Hot Electrons Do the Impossible: Plasmon-Induced Dissociation of H₂ on Au

TLDR

Heterogeneous catalysis is crucial for chemistry and energy, and catalysts that harness light to drive reactions in a directed, orbital‑specific way could dramatically lower energy inputs and transform catalysis. The study demonstrates room‑temperature dissociation of H₂ on gold nanoparticles under visible‑light illumination. Plasmon‑excited Au nanoparticles generate hot electrons that transfer into a Feshbach resonance of adsorbed H₂, causing dissociation, which is monitored by detecting HD from H₂ and D₂ and by varying nanoparticle size and light wavelength. This work establishes a new route for controlling reactions on metallic catalysts.

Abstract

Heterogeneous catalysis is of paramount importance in chemistry and energy applications. Catalysts that couple light energy into chemical reactions in a directed, orbital-specific manner would greatly reduce the energy input requirements of chemical transformations, revolutionizing catalysis-driven chemistry. Here we report the room temperature dissociation of H2 on gold nanoparticles using visible light. Surface plasmons excited in the Au nanoparticle decay into hot electrons with energies between the vacuum level and the work function of the metal. In this transient state, hot electrons can transfer into a Feshbach resonance of an H2 molecule adsorbed on the Au nanoparticle surface, triggering dissociation. We probe this process by detecting the formation of HD molecules from the dissociations of H2 and D2 and investigate the effect of Au nanoparticle size and wavelength of incident light on the rate of HD formation. This work opens a new pathway for controlling chemical reactions on metallic catalysts.