Effect of co-doping and tri-doping with transition metals and a nonmetal on photocatalytic activity in visible light of TiO2 thin film

The Photocatalytic Degradation of Vehicle Exhausts by an Fe/N/Co–TiO2 Waterborne Coating under Visible Light

“…This indicates that the band gap width decreases significantly after doping, which is more conducive to improving the visible light response’s efficiency. It can be concluded that tri-doping plays an important synergistic role in the absorption of TiO 2 in the visible region [34].…”

A review on the applications of zinc tungstate (ZnWO4) photocatalyst for wastewater treatment

“…The n-type dopants, on the other hand, have more valence electrons with energies very close to the conduction band and act as electron donors. The valency of the n-type dopants is easily excited to the conduction band when they get incorporated into the semiconductor's atomic lattice (Chen et al, 2013;Phung et al, 2017).…”

“…One disadvantage of metal doping is its low quantum efficiency and thermal instability. Co-doping with two nonmetals, metal and nonmetal, and two metals reduces this problem (Phung et al, 2017). The formation goes from tri-doped > co-doped > mono-doped > pure semiconductor.…”

“…The formation goes from tri-doped > co-doped > mono-doped > pure semiconductor. When Phung et al (2017) synthesized and analyzed the effects of mono-doping, co-doping, and tri-doping on TiO 2 , the bandgap energies were also reduced significantly by forming N 2p bands close to the top of the valence band, which increased visible photocatalytic activity.…”