Synthesis of mesoporous platinum-palladium alloy films by electrochemical plating in aqueous surfactant solutions.

Mesoporous platinum-palladium alloy films with different compositional ratios have been successfully synthesized by electrochemical plating in aqueous surfactant solutions. Scanning electron micrographs and transmission electron micrographs reveal that all of the platinum-palladium alloy films possess uniform mesopores with a narrow size distribution (around 7 nm). The alloy compositions in the pore walls can be controlled by changing the compositional ratios in the precursor solutions, as confirmed by inductively coupled plasma mass spectroscopy analysis and X-ray photoelectron spectroscopy measurements. Due to large surface areas, the prepared mesoporous platinum-palladium films show distinctly enhanced electrocatalytic activity for methanol oxidation reactions, compared with the commercially available platinum black catalyst. Furthermore, compared with mesoporous platinum film, the alloying of platinum with palladium has a critical effect on the enhanced electrocatalytic activity. In particular, a mesoporous Pt(82)-Pd(18) film exhibits highly enhanced electrocatalytic activity.