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

The efficient electrochemical hydrogen evolution reaction (HER) plays a key role in accelerating sustainable H 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 PdPb nanoplate (AL-Pt/PdPb). The atomic efficiency and electronic structure of the active surface Pt layer were largely optimized, greatly enhancing the acidic HER. AL-Pt/PdPb exhibits an outstanding HER activity with an overpotential of only 13.8 mV at 10 mA/cm and a high mass activity of 7834 A/g at -0.05 V, both largely surpassing those of commercial Pt/C (30 mV, 1486 A/g). In addition, AL-Pt/PdPb shows excellent stability and robustness. Theoretical calculations show that the improved activity is mainly derived from the charge transfer from PdPb to Pt, resulting in a strong electrostatic interaction that can stabilize the transition state and lower the barrier.