Dynamic Control of Elementary Step Energetics via Pulsed Illumination Enhances Photocatalysis on Metal Nanoparticles

Abstract

Photon illumination of metal nanoparticle catalysts can promote reaction rate and selectivity through transient charge transfer to adsorbed species. Here we demonstrate that illumination of 2 nm diameter Pt nanoparticle catalysts with pulsed visible light enhances time-averaged rates of H2 production via methanol decomposition compared with static illumination. Based on CO temperature-programmed desorption, in-situ FTIR, and kinetic measurements, we propose that pulsed illumination promotes reaction rates compared to static illumination by oscillating the binding energy of surface intermediates at frequencies that are in resonance with reaction kinetics. We also show that the impact of light is chemically specific, influencing some elementary step energetics more than others. Our results suggest that using light pulses to dynamically control the energetics of elementary steps on catalytic surfaces may enable higher activity or selectivity than is possible with static illumination or dictated by linear free energy scaling relations.

Non-Faradaic Promotion of Ethylene Hydrogenation under Oscillating Potentials

“… 22 A thorough microkinetic analysis was provided by Dauenhauer and co-workers, demonstrating the possibility of enhancing catalytic rates by orders of magnitude by the application of time-variant external stimuli corroborated by DFT. 23 − 27 Experimental proof for the efficiency of dynamic catalytic processes has so far been provided solely for dynamic photocatalytic 28 and Faradaic electrocatalytic reactions. 29 − 32 …”

Catalytic Resonance Theory: Negative Dynamic Surfaces for Programmable Catalysts

“…[17] Enhancing catalytic rates above the Sabatier maximum for these energy-related chemistries requires a new approach to catalysis, such as forced catalyst dynamics (i.e., programmable catalysts). As previously shown via simulation [18,19] and demonstrated by experiment with both dynamic photocatalysis [20] and dynamic electrocatalysis, [21] oscillating the binding energy of adsorbates on a catalytic surface accelerates the time-averaged turnover frequency orders of magnitude above the static maximum rate. This dynamic catalyst response depends on the selected applied oscillation frequency and amplitude, with a band of frequencies resonant with the underlying reaction kinetics yielding the highest catalytic rates.…”

Plasmonic enhancement of molecular hydrogen dissociation on metallic magnesium nanoclusters

“…Plasmonic properties can be harnessed for catalysis in a continuous and pulsed illumination regime. 60 In both cases, the largest concentration of high-energy electrons builds up at ∼3 eV above the Fermi energy and the largest concentration of holes is produced at ∼1 eV below the Fermi level. This particular distribution of EHPs can be connected to the Mg electronic bandstructure, which exhibits weakly dispersed valence bands close to the Fermi energy between M and L and at Γ high symmetry points from which many electrons can be transferred into a high density of conduction bands at around 2 to 4 eV above the Fermi level (see Supporting Figure S1).…”