Three‐Dimensional Branched and Faceted Gold–Ruthenium Nanoparticles: Using Nanostructure to Improve Stability in Oxygen Evolution Electrocatalysis

Abstract

Achieving stability with highly active Ru nanoparticles for electrocatalysis is a major challenge for the oxygen evolution reaction. As improved stability of Ru catalysts has been shown for bulk surfaces with low‐index facets, there is an opportunity to incorporate these stable facets into Ru nanoparticles. Now, a new solution synthesis is presented in which hexagonal close‐packed structured Ru is grown on Au to form nanoparticles with 3D branches. Exposing low‐index facets on these 3D branches creates stable reaction kinetics to achieve high activity and the highest stability observed for Ru nanoparticle oxygen evolution reaction catalysts. These design principles provide a synthetic strategy to achieve stable and active electrocatalysts.

Recent Advances and Prospective in Ruthenium-Based Materials for Electrochemical Water Splitting

“…Such enhancement of OER stability could be originated from more metallic Ru in Pd–Ru core–shell nanoparticles when compared with Ru nanoparticles. Furthermore, the same group also fabricated Pd–Ru or Au–Ru nanoparticles with core–branch structure, and this class of catalysts presents more potential in improved OER stability and activity owing to exposed low-index Ru facets. , …”

Crystal facet and phase engineering for advanced water splitting

“…9c). 192 Furthermore, facet control on transition metal compounds has been investigated to approach practical use, reducing catalyst costs. Many attempts have been made to increase the active sites derived from the exposed facet of metal oxide and hydroxide.…”

Ruthenium Nanoparticles for Catalytic Water Splitting

“…Remarkably, an alternative system for improving the stability of the Ru NPs, while maintaining or even increasing their activity in the OER, has been shown to be the combination of the Ru element with a more stable noble metal, which is less prone to undergo oxidation. Thus, Tilley and co‐workers reported Pd@Ru core–shell NPs, or Pd−Ru and Au−Ru branched and faceted NPs, with η 10 values of 220–230 mV and Tafel slopes of 61–62 mV dec −1 in 0.1 m HClO 4 (Table , entries 4–6). The first study demonstrates that the Pd core stabilizes the Ru shell by up to ten times, while maintaining the activity, whereas the other two studies show that the presence of branches increases both the stability and activity of the NPs, relative to the respective bimetallic spherical systems …”