Report

Shape regulation of high-index facet nanoparticles by dealloying

See allHide authors and affiliations

Science  13 Sep 2019:
Vol. 365, Issue 6458, pp. 1159-1163
DOI: 10.1126/science.aax5843

You are currently viewing the abstract.

View Full Text

Log in to view the full text

Log in through your institution

Log in through your institution

Stabilizing rougher nanoparticles

For many reactions catalyzed by metal nanoparticles, the more exposed metal atoms on high-index faces can be more active than metal atoms on smooth, low-index faces. Surface ligands can be used to stabilize high-index surfaces, but they can also be hard to remove. Huang et al. report the solid-state synthesis of metal nanoparticles such as platinum and chromium that can form tetrahexahedral nanoparticles with high-index faces. Metals such as bismuth and lead were alloyed with the transition metals at high temperatures and then evaporatively dealloyed during a quench to room temperature.

Science, this issue p. 1159

Abstract

Tetrahexahedral particles (~10 to ~500 nanometers) composed of platinum (Pt), palladium, rhodium, nickel, and cobalt, as well as a library of bimetallic compositions, were synthesized on silicon wafers and on catalytic supports by a ligand-free, solid-state reaction that used trace elements [antimony (Sb), bismuth (Bi), lead, or tellurium] to stabilize high-index facets. Both simulation and experiment confirmed that this method stabilized the {210} planes. A study of the PtSb system showed that the tetrahexahedron shape resulted from the evaporative removal of Sb from the initial alloy—a shape-regulating process fundamentally different from solution-phase, ligand-dependent processes. The current density at a fixed potential for the electro-oxidation of formic acid with a commercial Pt/carbon catalyst increased by a factor of 20 after transformation with Bi into tetrahexahedral particles.

View Full Text

Stay Connected to Science