Unique Surface Chemical Species on Indium Doped TiO₂ and Their Effect on the Visible Light Photocatalytic Activity

Abstract

TiO 2 doped by different contents of indium was prepared by the sol-gel method by using titanium(IV) tetrabutoxide and indium chloride as precursors. It was revealed that a unique chemical species, O-In-Cl x (x ) 1 or 2), existed on the surface of the indium doped TiO 2 . The surface state energy level attributed to the surface O-In-Cl x species was located at 0.3 eV below the conduction band of TiO 2 . The transition of electrons from the valence band of TiO 2 to the surface state energy level was responsive to visible light. The photogenerated carriers generated under visible light irradiation can be efficiently separated by the surface state energy level of the O-In-Cl x species and the valence band of TiO 2 to contribute to the photocatalytic reaction. Consequently, the indium doped TiO 2 showed improved photocatalytic activity for photodegradation of 4-chlorophenol compared to pure TiO 2 under visible light irradiation.

A Facile Platform for Photocatalytic Reduction of Methylene Blue Dye By CdSe-TiO2 Nanoparticles

“…Synthesis of TiO 2 TiO 2 nanoparticles were prepared by economical non-hydrolytic sol-gel route [14]. Ten millilitre of titanium tetra-isopropoxide (Spectrochem, India) was added to 40 ml of 2-methoxy ethanol (SRL Chemical, India) used as solvent and magnetically stirred at room temperature with addition of few drops of 1.0 M HNO 3 to maintain the pH value at 3.…”

Shallow and deep trap emission and luminescence quenching of TiO2 nanoparticles on Cu doping

“…After the remarkable success of Fujishima and Honda on the photocatalytic water splitting of water by TiO 2 anode, extensive research works are carried out on photocatalytic property of TiO 2 (Fujishima and Honda 1972;Yang et al 2010;Wang et al 2009;Choi et al 1994). Pure TiO 2 is only UV sensitive because of its large band gap (3.0-3.2 eV), which makes it inefficient to utilize solar light for visible light photocatalysis (Yang et al 2010;Wang et al 2009).…”

Enhanced photocatalytic hydrogen production from water–methanol mixture using cerium and nonmetals (B/C/N/S) co-doped titanium dioxide

“…The photogenerated electrons are trapped by oxygen vacancies by non-radiative combinations [42]. The decreasing emission intensity order can be attributed to increased oxygen vacancies resulted by increasing substitution effects from B to N as discussed in earlier section.…”

“…The bands at 450 and 468 nm can be attributed to free excitons, and emission peaks at longer wavelength of 481 and 492 nm can be attributed to the bound excitons [40,41]. The bound excitons result due to the presence of oxygen vacancies [40,42,43]. It can be observed from the Fig.…”