A DFT Study on Defect-Mediated Surface Modification of Titania by Grignard Reagent

Grafting organic groups on titania surfaces allows us to tailor these materials for their use as catalysts, membranes, and other applications. However, the grafting mechanism from Grignard reagents is at present not understood. In this work, we investigated the adsorption and functionalization of TiO 2 anatase surfaces by using DFT+ U calculations. Systematic screening of pristine and defective surfaces, including oxygen vacancy, Ti vacancy, and combined Ti–O vacancy, reveals that Ti vacancy and Ti–O dual vacancy are the most stable and exhibit enhanced reactivity. Adsorption and reaction energetics, supported by electronic and structural analyses, show that the Grignard reagent preferentially binds to these defect sites, promoting the formation of Ti–O–C bonds. This defect-mediated functionalization, driven by the Grignard reagent’s nucleophilic carbon center, induces substantial surface reconstruction and electronic delocalization. These findings provide molecular-level insight into vacancy-driven reactivity and highlight strategies for designing TiO 2 -based catalysts and membranes.