Cu-based amorphous alloy electrodes for fuel cells

Abstract

The present work describes the characteristics of Cu–Zr and Cu–Ti amorphous alloys as catalysts for oxidation of methanol and formaldehyde in alkaline solutions. Two Cu-based amorphous alloys, Cu₆₀Zr₄₀ and Cu₆₀Ti₄₀ both prepared by melt spinning were investigated. Two types of electrode were used: as-quenched amorphous alloys and surface-activated amorphous alloys. The surface-activation treatment consisted in the immersion of the ribbons in 1 M HF solution for 30 s. The determination of the oxidation activity of methanol and formaldehyde was carried out by galvanostatic and by steady-state polarization measurements and cyclic voltammetry experiments in 1 M NaOH solutions containing CH₃OH or CH₂O, deoxygenated by nitrogen bubbling for 30 min at 30 °C. The HF-treated amorphous alloys exhibit catalytic activity only for formaldehyde oxidation; Zr-based alloys show higher current densities than pure crystalline copper and Ti-based alloys.