoporous electrodes toward methanol oxidation and oxygen reduction. Our electrochemical studies show that the synthesized nanoporous electrodes possess extraordinarily high electroactive surface areas and that the presence of Ir significantly improves the electrocatalytic activity of Pt toward the electrochemical oxidation of methanol and the electrochemical reduction of oxygen. Of the synthesized nanoporous electrodes, the electrode exhibits the highest electrocatalytic activity. The steady-state current density of the nanoporous electrode for methanol oxidation at is 345 times higher than that of a polycrystalline Pt electrode and over four times higher than that of a nanoporous Pt electrode