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Using Photons to Influence Catalysis on Supported Metal Catalysts

Tuesday, December 6, 2022
9:30 am - 10:30 am

Location: NHB 1.720

Supported metal catalysts, consisting of transition metals dispersed on high surface area oxide supports, are ubiquitously used in the manufacturing of chemicals and fuels. Efforts by industrial and academic researchers to improve catalytic process efficiency (higher rates and/or selectivity at lower temperature and pressure) typically focus on tuning the composition or structure 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 cause significant changes to catalytic reaction selectivity, rate, and apparent kinetic parameters. Mechanistic studies suggest that photons influence catalytic processes by redistributing charge within adsorbate-metal bonds, thereby changing elementary step energetics. Further, we have observed in some cases that using pulsed photons, rather than a continuous photon flux, allows for promoted catalytic rates with higher photon utilization efficiency. Given that modern LEDs are efficient, cheap, and programmable with on-times of sub-ms to sec and frequencies > 100 MHz, this work suggests that photon promoted or mediated chemistry may offer interesting opportunities for promoting the sustainability of chemical conversion processes. In this work I will highlight some of our work in this area and provide some thoughts on opportunities and challenges with using light to promote or drive chemistry on supported metal catalysts.

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 in the Chemical Engineering Department and the Mellichamp Chair in Sustainable Manufacturing. He currently serves as a Senior Editor for ACS Energy Letters. His research interests are in sustainable chemical conversion, heterogeneous catalysis by supported metals, atomically dispersed metal catalysts, dynamic behavior of catalysts, and photocatalysis by supported metals. He has been given various awards including the Presidential Early Career Award for Scientists and Engineers (PECASE), ACS CATL Division Early Career in Catalysis Award, AIChE CRE Division Young Investigator Award, and Ipatieff Prize from the ACS.

Speaker: Dr. Phillip Christopher, UC Santa Barbara