Room-Temperature Synthesis of Sub‑2 nm Ultrasmall Platinum–Rare-Earth Metal Nanoalloys for Hydrogen Evolution Reaction

To tune the activity of Pt alloy electrocatalysts and reduce the Pt loading, researchers have intensively studied alloys of Pt with late transition metals. However, Pt alloy formation with rare-earth (RE) elements through the traditional chemical route is still a challenge due to the vastly different standard reduction potentials. Here, we report a universal chemical method to prepare a series of Pt/RE (RE = La, Ce, Pr, Nd, Eu, Gd, Tb, Dy, Lu) nanoalloys with tunable compositions and ultrasmall particle sizes (sub-2 nm). These Pt–RE nanoalloys were synthesized by a strong liquid metal reduction with high-speed shearing assistance at room temperature. Among the nine Pt–RE alloy catalysts, the PtNd/C shows the best hydrogen evolution reaction (HER) activity, stability, and durability compared to commercial Pt/C. The PtNd/C shows an overpotential of 25.9 mV at the current density of 10 mA/cm2 with a Tafel slope of 19.5 mV/dec and excellent stability in the acidic medium. This work not only provides a general and scalable strategy for synthesizing noble metal–RE alloys but also highlights noble metal–RE alloys as sufficiently advanced catalysts and accelerates the research of noble metal–RE alloy in energy-related applications.