Visible-Light Photocatalysis by Modified Titania

Abstract

Platinum or nitrogen may effectively convert titania into a semiconductor photocatalyst active in the visible. This Highlight explains how to achieve that, what electronic structure results and how these photocatalysts may be used for detoxification of pollutants D (see Scheme) for example.

Modification of Titanium Dioxide with Platinum Ions and Clusters: Application in Photocatalysis

“…Doping with Pt(IV) does not improve the photocatalytic activity of P25 under UV−visible light for RB degradation. The same result under UV−visible light was also obtained by Kisch et al ,, According to the literature, Degussa P25 catalytic properties could not also be improved by Pt(IV) doping 2 Degradation of RB (10 -4 M RB initial concentration) with pure or modified P25 titania (1 g/L photocatalyst) (surface modified and nonmodified with Pt salt (II), PtCl 4 2- ; Pt salt (IV), PtCl 6 2- ; Pt cluster, [Pt 3 (CO) 6 ] 6 2- ): (a) under UV/vis light; (b) under visible light >450 nm.…”

“…Electron-transfer sensitization was previously reported for titania containing up to 3% Pt(IV), Rh(III), or Au(III), either in the bulk or only at the surface. ,,, It has been shown that, in the case of PtCl 6 2- , the excited platinum complex first undergoes homolytic metal−chloride bond cleavage to yield a transient Pt(III) complex . Photochemical measurements indicated that the flat-band potential of this n-type semiconductor is shifted (to −0.30 V versus a normal hydrogen electrode, pH 7, compared to −0.53 V measured for pure titania).…”

Modification of Titanium Dioxide with Platinum Ions and Clusters: Application in Photocatalysis

“…Doping with Pt(IV) does not improve the photocatalytic activity of P25 under UV−visible light for RB degradation. The same result under UV−visible light was also obtained by Kisch et al ,, According to the literature, Degussa P25 catalytic properties could not also be improved by Pt(IV) doping 2 Degradation of RB (10 -4 M RB initial concentration) with pure or modified P25 titania (1 g/L photocatalyst) (surface modified and nonmodified with Pt salt (II), PtCl 4 2- ; Pt salt (IV), PtCl 6 2- ; Pt cluster, [Pt 3 (CO) 6 ] 6 2- ): (a) under UV/vis light; (b) under visible light >450 nm.…”

“…Electron-transfer sensitization was previously reported for titania containing up to 3% Pt(IV), Rh(III), or Au(III), either in the bulk or only at the surface. ,,, It has been shown that, in the case of PtCl 6 2- , the excited platinum complex first undergoes homolytic metal−chloride bond cleavage to yield a transient Pt(III) complex . Photochemical measurements indicated that the flat-band potential of this n-type semiconductor is shifted (to −0.30 V versus a normal hydrogen electrode, pH 7, compared to −0.53 V measured for pure titania).…”

Silver doped titanium dioxide nanoparticles as antimicrobial additives to dental polymers

“…The band gap shift was still towards the visible spectrum, but not to the same degree as the 6% doped Ag-TiO2. This finding was in contrast to other studies, which found the band gap shift continued towards the visible spectrum as the Ag loading of TiO2 continued to increase [14,15]. However, these studies manufactured Ag-TiO2 films using a hybrid sol-gel method, not ball milling, and so the findings cannot be directly compared.…”

Synthesis and photocatalytic activity of N-doped NaTaO3 compounds calcined at low temperature

“…close enough to the conduction band edge (shallow surface states) to induce electronic coupling, which may prevent charge recombination. So the photocatalytic activity of samples was enhanced [30]. Subsequently, the photocatalytic activity was decreased drastically with the further increasing of N content, which is a similar result as for N-doped TiO 2 or Ta 2 O 5 [31].…”

Modification of Titanium Dioxide with Platinum Ions and Clusters: Application in Photocatalysis

“…Doping with Pt(IV) does not improve the photocatalytic activity of P25 under UV−visible light for RB degradation. The same result under UV−visible light was also obtained by Kisch et al ,, According to the literature, Degussa P25 catalytic properties could not also be improved by Pt(IV) doping 2 Degradation of RB (10 -4 M RB initial concentration) with pure or modified P25 titania (1 g/L photocatalyst) (surface modified and nonmodified with Pt salt (II), PtCl 4 2- ; Pt salt (IV), PtCl 6 2- ; Pt cluster, [Pt 3 (CO) 6 ] 6 2- ): (a) under UV/vis light; (b) under visible light >450 nm.…”

“…Electron-transfer sensitization was previously reported for titania containing up to 3% Pt(IV), Rh(III), or Au(III), either in the bulk or only at the surface. ,,, It has been shown that, in the case of PtCl 6 2- , the excited platinum complex first undergoes homolytic metal−chloride bond cleavage to yield a transient Pt(III) complex . Photochemical measurements indicated that the flat-band potential of this n-type semiconductor is shifted (to −0.30 V versus a normal hydrogen electrode, pH 7, compared to −0.53 V measured for pure titania).…”

Silver doped titanium dioxide nanoparticles as antimicrobial additives to dental polymers

“…The band gap shift was still towards the visible spectrum, but not to the same degree as the 6% doped Ag-TiO2. This finding was in contrast to other studies, which found the band gap shift continued towards the visible spectrum as the Ag loading of TiO2 continued to increase [14,15]. However, these studies manufactured Ag-TiO2 films using a hybrid sol-gel method, not ball milling, and so the findings cannot be directly compared.…”

Synthesis and photocatalytic activity of N-doped NaTaO3 compounds calcined at low temperature

“…close enough to the conduction band edge (shallow surface states) to induce electronic coupling, which may prevent charge recombination. So the photocatalytic activity of samples was enhanced [30]. Subsequently, the photocatalytic activity was decreased drastically with the further increasing of N content, which is a similar result as for N-doped TiO 2 or Ta 2 O 5 [31].…”

Modification of Titanium Dioxide with Platinum Ions and Clusters: Application in Photocatalysis

“…Doping with Pt(IV) does not improve the photocatalytic activity of P25 under UV−visible light for RB degradation. The same result under UV−visible light was also obtained by Kisch et al ,, According to the literature, Degussa P25 catalytic properties could not also be improved by Pt(IV) doping 2 Degradation of RB (10 -4 M RB initial concentration) with pure or modified P25 titania (1 g/L photocatalyst) (surface modified and nonmodified with Pt salt (II), PtCl 4 2- ; Pt salt (IV), PtCl 6 2- ; Pt cluster, [Pt 3 (CO) 6 ] 6 2- ): (a) under UV/vis light; (b) under visible light >450 nm.…”

“…Electron-transfer sensitization was previously reported for titania containing up to 3% Pt(IV), Rh(III), or Au(III), either in the bulk or only at the surface. ,,, It has been shown that, in the case of PtCl 6 2- , the excited platinum complex first undergoes homolytic metal−chloride bond cleavage to yield a transient Pt(III) complex . Photochemical measurements indicated that the flat-band potential of this n-type semiconductor is shifted (to −0.30 V versus a normal hydrogen electrode, pH 7, compared to −0.53 V measured for pure titania).…”

Silver doped titanium dioxide nanoparticles as antimicrobial additives to dental polymers

“…The band gap shift was still towards the visible spectrum, but not to the same degree as the 6% doped Ag-TiO2. This finding was in contrast to other studies, which found the band gap shift continued towards the visible spectrum as the Ag loading of TiO2 continued to increase [14,15]. However, these studies manufactured Ag-TiO2 films using a hybrid sol-gel method, not ball milling, and so the findings cannot be directly compared.…”

Synthesis and photocatalytic activity of N-doped NaTaO3 compounds calcined at low temperature

“…close enough to the conduction band edge (shallow surface states) to induce electronic coupling, which may prevent charge recombination. So the photocatalytic activity of samples was enhanced [30]. Subsequently, the photocatalytic activity was decreased drastically with the further increasing of N content, which is a similar result as for N-doped TiO 2 or Ta 2 O 5 [31].…”