Unlocking Plasmonic Hot Electron Utilization on Palladium Nanoparticles via Modulation of the Bimetallic Interface for Enhanced Photocatalysis

Plasmonically generated hot electrons hold significant promise as nonthermal energy sources for driving chemical transformations, yet their catalytic efficacy is fundamentally constrained by the intrinsic Fermi level (EF) limitations of noble metals. Using palladium (Pd) as a model system─a material renowned for its exceptional catalytic activity but restricted by its low EF (≈ −5.1 eV)─we demonstrate a rational interfacial engineering strategy to amplify hot electron energy and reaction performance. By integrating copper (Cu) into Pd nanostructures, we achieve a 0.45–75 eV elevation in hot electron energy through tailored Cu–Pd interfacial electronic modulation. This advancement unlocks previously inaccessible reaction pathways, most notably enabling a direct four-electron reduction process on CuPd Janus nanoparticles synthesized via in situ Cu growth on Pd(111) surfaces, a mechanism absent in pure Pd systems. Furthermore, the introduction of Pd (100) facets synergistically enhances catalytic efficiency, elevating Suzuki coupling conversion from 65 to 94% while achieving a 1.6-fold acceleration in reaction kinetics. Combining in situ electrochemical surface-enhanced Raman spectroscopy and theoretical calculations, we quantify that the hot electron energy level of Pd increases from −5.11 to −4.66 eV, with an increase of 0.45 eV, thereby optimizing hot electron transfer dynamics and redox potentials. This work provides a paradigm-shifting approach to plasmonic photocatalyst design, emphasizing dual control over hot electron energetics and interfacial charge transfer pathways as critical levers for overcoming inherent material limitations in energy-conversion applications.