Preparation and characterization of nanostructured Pd with high electrocatalytic activity

Two kinds of Pd nanoparticle aggregates with different electrocatalytic activity are developed in a facile hydrothermal synthesis method. The average size of Pd nanoparticles synthesized from the mixed solvent containing water and acetone (Pd–M) is ∼9 nm smaller than that of Pd samples synthesized from aqueous systems (Pd–A) with the size of ∼14 nm. Nanoparticles of Pd–M and Pd–A show the crystalline nature based on the XRD and HRTEM results. It is found that Pd–M display a remarkably high electrooxidation activity per unit mass toward formic acid and ethanol, which is 8–12 times as high as that of Pd–A. The electrooxidation activity per unit area of Pd–M is also higher than that of Pd–A. The formation mechanisms of Pd–A and Pd–M as well as the relationship between their microstructures and electrocatalytic activity have been discussed based on the experimental results.

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► Pd nanocrystal aggregates show high electrocatalytic activity toward formic acid and ethanol.
► Pd nanocrystals with controlled size are prepared through hydrothermal process.
► Addition of acetone into the synthesis systems leads to the formation of smaller Pd nanocrystals.
► Smaller Pd nanocrystals show much higher catalytic activity than that of larger Pd nanocrystals.