Photocatalytic behavior of TiO 2 films synthesized by microwave irradiation

Photocatalytic TiO2 Nanorod Spheres and Arrays Compatible with Flexible Applications

“…The nanorod spheres produced at 80 • C with water presented significant structural differences, and it can be expected that these dissimilarities are related to the nanorod sphere evolution along synthesis. The compact structure is more likely to occur as it was observed previously for synthesis using water as solvent [5]. Moreover, with the temperature increase, spherical, larger and more compact spheres were observed, supporting the assumption of evolution to compact structures.…”

“…The band gaps were 3.05 eV, 3.00 eV, 3.06 eV, and 3.03 eV for 80 An analogous study, demonstrated that the ZnO seed layer deposited by spin-coating and annealed at 200 • C, resulted in an optical band gap value of 3.26 eV [64]. Structural characteristics as array thickness and compactness can also largely influence the final band gap value [5], which may justify the differences observed. The presence of other phases with larger band gaps than rutile (brookite in the case of the 80 • C H 2 O nanorod arrays) could also have played a role in the higher band gap observed; nevertheless, this effect was not confirmed for the nanorod spheres, and thus a direct relation cannot be inferred.…”

“…These spheres are formed during synthesis, as the nanorods produced initially in solution having the rutile phase, tend to aggregate in spheres in order to reduce the surface energy [60]. Thus, the nanorod spheres observed after microwave synthesis for all conditions studied are believed to have the rutile phase, with the individual TiO 2 nanorods having a [001] growth direction, such as previous related studies [5,63]. The nanorod spheres produced at 80 • C with water presented significant structural differences, and it can be expected that these dissimilarities are related to the nanorod sphere evolution along synthesis.…”

“…The photocatalytic activity depends on several properties such as band gap, crystallite size, crystalline phase, specific surface area and active facets [5,13]. The TiO 2 active facets are {110} > {001} > {100} for rutile [22] and {210} for brookite [17].…”

“…However, recently, this material has been widely used as photocatalyst agents [4][5][6][7][8][9][10]. The great interest in TiO 2 as photocatalyst is related to its low-cost, non-toxicity, high stability and photoactivity, and earth-abundance [5][6][7][11][12][13][14][15].…”