Effect of Cr 3+ concentration on structural and optical properties of TiO 2 :Cr 3+ anatase and rutile phases

Effects of Ag0-modification and Fe3+-doping on the structural, optical and photocatalytic properties of TiO2

“… 15,16,34,36,37 On the other hand, the substitutions of Ti 4+ ions with Fe 3+ ions form impurity energy levels between the conduction band and valence band in the forbidden band, thereby decreasing the E g . 5,7,10,21,33,43,51 Therefore, the change of E g is not the main reason for the decreased photocatalytic performance of Fe–TiO 2 and 1% Ag/1% Fe–TiO 2 .…”

“…Firstly, with a wide energy gap of 3.2 eV, TiO 2 only absorbs ultraviolet light with a wavelength of less than 387 nm, therefore, the utilization rate of sunlight is limited. 5–9 Secondly, the high recombination rate of photogenerated electrons and holes results in low quantum yield. 10–12 …”

Characterizations of Cr3+- doped SnO2 Powders Via a Hydrolysis Method

“…6A, the PL spectrum excited by 560 nm wavelengths of the sample annealed at 1200 o C consists of a very prominent narrow emission peak at 695 nm and three weaker peaks at 670, 708, and 715 nm. The emission peak at 695 nm is believed to be related to the transition from the 2 E ( 2 G) excited state to the 4 A2( 4 F) ground state within Cr 3+ ions located in the octahedral field of SnO2 host and very weak peaks at 670, 708, 715 nm being its phonon-sidebands [26,27]. The PLE spectrum of the sample annealed at 1200 o C and monitored at 695 nm exhibits two bands in the 375-475 nm and 475-625 nm ranges with peak positions of ≈ 410 nm and ≈ 560 nm, respectively.…”