Nanoscale Visualization of Plasmon-Enhanced Hydrogen Activation on Pt(111) Surface

Efficient H2 activation under mild conditions is crucial for achieving energy-efficient catalytic hydrogenation but remains a major challenge. Here, we demonstrate nanoscale visualization of plasmon-enhanced H2 activation on the Pt(111) surface at room temperature under visible light by employing a combination of tip-enhanced Raman spectroscopy (TERS), density functional theory, finite element method (FEM), and quantum mechanical modeling. Time-dependent in situ TERS successfully tracked H2 activation via reductive desorption, while hyperspectral imaging revealed a 20% increase in H2 activation in 180–300 nm regions around the TERS near-field. Plasmonic heating was excluded as the origin of the enhanced H2 activation based on both experimental spectroscopic evidence and FEM simulations. Instead, first-principles quantum calculations demonstrated that hot electrons generated in the TERS near-field can drive H2 dissociation at the top, bridge, and fcc sites on the Pt(111) surface via indirect hot electron transfer mechanism. Importantly, we demonstrate that the activated hydrogen atoms on Pt(111) surface can propagate beyond the plasmonic near-field through a “crowd effect”. This fundamental study provides direct experimental evidence and mechanistic insights into plasmon-enhanced H2 activation and propagation on the Pt(111) surface, offering a new route for energy-efficient catalytic hydrogenation.