VU Physics and Astronomy Colloquium

Friday, February 8, at 3:30 PM in NSC 221. Join us for refreshments in the Planetarium at 3:05 PM.

"From Green-House Gas to Solar Fuels: Design of Photocatalysts by Computational Approach"

Dr. Haiying He, Department of Physics, Michigan Technological University

The photochemical conversion of CO2 and H2O into energy-bearing hydrocarbon fuels provides an attractive way of mitigating the green-house gas CO2 and utilizing solar energy as a sustainable energy source. However, due to the high chemical inertness of CO2 molecules, the conversion rate of CO2 is impractically low. A thorough understanding of reaction mechanisms is indispensable for the design of new high-efficiency and high-selectivity catalysts. By carrying out first-principles calculations, we have studied the initial step of CO2 activation and 2e reduction on anatase (101) surfaces. It is shown that anatase plays a critical role in adsorbing CO2 and facilitating electron and proton transfer from the surface to CO2 in the process of photochemical reduction of CO2, in addition to its role of generating and separating electron-hole pairs during photoexcitation. Our materials screening based on the computational approach suggests that surface doping of Ti cation sites by metal species M can substantially lower the reaction barrier to activate CO2. An empirical model is proposed to correlate the reactivity of the M-doped surface with its physical properties.