Gap-Enhanced Catalysis in Gold Nanostructures by Electric Field and Curvature Effects

The catalytic performance of plasmonic nanostructures is strongly influenced by surface morphology. While the antenna effect in tip regions has received considerable attention, the role of gap morphology has been largely overlooked. Comprehending morphology-regulated catalysis at the subparticle level remains constrained by morphology heterogeneity and imaging resolution limitations, hindering rational nanocatalyst design. Here, we develop a single-particle catalytic activity assay by coupling single-molecule fluorescence (SMF) imaging with plasmon-enhanced fluorescence, enabling the probing of catalytic dynamics of plasmonic Au nanostructures and their correlation with local electric fields. Using this approach, we demonstrate that nanospine formation with nanoscale gaps on Au nanostructures significantly enhances catalytic activity. Further investigations using SMF imaging, electric field simulations, and molecular dynamics simulations reveal that the gap-enhanced catalytic activity is driven by amplified electric fields and increased substrate adsorption at negatively curved sites. This study provides valuable insights into designing plasmonic nanocatalysts through surface morphology engineering.