Direct Electrodeposition of Tetrahexahedral Pd Nanocrystals with High-Index Facets and High Catalytic Activity for Ethanol Electrooxidation

Abstract

Tetrahexahedral Pd nanocrystals (THH Pd NCs) with {730} high-index facets were directly produced on a glassy carbon substrate in a dilute PdCl(2) solution by a newly developed programmed electrodeposition method. The THH Pd NCs, thanks to their high density of surface atomic steps, exhibit 4-6 times higher catalytic activity than commercial Pd black catalyst toward ethanol electrooxidation in alkaline solutions. This straightforward method provides a promising route to facile preparation of high-index-faceted metal nanocatalysts with high catalytic activity.

Activity Enhancement of Tetrahexahedral Pd Nanocrystals by Bi Decoration towards Ethanol Electrooxidation in Alkaline Media

“…as we reported previously [26]. The tetrahexahedral shape with 24 facets is seen as being based upon a cube with a pyramid atop each of the six faces [23,26].…”

“…THH Pd nanocrystals (NCs) were prepared based on Sun's method reported previously [26], except a longer square-wave potential treatment time of 40 min (instead of 30 min) was used here [26]. As shown in Fig.1, THH Pd NCs were electrodeposited on the glassy carbon (GC)…”

“…Furthermore, catalytic performance may depend strongly on the size and shape of metal nanocrystals, and thus a unique and accurate control of these parameters is necessary to maximize nanocatalysts' values [24,25]. Sun and co-workers recently developed a novel electrochemical method for the preparation of shape-controllable tetrahexahedral (THH) Pd NCs bounded mainly by (730) facets, which is periodically composed of two (210) steps and one (310) facet [26]. It was demonstrated that the THH Pd NCs exhibit 4-6 times higher catalytic activity than commercial Pd black catalyst for ethanol oxidation reaction, which may be attributed to the high density of low coordination atoms located at the steps, kinks and edges of high-index facets.…”

Recent Development of Pd-Based Electrocatalysts for Proton Exchange Membrane Fuel Cells

“…Other than the common ball-like particles, the particles with multifacets attracted much attention since their unique crystallographic and morphologic structures, which greatly improved the activity and stability when used as fuel cell catalysts. With a square-wave potential method Tian et al [13] electrodeposited tetrahexahedral Pd nanocrystals with {730} high-index facets. With similar technique, Zhou et al [14] prepared the Pd NCs not limited to the tetrahexahedral crystals.…”

“…Porous Pd nanoflowers were prepared by a liquid phase approach [17]. The above Pd particles all show improved mass activity or specific activity in fuel cell reactions, for example the tetrahexahedral Pd shows 4-6 times enhancement of specific activity and 1.5-3 times enhancement of mass activity in ethanol oxidation compared with commercial Pd particles on carbon [13].…”