Engineering the Electronic Structure of Submonolayer Pt on Intermetallic Pd₃Pb via Charge Transfer Boosts the Hydrogen Evolution Reaction

The efficient electrochemical hydrogen evolution reaction (HER) plays a key role in accelerating sustainable H₂ production from water electrolysis, but its large-scale applications are hindered by the high cost of the state-of-the-art Pt catalyst. In this work, submonolayer Pt was controllably deposited on an intermetallic Pd₃Pb nanoplate (AL-Pt/Pd₃Pb). The atomic efficiency and electronic structure of the active surface Pt layer were largely optimized, greatly enhancing the acidic HER. AL-Pt/Pd₃Pb exhibits an outstanding HER activity with an overpotential of only 13.8 mV at 10 mA/cm² and a high mass activity of 7834 A/g_Pd+Pt at -0.05 V, both largely surpassing those of commercial Pt/C (30 mV, 1486 A/g_Pt). In addition, AL-Pt/Pd₃Pb shows excellent stability and robustness. Theoretical calculations show that the improved activity is mainly derived from the charge transfer from Pd₃Pb to Pt, resulting in a strong electrostatic interaction that can stabilize the transition state and lower the barrier.