Electrochemical Hydrogen Evolution Reaction Efficiently Catalyzed by Ru2P Nanoparticles

Developing alternatives to Pt catalysts is a prerequisite to cost‐effectively produce hydrogen. Herein, we demonstrate Ru2P nanoparticles (without any doping and modifications) as a highly efficient Pt‐like catalyst for the hydrogen evolution reaction (HER) in different pH electrolytes. On transferring the hexagonal close‐packed crystal structure of Ru to the orthorhombic structure of Ru2P, a greatly improved catalytic activity and stability toward HER is found owing to Ru−P coordination. The electronic state change originates from the P−Ru bonding structures, which accounts for the HER activity improvement compared with Ru nanoparticles. Specifically, Ru2P nanoparticles can drive 10 mA cm−2 at a very low overpotential of 55 mV, only 8 mV more than Pt/C in an acidic solution; and an extremely low overpotential of approximately 50 mV is needed in alkaline solution, about 20 mV less than the Pt/C catalyst. The Volmer–Tafel mechanism is indicated on Ru2P nanoparticles with the typical Tafel slope of 30 mV dec−1 of Pt metal indicating a Pt‐like catalytic ability. Ru2P is more active in the Ru‐P family as H atoms prefer to adsorb on Ru atoms rather than on the P element according to theoretical calculations. Considering the low price of Ru (20 % of Pt), anti‐corrosion ability in the electrolyte, and the safe and reliable fabrication approach, the powder Ru2P nanoparticles make an excellent HER catalyst with great promise for large‐scale water electrolysis applications. Ru having fun: Ru2P nanoparticles as a highly efficient Pt‐like catalyst for the hydrogen evolution reaction (HER) are demonstrated for the first time, which have high catalytic stability, anti‐corrosion ability, and catalytic efficiency in different pH electrolytes. The electronic state change originates from the P−Ru bonding structures, which accounts for the HER activity improvement compared with Ru nanoparticles.