Fall 2020 Shires Graduate Seminar Series

Date/Time
Date(s) - Fri 11/06/20
1:30 pm - 2:20 pm

Location
Jett Hall (JH) 259 Watkins Connected Learning Classroom

Categories


Zoom meeting ID: 989 5654 2719

Supported Atomic Catalysts for CO2 Photoreduction
Aaron Deskins
Worcester Polytechnic Institute

CO2 reduction is an important reaction for removal of this harmful gas and conversion to useful chemicals, such as methane or methanol. Sub-nanometer metals have great potential as catalysts for CO2 conversion. Traditional catalysts involve much large metal particles where most of the atoms are below the surface and do not participate in the catalytic reactions. For atomic-size catalysts, most if not all the atoms are catalytically active. Experimental results show that Cu/TiO2 photocatalysts, where the Cu exist in a highly dispersed atomic state, are very are active for CO2 reduction, more so than pure TiO2. In addition, modeling of these catalysts using density functional theory (DFT) has been crucial to understanding their properties. Our results show that several factors may lead to CO2 reduction. Small Cu clusters (especially dimers) are able to readily activate CO2. Oxygen vacancies in Cu/TiO2 catalysts readily help facilitate CO2dissociation to form CO, with barriers much lower than pure TiO2 or Cu/TiO2. The presence of photoexcited electrons further leads to stabilization of activated CO2 and reduction. Stability of Cu atoms/clusters is also important, and we address the stability of atomic-size clusters in different reaction environments. We have also performed further modeling work beyond just Cu to analyze all transition metals and identify which supported metals may be active for CO2reduction. We have also applied statistical learning models to identify which properties of metals determine their stability and activity. Our work shows that a combination of small atoms/clusters on metal oxide support, surface defects, and excited electrons may be a very promising avenue for CO2 reduction and conversion of this greenhouse gas.

Biography

Aaron Deskins is an Associate Professor at Worcester Polytechnic Institute (WPI) in the Department of Chemical Engineering. He is an expert in the modeling of materials, particularly catalysts. A large portion of his work is focused on electrocatalysis and photocatalysis. He received undergraduate degrees in Chemistry and Chemical Engineering from the University of Utah, as well as a Ph.D. from the Chemical Engineering department at Purdue University. He spent 3 1/2 years at Pacific Northwest National Laboratory as a post-doctoral researcher before coming to WPI in 2009. He currently has 59 publications. He is also now serving as vice-chair for the New England Catalysis Society, having previously served as chair.

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