Speaker
Details

Supported metal catalysts, consisting of transition metal nanoparticles on high surface area, insulating oxide supports, are ubiquitously used in the manufacturing of chemicals and fuels, as well as pollution abetment. Efforts primarily focus on improving catalytic performance (higher rates and/or selectivity at lower temperature and pressure) by tuning the composition of the catalytic materials. Alternatively, we (and others) have observed that visible photon illumination of metal nanoparticle and single atom catalysts (Pt, Cu, Ag, Rh etc.) on insulating oxide supports (Al2O3, SiO2) can induce significant changes to catalytic reaction selectivity, rate, and apparent kinetic parameters. Mechanistic studies suggest that photons influence catalytic processes by transiently redistributing charge within adsorbate-metal bonds, thereby changing elementary step energetics, akin to photolysis of organometallic complexes.
However, there is essentially no understanding of bond specificity in of the influence of visible photons on elementary step kinetics on metal nanoparticle surfaces. Further, predictive models of elementary step kinetics that include reaction temperature, pressure, and photon excitation characteristics (time dependent flux and wavelength) are missing.
In this talk I will broadly discuss experimental observations that suggest visible photon fluxes act as distinct energy sources for control catalysis on metal nanoparticle surfaces. Then, I will highlight recent efforts in our group aimed at addressing these topics of bond specificity and predictive kinetic models of photon driven chemical reactions on metal nanoparticle surfaces through analysis of the chemistry of CO on Pt and Pd nanoparticle surfaces.