Uncovering the Role of the Local Electric Field in Plasmon-Induced Activation of Inert C-F Bonds.

Plasmonic catalysis offers a promising route to solar-driven chemical transformations, yet its efficiency is severely limited by the high energy barrier for hot electron utilization, particularly for activating inert bonds. While recent progress suggests that the plasmonic local electric field can synergize with hot carriers to enhance reactivity, the specific contribution of the local electric field to bond activation remains unclear. Herein, we observed the visible-light-driven cleavage of the C-F bond under the intense local electric field of the Ag interparticle gaps via in situ surface-enhanced Raman spectroscopy (SERS). The relationship between nanoparticle size-dependent local electric field enhancement/hot carrier generation efficiency and C-F bond cleavage kinetics demonstrates that the local electric field can effectively lower the energy barrier for hot electron injection into adsorbate's lowest unoccupied molecular orbital (LUMO). Density functional theory (DFT) calculations further suggest that the contribution of the local electric field (CF) to the barrier reduction is at least 25% under our experimental conditions by lowering the adsorbate LUMO level. These insights deepen the mechanistic understanding of plasmonic catalysis, such as the superlinear dependence of the reaction rate on light intensity, presenting the local electric field as a critical design parameter for high-efficiency plasmonic catalysts targeting inert chemical bond activation.