Description:

The Chemical and Biological Engineering Department is pleased to present a seminar by Phillip Christopher from University of California, Santa Barbara as part of our ChBE Seminar Series.

Dr. Christopher will present a seminar titled "Influence of visible photons on catalytic reactions at metal nanoparticle surfaces."

ABSTRACT: 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 for 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 and methanol on Pt and Pd nanoparticle surfaces.   

Phillip Christopher earned his B.S. in chemical engineering from University of California, Santa Barbara in 2006 and his M.S and Ph.D. in chemical engineering from University of Michigan in 2011 working with Prof. Suljo Linic. From 2011-2017 he was an Assistant Professor at University of California, Riverside. In 2017 he moved to the University of California, Santa Barbara where he is a Professor and Vice Chair for Undergraduate Affairs in the Chemical Engineering Department and the Mellichamp Chair in Sustainable Manufacturing. He serves as a Senior Editor for ACS Energy Letters. His research interests are in sustainable chemical conversion, heterogeneous catalysis by supported metals, dynamic behavior of catalysts, and photocatalysis by metal nanostructures. He has been given various awards including the Presidential Early Career Award for Scientists and Engineers (PECASE), AIChE CRE Division Young Investigator Award, and Ipatieff Prize from the ACS. 

Bagels and coffee will be provided at 9:30am, and the seminar will start at 9:40am. Please plan to arrive on time to grab a bagel and mingle!

*Please note that there will be no Zoom option for seminars this year.