Insights into enhanced O3 adsorption on Ti/ anatase TiO2 (1 0 1) surfaces by positive electric Fields: A theoretical exploration

Enhanced ozone (O3) adsorption at catalyst surfaces is an important prerequisite and key step in enhancing heterogeneous O3 catalysis (catazone) and promoting the production of reactive oxygen species (ROS). This study proposes a new strategy to enhance O3 adsorption via application of a positive electric field. The enhanced mechanism was systematically revealed using first-principles density functional theory calculations. Taking the previously studied Ti/anatase TiO2 (1 0 1) electrode as an example, the effects of an electric field strength ranging from 0 V Å−1–1 V Å−1, adsorption site type, and adsorption configuration on the adsorption energy (Eads) were investigated. By resolving the electronic structure changes and orbital composition, the enhanced mechanism of bonding of O3 to the active sites was further elucidated. The results confirmed that the application of a positive electric field significantly increased Eads, and the adsorption sites and configurations played an important role. At 1 V Å−1, Eads was significantly increased by highest value of 179 %, the bimolecular sites such as double water molecules and hydroxyl groups, ≡(H2O)2, ≡(OH)2 achieved high Eads of −4.16 eV, and −3.04 eV, respectively, than the values of −2.58 eV and −2.72 eV for monomolecular sites, ≡H2O or ≡OH, while the bridging configuration attained an Eads value 61.24 % higher than the single-armed configuration. This is mainly because the applied positive electric field can enhance charge enrichment at the adsorption sites by promoting the charge transfer and orbital hybridization between them and the O3 molecules to form new bonds with lower Fermi energy levels, ultimately achieving enhanced O3 adsorption. This theoretical study provides new insights into enhancing O3 adsorption for better catazone and fundamental guidance for subsequent experimental research.