Enhancement of the catalytic performance for CH3OH oxidation of nanoporous Pt by the addition of Cu and Ce to precursors

Abstract

Melt-spun Al-Pt-Cu-Ce ribbons were chosen to prepare a nanoporous composite formed by thinner Pt ligaments with loaded CeO2. Dealloying the ribbons in 20 wt% NaOH prior to a calcination at 500 °C, allowed us to achieve nanoporous structures consisting of Pt/CuO ligaments. During the first synthetic step, Pt-Cu unlimited solid solution was obtained calcination yielded a microstructure composed by Pt nanoparticles embedded in a CuO matrix, creating highly narrow Pt nanopores. To remove the CuO matrix, a second corrosion treatment (50 wt% NaOH) was carried out, producing a microstructure in which CeO2 nanorods were blended with Pt ligaments. These samples had a large specific area of 116.75 m2·g−1 with 0.301 cm3·g−1 of pore volume. The highest peak current density for CH3OH oxidation (1310 mA·mg−1Pt) was obtained for the dealloyed Al81.5Pt8Cu10Ce0.5 ribbons. The peak current density ratio between the forward (If) and the backward scan (Ib) of the dealloyed Al-Pt-Cu-Ce increased up to 7.4, indicating excellent poison tolerance. The unique composite structure of CeO2 nanorods embedded with Pt ligaments led to a strong interaction between CeO2 and Pt. As a result, the composite exhibited better poison tolerance with enhanced catalytic activity.