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.
Bibliographical noteFunding Information:
P.C. acknowledges funding from the Air Force Office of Scientific Research MURI Grant FA9550-15-10022, Army Research Office PECASE Grant W911NF-19-1-0116, and the Catalysis Center for Energy Innovation, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award DE-SC0001004. H.R. acknowledges the Postdoctoral Fellowship support by Arnold O. and Mabel Beckman Foundation. I.B.A. acknowledges the support from the National Science Foundation (NSF) under the Graduate Research Fellowship Program (GRFP). The UCSB MRL Shared Experimental Facilities are acknowledged for use of the TEM. M. Gordon at UCSB is acknowledge for help with setting up and calibrating the light chopping apparatus.