Expanding the Plasmonically Activated Volume for Enhanced Fast Carrier Extraction in Au/CeO ₂ Photocatalysts

side from interface-confined plasmonic excitation into a spatially extended, volume-activated process. meV-resolution electron energy-loss spectroscopy visualizes LSPR propagation throughout the porous framework, while photoluminescence spectroscopy reveals an enhanced contribution from fast charge-transfer channels. Quantitative analysis establishes the correlation among the PAV, fast charge transfer, and carrier utilization efficiency. These findings highlight the importance of semiconductor-side carrier dynamics in plasmonic heterostructures and establish dielectric-environment engineering as an effective strategy for extending plasmonic functionality beyond the immediate metal-semiconductor interface.