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.