Novel synthesis of ZrxTi1-xOn mixed oxides using titanyl sulphate and pressurized hot and supercritical fluids, and their photocatalytic comparison with sol-gel prepared equivalents

Photocatalytic Nanoparticulate ZrxTi1‐xO2 Coatings with Controlled Homogeneity of Elemental Composition

“…In general, one could expect the band gap variation in this binary oxide from well known 3.2 eV of anatase TiO 2 to 5.1 eV of ZrO 2 . This tendency has been confirmed in previous studies of these mixed oxide solids . Our spectral measurements presented in Figure showed no significant variation of the band gap energy of Zr x Ti 1‐x O 2 with the increase of x from 0 to 0.3, while a stronger increase of E g appeared at a higher Zr content x>0.4.…”

Ambient temperature ZrO2-doped TiO2 crystalline photocatalysts: Highly efficient powders and films for water depollution

“…Indeed, it is possible to calculate the conduction and valence band potentials [55][56][57] of TiO2 and ZrO2 with the estimated band gap (Table 1 and Figure 5) for TiO2 and the value of 5.2 eV for the ZrO2 as reported in many studies [19,55,58]. The calculated energy levels for both oxides are represented in Figure 8.…”

“…The doped samples present slightly higher values of the band gap than the pure TiO2. This shift can be due to the use of ZrO2 [21,22], a semiconductor with a higher band gap than TiO2 (5.2 vs. 3.2 eV) [19].…”

“…Most works consisted in modifying TiO2 materials by doping with different elements or molecules such as Ag [8], P [9], N [6,10], Fe [11], and dye photosensitive molecules [12] as porphyrin [13,14]. Titania has also been combined with other semiconductor such as ZnO [15,16], SnO2 [17], CeO2 [18] or ZrO2 [19] in order to increase the specific surface, the photocatalytic activity or decrease the formation of free radicals. Regarding the ZrO2-TiO2 combination, it has been previously reported that zirconia doping increases the specific surface area [20,21], the surface acidity [22], the transition temperature between anatase and rutile [21][22][23], the adsorption and the hydrophilic properties [20,24].…”

“…Regarding the ZrO2-TiO2 combination, it has been previously reported that zirconia doping increases the specific surface area [20,21], the surface acidity [22], the transition temperature between anatase and rutile [21][22][23], the adsorption and the hydrophilic properties [20,24]. However, in most studies [19,[21][22][23], the doped materials require a calcination step to obtain crystalline materials.…”