TiO2 has been reported to exhibit superior catalytic, photocatalytic and biochemical activities due to its unique physicochemical properties. Specifically, catalytic activities of TiO2-based materials are driven by its reversible exchange of oxygen between various surface sites. The availability of lattice oxygen for the surface adsorbed CO, H2 and NO species participates in the catalytic conversion processes to produce CO2 and OH groups. The objective of the present work is to investigate the structure-property relationships of anions (C and N)-substituted TiO2 using density functional theory (DFT+U) approach. The synergistic effect of metal (Pd) and nonmetals (C and N)-substitution and oxygen vacancy formation on the thermal stability and energetic favorability of TiO2 was studied. Different sites were explored for the oxygen vacancy creations in bulk as wells as on the surface exposed (001) and (100) planes of TiO2. Differential bonds formation was observed between 1.92-2.03 Å for (001) exposed plane whereas the Ti-O bonds were distributed between 1.85-2.17 Å in case of (100) plane. Net oxygen activation (NOA) was found to be 23.8 and 17 % for C and N-substituted TiO2 whereas it was 23.8 and 25.6 % for Pd/C and Pd/N-codoped TiO2, respectively. The energy requirements were ranging between 5.78-12.87 eV, 4.91-6.56 eV and -4.2 to -4.8 eV for C, N and Pd/C-substituted TiO2.

Synergistic effect of anions (C and N), cation (Pd) substitution and oxygen vacancies on the oxygen activation capacity of TiO2

2019 Fall National Meeting

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