Plasmonic Ag Interlayer Induced Direct Energy Transfer Studied at Single-Particle Level

The surface plasmon resonance (SPR) effect of plasmonic nanoparticles can enhance photochemical transformation by facilitating energy and charge transfer between catalysts and reactants. However, the detailed mechanisms of the energy and charge transfer process are not well understood. Herein, Au-Ag@Pd nanorods (NRs) and Au@Pd NRs were designed and synthesized to explore the plasmon-induced interfacial interaction and energy- and charge-transfer mechanism for formic acid (FA) dehydrogenation. The strong adsorption of FA on Au-Ag@Pd NRs was demonstrated by finite difference time domain (FDTD) simulations and density functional theory (DFT) calculations. Importantly, wavelength-dependent measurements and in situ monitoring of FA dehydrogenation at the single-particle level indicated that the introduction of a Ag interlayer alters the energy transfer mechanism for FA dehydrogenation, which is direct energy transfer for Au-Ag@Pd NRs and indirect energy transfer for Au@Pd NRs. This work provides a deep understanding of the plasmon energy transfer process between catalysts and reactants.