Phase Engineering of a Ruthenium Nanostructure toward High-Performance Bifunctional Hydrogen Catalysis

The physicochemical properties and catalytic performance of transition metals are highly phase-dependent. Ru-based nanomaterials are superior catalysts toward hydrogen evolution reaction (HER) and hydrogen oxidation reaction (HOR), but studies are mostly limited to conventional hexagonal-close-packed (hcp) Ru, mainly arising from the difficulty in synthesiz-ing Ru with pure face-centered-cubic (fcc) phase. Herein, we report a crystal-phase-dependent catalytic study of MoOx-modified Ru (MoOx-Ru fcc and MoOx- Ru hcp) for bifunctional HER and HOR. MoOx-Ru fcc is proven to outperform MoOx-Ru hcp in catalyzing both HER and HOR with much higher catalytic activity and more durable stability. The modification effect of MoOx gives rise to optimal adsorption of H and OH especially on fcc Ru, which thus has resulted in the superior catalytic performance. This work highlights the significance of phase engineering in constructing superior electrocatalysts and may stimulate more efforts on phase engineering of other metal-based materials for diversified applications.

Automated summary

The physicochemical properties and catalytic performance of transition metals are highly dependent on their crystal phases. In this study, MoOx-modified Ru with different crystal phases (fcc and hcp) were investigated for the hydrogen evolution reaction (HER) and hydrogen oxidation reaction (HOR). It was found that MoOx-Ru fcc exhibited superior catalytic activity and durability compared to MoOx-Ru hcp. This enhancement in performance was attributed to the optimal adsorption of H and OH on fcc Ru. This work emphasizes the importance of phase engineering in developing superior electrocatalysts.