Abstract

In anatase TiO<inf>2</inf>, various passivated co-dopants such as (V–N), (Mo–C), (Nb–N), (Ta–N), and (F–N) are of significant interest due to their enhanced photocatalytic activities under visible light. Unlike the bulk phase, the effect of co-dopants in TiO<inf>2</inf> nanoparticles still lacks fundamental exploration. To understand this, we perform density-functional-theory calculations within the PBE generalized gradient approximation with corrections for the on-site Coulomb interaction (PBE + U) as well as hybrid functional (HSE06) approaches to investigate potential co-doping species and their locations in TiO<inf>2</inf> nanoparticles that could be suitable for applications as antibacterial agents or for the degradation of organic pollutants. To allow an effective comparison with experiments, the criteria are set based on the experimentally measured band edge positions of TiO<inf>2</inf> nanoparticles and the redox potentials of the reactive oxygen species of interest. Based on the analysis of donor and acceptor levels derived from thirty co-dopants, we find that the vanadium-nitrogen (V<inf>Ti</inf>–N<inf>O</inf>) pair in the T2 configuration is the most suitable passivated co-dopant for enhanced photocatalytic activity as it can reduce the band gap of TiO<inf>2</inf> nanoparticles while still providing a thermodynamic driving force for redox reactions to generate reactive oxygen species.