Fe-doped and ZnO-pillared titanates as visible-light-driven photocatalysts

Heterostructured Tin oxide-pillared tetratitanate with enhanced photocatalytic activity

“…Each of the 4.1 nm peak in sol-H 2 Ti 4 O 9 and 3.6 nm in SnO 2 -H 2 Ti 4 O 9 displays a wide pore distribution, which may be originated from the house-of-cards aggregation between the pillared nanocomposite crystallites with the metal oxide nanoparticles. The observations are similar to that in the previous pillared materials [28,33,34]. The pillared structure, fabricated from the alternating arrangement of -host-guest-host-, is favorable for coupling two semiconductors with each other, which is expected to be much efficient for the photocatalysis by suppressing the recombination of photo-generated electrons and holes.…”

“…In general, there is an extremum corresponding to the gallery height in the pore size distribution of a pillared layered compound, which is derived from the platelet stacking of sheets pillared by the intercalated guest particles in the pillared structure. Such case has been observed in TiO 2 -and SnO 2 -hexaniobates [11,14], CrO x -, ZnO-and TiO 2 -titanates [12,28,33], SnO 2 -tantalotungstate [13], and SiO 2 -MFI zeolite [34]. Nevertheless, it is not encountered in the as-prepared sol-H 2 Ti 4 O 9 .…”

“…Such observation is an evidence of the formation of a heterostructure consisting of exfoliated Ti 4 O 2À 9 nanosheets and nanometer-sized SnO 2 particles. It is noted that the (200) and (300) reflections of the pillared titanate are not clear, illustrating that most of the exfoliated nanosheets are randomly hybridized with SnO 2 nanoparticles to form the house-of-cards type stacking of the restacked nanohdrid [28], which was supported by the results of pore size distribution measurements. After calcination, the three (h00) reflections are shifted toward higher angles of 4.0°, 8.4°and 12.2° (Fig.…”

Enhanced Photocatalytic Activity of Iron-Doped ZnO Nanowires for Water Purification

“…Finally, these OH • radicals having a strong oxidation power, can lead to a partial or complete mineralization of the organic substances (such as the dyes, for example) in the waste water, forming non-toxic products such as CO 2 and H 2 O, as shown in Equation (11).…”

“…One of the effective methodologies to increase the photocatalytic activities of ZnO, by increasing the visible-light absorption, is the doping of the ZnO nanostructure with transition-metals [10,11], due to the band gap narrowing resulting from the creation of dopant energy levels below the CB [12,13]. This technique has, on the one hand, the advantage of effectively preventing the recombination of photo-generated electron-hole pairs; and on the other hand, can extend the photocatalysis' spectral range, leading to the improvement of the semiconductor photocatalytic activities.…”