Abstract
Nitrogen substituted yellow colored anatase
TiO2−xN
x and
Fe–N co-doped Ti
1−yFe
yO
2−xN
x have been easily synthesized by novel hydrazine method. White anatase
TiO2−δ and
N/Fe–
N-doped samples are semiconducting and the presence of ESR signals at
g 1.994–2.0025 supports the oxygen vacancy and
g4.3 indicates Fe
3+ in the lattice.
TiO2−xN
x has higher conductivity than
TiO2−x and
Fe/Fe–
N-doped anatase and the UV absorption edge of white
TiO2−x extends in the visible region in
N, Fe and
Fe–N co-doped
TiO2, which show, respectively, two band gaps at
3.25/2.63,
3.31/2.44 and 2.8/2.44 eV. An activation energy of
1.8 eV is observed in Arrhenius log resistivity vs. 1/
T plots for all samples. All
TiO2 and
Fe-doped
TiO2 show low 2-propanol photodegradation activity but have significant NO photodestruction capability, both in UV and visible regions, while standard Degussa P-25 is incapable in destroying NO in the visible region The mid-gap levels that these
N and
Fe–N-doped
TiO2 consist may cause this discrepancy in their photocatalytic activities.