A Density Functional Theory\nand Experimental Study\nof CO₂ Interaction with Brookite TiO₂

Abstract

The interactions of CO₂ with the (210) surface\nof brookite\nTiO₂ were studied using first-principle calculations on\ncluster and periodic slab systems. Charge and spin density analyses\nwere implemented to determine if charge transfer to the CO₂ molecule occurred and whether this charge transfer was comparable\nto that seen with the anatase TiO₂ (101) surface. Although\nthe brookite (210) surface provided energetically similar CO₂ interactions as compared to the anatase (101) surface, the brookite\nsurface had negligible charge transfer to the CO₂ molecule.\nThis result suggests that unmodified brookite is not a suitable catalyst\nfor the reduction of CO₂. However, the results also suggest\nthat modification of the brookite surface through the creation of\noxygen vacancies may lead to enhancements in CO₂ reduction.\nThe computational results were supported with laboratory data for\nCO₂ interaction with perfect brookite and oxygen-deficient\nbrookite. The laboratory data, generated using diffuse reflectance\nFourier transform infrared spectroscopy, confirms the presence of\nCO₂^– at significant levels on the oxygen-deficient\nbrookite.