An Efficient Visible-Light-Sensitive Fe(III)-Grafted TiO₂ Photocatalyst

Abstract

We have prepared a TiO 2 -based novel visible-light-sensitive photocatalyst, in which Fe(III) species were grafted on a rutile TiO 2 surface (denoted as Fe(III)/TiO 2 ). With use of X-ray absorption fine structure analysis, the grafted iron species were determined to be in the 3+ state and adopt an amorphous FeO(OH)-like structure. Fe(III)/TiO 2 displayed optical absorption in the visible light range over 400 nm, which was assigned to the interfacial charge transfer from the valence band of TiO 2 to the surface Fe(III) species. Its photocatalytic activity was evaluated by the decomposition of gaseous 2-propanol under visible light (400-530 nm), which revealed a high quantum efficiency (QE) of 22%. Monochromatic light experiments indicated that the effective wavelength region was extended as far as 580 nm while maintaining a QE of greater than 10%. On the basis of the analogy to Cu(II)-grafted TiO 2 photocatalyst et al. Chem. Phys. Lett. 2008, 457, 202), we speculate that the high performance of the present photocatalyst is derived from the photoproduced holes that are generated in the valence band of TiO 2 and contribute to the oxidative decomposition of 2-propanol, and the catalytic reduction of oxygen (presumably multielectron reduction) by photoproduced Fe(II) species on TiO 2 .

TiO2 nanocluster modified-rutile TiO2 photocatalyst: a first principles investigation

“…Photocatalytic technologies have great potential as low cost, environmentally friendly catalysts for environmental depollution by destruction of organic pollutants 1,2 , removal of bacteria such as MRSA 3,4 and the interesting possibility of 30 solar hydrogen production from water splitting [5][6][7] . A leading material is titanium (IV) dioxide, TiO 2 , which is cheap, readily available and non-toxic.…”

Inhibition of the ROS-mediated cytotoxicity and genotoxicity of nano-TiO2 toward human keratinocyte cells by iron doping

“…In fact, it has been reported to both enhance electron/hole separation; thus, increasing the photocatalytic activity or increasing the rate of recombination of the charge carriers leading to a detrimental effect. The concentration of Fe 3+ ions has been shown to be a key factor since low loading increases the efficiency (Jin et al 2011;Yu et al 2010) while an high loading has generally the opposite effect (Elghniji et al 2012;Colmenares et al 2006;Wen et al 2012;Yu et al 2009;Rehman et al 2009;Fig. 7 Effect of the TiO 2 samples on the colony forming efficiency (CFE) on HaCaT cells exposed to 100 and 500 µg/mL of TiO 2 samples.…”

“…The photocatalytic efficiency of iron-doped TiO 2 is dependent upon the synthetic routes and the extent of loading. In fact, while an enhancement of the photocatalytic activity is observed for low loadings (Jin et al 2011;Yu et al 2010), high loadings may have a detrimental effect (Elghniji et al 2012; Colmenares et al 2006;Wen et al 2012;Yu et al 2009;Rehman et al 2009;Fabrega et al 2010). Manganese has also been proposed to decrease the photoreactivity of TiO 2 (Wakefield et al 2004).…”

Hydrothermal synthesis of visible light-sensitive conduction band-controlled tungsten-doped titanium dioxide photocatalysts with copper ion-grafts

“…12) 14) This system functions photocatalytically, because the interfacial charge transfer (IFCT)-induced holes in the valence band (VB) of TiO 2 decompose organic substances, while the Cu(I) [or Fe(II)] ions produced by IFCT appear to reduce adsorbed oxygen (O 2 ) through a multi-electron reduction process. 12)14) The induction of O 2 reduction by photo-generated Cu(I) [or Fe(II)] ions grafted on TiO 2 enables the conduction band (CB) of TiO 2 to be controlled, which led to the successful development of a visible light-sensitive CB-controlled Cu(II)/ Ti 1¹3x W x Ga 2x O 2 photocatalyst.…”