Tunable Ru‐Ru2P heterostructures with charge redistribution for efficient pH‐universal hydrogen evolution

Designing synergistic heterogeneous catalytic interfaces is the key to developing highly compatible pH‐universal electrocatalysts for complex chemical environments. Our theoretical calculation results demonstrate that the Ru‐Ru2P heterointerface can not only promote the redistribution of charges, but also reduce the d‐band center, and then enhances the adsorption capacity of the key intermediate. However, in situ and facile synthesis of Ru‐Ru2P heterostructures is severely limited by thermodynamic obstacles. Herein, we propose a molten salt‐assisted catalytic synthesis scheme, and successfully build a series of homologous metallic Ru‐Ru2P heterostructure catalysts with different molar ratios of Ru to P under atmospheric pressure and low‐temperature (400°C). The resultant Ru‐Ru2P with rich heterostructures show the Pt‐like HER performance in different pH media. Particularly, it is prominent under alkaline conditions (18 mV @ 10 mA cm−2), which outperforms the Pt catalyst (37 mV @ 10 mA cm−2). Furthermore, Ru‐Ru2P heterostructures also show certain potential in the electrolysis of seawater to produce hydrogen. This work represents a significant supplement of high‐efficiency pH‐universal HER catalysts, and provides a new light on interface engineering in energy technology fields and beyond. A low‐temperature solid phase route is formulated to form controllable Ru‐Ru2P heterointerfaces with homologous Ru where the higher electronic state crosses the Fermi level and then lowers the d‐band center, thereby allowing the catalyst with Pt‐like pH‐universal hydrogen evolution reaction kinetics.