Visible Light Activatable Photocatalyst

• US 20110028311A1
• Filed: 03/09/2009
• Published: 02/03/2011
• Est. Priority Date: 03/10/2008
• Status: Active Grant

• Current Assignee: Kastus Technologies Designated Activity Company
• Original Assignee: Dublin Institute of Technology
• Inventors: Etacheri, Vinodkumar, Colreavy, John, Pillai, Surresh C.
• Granted Patent: US 8,551,909 B2
• Time in Patent Office: Days
• US Class Current: 502/200
• CPC Class Codes: B01J 21/063 Titanium; Oxides or hydroxides thereof
• CPC Class Codes: B01J 23/745 Iron
• CPC Class Codes: B01J 27/12 Fluorides
• CPC Class Codes: B01J 27/16 containing oxygen , i.e. acids, anhydrides and their derivates with N, S, B or halogens without carriers or on carriers based on C, Si, Al or Zr; also salts of Si, Al and Zr
• CPC Class Codes: B01J 27/24 Nitrogen compounds
• CPC Class Codes: B01J 35/39 Photocatalytic properties
• CPC Class Codes: B01J 35/615 100-500 m2/g
• CPC Class Codes: B01J 35/647 2-50 nm
• CPC Class Codes: B01J 37/0215 Coating
• CPC Class Codes: B01J 37/346 of microwave energy
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01G 23/047 Titanium dioxide
• CPC Class Codes: C01G 23/053 Producing by wet processes, e.g. hydrolysing titanium salts
• CPC Class Codes: C01P 2002/52 containing elements as dopants
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2002/82 by IR- or Raman-data
• CPC Class Codes: C01P 2002/84 by UV- or VIS- data
• CPC Class Codes: C01P 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: C01P 2006/12 Surface area
• CPC Class Codes: C01P 2006/16 Pore diameter

Abstract

A visible light activatable mesoporous titanium dioxide photocatalyst having a surface area of from 100 m²/g to 400 m²/g. The photocatalyst may have a rate of decomposition greater than 0.005 min⁻¹. The photocatalyst may have a band gap width less than 2.95 eV. The photocatalyst may comprise undoped titanium dioxide or doped titanium dioxide. A hydrothermal process for synthesising a photocatalyst is also described.

Claims

1-53. -53. (canceled)

54. A visible light activatable mesoporous titanium dioxide photocatalyst having a surface area of from 100 m²/g to 400 m²/g.

55. The photocatalyst as claimed in claim 54 having a surface area of from 150 m²/g to 350 m²/g.

56. The photocatalyst as claimed in claim 54 having a surface area of from 200 m²/g to 300 m²/g.

57. The photocatalyst as claimed in claim 54 wherein the photocatalyst has a rate of decomposition greater than 0.005 min⁻

1, greater than 0.006 min<sup>−

1</sup>, greater than 0.007 min<sup>−

1</sup>.

58. The photocatalyst as claimed in claim 54 wherein the photocatalyst has a band gap width less than 2.95 eV, 2.9 eV or less, 2.82 eV or less.

59. The photocatalyst as claimed in claim 54 comprising undoped titanium dioxide.

60. The photocatalyst as claimed in claim 54 comprising doped titanium dioxide.

61. The photocatalyst as claimed in claim 60 wherein the dopant is selected from any one or more of the group comprising:

fluorine, iron, nitrogen, phosphor, and sulphur.

62. The photocatalyst as claimed in claim 60 wherein the dopant comprises between about 1:

0.0001 and about 1;

0.5 molar ratio titanium dioxide;

dopant, between about 1;

0.05 to about 1;

0.25 molar ratio titanium dioxide;

dopant.

63. The photocatalyst as claimed in claim 61 wherein the dopant is nitrogen.

64. The photocatalyst as claimed in claim 54 wherein the photocatalyst has a crystalline structure.

65. The photocatalyst as claimed in claim 64 wherein the photocatalyst has a crystallite size range of between about 5 nm to about 50 nm, between about 10 nm to about 30 nm.

68. The antimicrobial composition comprising a photocatalyst as claimed in claim 54.

69. The film or coating comprising a photocatalyst as claimed in claim 54.

70. The use of a photocatalyst as claimed in claim 54 in the preparation of an antimicrobial film or coating.

66. A photocatalyst comprising mesoporous titanium dioxide with a band gap width of 2.9 eV.

67. The photocatalyst as claimed in claim 66 comprising undoped titanium dioxide.

71. A process for forming a nanoporous crystalline material from an inorganic or organic precursor thereof comprising the steps of:

i) preparing a suspension from the inorganic or organic precursor; and

ii) utilising microwave irradiation, under non-pressurised conditions suitable to crystallise the material from the suspension, to crystallise the material from the suspension.

72. A use of microwave irradiation to crystallise a suspension of an inorganic or organic precursor of a nanoporous crystalline material under suitable conditions in a process for the formation a nanoporous crystalline material with a low energy band gap.