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the CB for enhancing the formation of electron/hole pairs (Fig. 13.7a) [318]. Dyes
such as methylene blue, Azure, erythrosine, rhodamine, and crystal violet have been
widely functionalized under solar irradiation [318].
Similarly, noble metals (e.g., Ag, Ni, Cu, Pt, Rh, and Pd) with Fermi level lower
than TiO 2 catalyst have also been deposited on the TiO 2 surface for enhanced charge
separation (Fig. 13.7b) [244]. These metals were reported to enhance electron transfer, but require good knowledge on the optimal deposited amount needed during the
fabrication process. Although noble metal coupling could be efficient in prolonging
the surface charge separation, their cost-effectiveness for an industrial application is
Fig. 13.7 (a) Steps of excitation with a sensitizer in the presence of an adsorbed organic electron
acceptor (EA); (b) scheme of TiO 2 band structures, chemically ion-doped TiO 2 and physically ionimplanted TiO 2 ; (c) electron capture by a metal in contact with a semiconductor surface [205]
13 Wastewater
the CB for enhancing the formation of electron/hole pairs (Fig. 13.7a) [318]. Dyes
such as methylene blue, Azure, erythrosine, rhodamine, and crystal violet have been
widely functionalized under solar irradiation [318].
Similarly, noble metals (e.g., Ag, Ni, Cu, Pt, Rh, and Pd) with Fermi level lower
than TiO 2 catalyst have also been deposited on the TiO 2 surface for enhanced charge
separation (Fig. 13.7b) [244]. These metals were reported to enhance electron transfer, but require good knowledge on the optimal deposited amount needed during the
fabrication process. Although noble metal coupling could be efficient in prolonging
the surface charge separation, their cost-effectiveness for an industrial application is
Fig. 13.7 (a) Steps of excitation with a sensitizer in the presence of an adsorbed organic electron
acceptor (EA); (b) scheme of TiO 2 band structures, chemically ion-doped TiO 2 and physically ionimplanted TiO 2 ; (c) electron capture by a metal in contact with a semiconductor surface [205]
13 Wastewater