Applications of TiO2 nanotube arrays in environmental and energy fields: A review

Photoelectrocatalytic hydrogen production using nitrogen containing water soluble wastes

“…Of course, practically no hydrogen was produced in the absence of any additive (curve 4). The higher rate observed in the presence of urea compared to that of formamide may be justified by the higher number of hydrogen molecules generated by one molecule of urea than by one molecule of formamide, as seen by comparison of reactions (12) and (11). However, the lowest rate obtained in the presence of ammonia is in contrast with reaction (10), which indicates that more hydrogen molecules are expected by oxidation of one molecule of ammonia than by one molecule of formamide.…”

“…The Gibbs free energy change for reaction (10) is positive (DG 0 f ¼ þ26.57 kJ/mol) indicating the necessity of an important energy input, which is, of course, provided through the photocatalytic route. Interestingly, DG 0 f ¼ À42.82 kJ/mol < 0, in the case of reaction (11), which means that this reaction is exergonic, therefore, much more favorable than reaction (10). Nevertheless, reaction (12) is highly endergonic (DG 0 f ¼ þ219.9 kJ/mol) but it still leads to the highest hydrogen production rate.…”

“…Reaction (11) hides the fact that the final stage of formamide photocatalytic splitting occurs by consumption of hydroxyl radicals. This is not a sustainable reaction since it proceeds by consumption of hydroxyl ions (through reaction (4)).…”

Titanium Dioxide Modifications for Energy Conversion: Learnings from Dye-Sensitized Solar Cells

“…Additionally, enhanced light scattering and dye adsorption can be achieved by modifying the shape of NPs or mixing nanotubes, nanowires, nanospheres, and hollow TiO 2 [58,[77][78][79][80][81]. On the same note, 2D and 3D structures of TiO 2 such as nanoribbons, nanodisks, nanoleaves, nanoflowers, nanorods, hedgehog nanostructure and dendritic hollow structures have also be explored for DSCs [82][83][84][85][86][87].…”

Modification of TiO2 nanotubes by WO3 species for improving their photocatalytic activity

“…Due to long-term stability, non-toxicity, and high corrosion resistance, titanium dioxide is widely used in various fields [1], such as solar cells [2], biomedical [3], water splitting [4], gas sensors [5], self-cleaning surfaces [6], photocatalysis [7,8], etc. In the last few decades, many efforts were focused on the control of nanostructure of titania [9][10][11].…”