Mechanistic insights into facet-dependent CO adsorption and vibrational responses on anatase TiO2: periodic quantum-mechanical calculations

CONTEXT: ] site. Surface oxygen atoms are key contributors to π-backdonation. The results highlight the critical role of surface topography and coordination environment in governing CO adsorption behavior, extending previous insights into anatase surface chemistry. METHODS: All periodic calculations were performed using the Vienna ab initio package (VASP), employing the GGA-PBE functional and a plane-wave basis set, with the projector-augmented wave (PAW) method for the description of core electrons. All cluster calculations were performed using the ORCA package. We employed the PBE and B3LYP functionals, as well as the MP2 wavefunction-based method, all with the TZVP basis set. For the localized average ionization energy (ALIE), we employed the CCSD(T)/aug-cc-pV5Z level of theory.