Two-Dimensional Palladium Nanosheet Intercalated with Gold Nanoparticles for Plasmon-Enhanced Electrocatalysis

Plasmon-enhanced electrocatalysis holds great promise for converting solar energy into chemical energy by efficiently harvesting photons for electrocatalytic reactions. Here, we report a unique two-dimensional (2D) "Egg Waffle"-like heterostructure, i.e., gold nanoparticles intercalated in a palladium nanosheet (AuNP-in-PdNS), effectively interfacing Au NPs with 2D Pd for greatly enhancing electrocatalytic activity under light illumination. A considerable electrocatalytic enhancement, i.e., a small overpotential of 19 mV (i.e., 4-fold decrease) at a current density of 10 mA cm–2 for the hydrogen evolution reaction and an improved oxygen reduction reaction with a half-wave potential of 0.882 V, is achieved on the 2D AuNP-in-PdNS heterostructure due to excitation of the localized surface plasmon resonance (LSPR). The unique heterostructure and strongly enhanced localized field intensity under LSPR excitation could result in hot electrons concentrated on the surface of Pd NSs and direct transfer of plasmonic energy to metal–adsorbate complexes, manifesting as a reduction of the apparent activation barrier in the electrocatalysis. This study provides insight into both the design of efficient electrocatalysts and the distinct role of LSPR excitation in plasmon-enhanced electrocatalysis.