A Density Functional Theory and Experimental Study of CO₂ Interaction with Brookite TiO₂

The interactions of CO 2 with the (210) surface of brookite TiO 2 were studied using first-principle calculations on cluster and periodic slab systems. Charge and spin density analyses were implemented to determine if charge transfer to the CO 2 molecule occurred and whether this charge transfer was comparable to that seen with the anatase TiO 2 (101) surface. Although the brookite (210) surface provided energetically similar CO 2 interactions as compared to the anatase (101) surface, the brookite surface had negligible charge transfer to the CO 2 molecule. This result suggests that unmodified brookite is not a suitable catalyst for the reduction of CO 2 . However, the results also suggest that modification of the brookite surface through the creation of oxygen vacancies may lead to enhancements in CO 2 reduction. The computational results were supported with laboratory data for CO 2 interaction with perfect brookite and oxygen-deficient brookite. The laboratory data, generated using diffuse reflectance Fourier transform infrared spectroscopy, confirms the presence of CO 2 – at significant levels on the oxygen-deficient brookite.