Facile preparation of porous palladium nanocubes via a one-pot process induced by 1-hexadecyl-3-methyl imidazolium bromide for methanol electro-oxidation

Abstract

Palladium nanoparticles with a uniform shape and specific surface structure have gained tremendous attention owing to their fascinating catalytic performance. Herein, Pd porous nanocubes (PdPNs) were successfully synthesized through a facile one-pot non-seeded routine using 1-hexadecyl-3-methyl imidazolium bromide (HMIB) as the capping agent. The as-prepared PdPNs had a cubic shape and highly porous feature with an average size of 45.4 nm. The morphology evolution along with time was investigated by transmission electron microscopy and a possible formation mechanism of PdPNs was proposed. The effects of the concentration of HMIB and temperature on the structure and electrocatalytic activity were also investigated. The PdPNs showed superior catalytic activity (j_f = 13.11 mA cm⁻²) in methanol electro-oxidation in an alkaline medium to solid Pd nanocubes (j_f = 7.25 mA cm⁻²) and a commercial Pd/C catalyst (j_f = 0.11 mA cm⁻²). Meanwhile, PdPNs exhibited excellent stability, which was inferred from the current density remaining at 86.3% of the initial value after 1500 cycles.