CuO - TiO2 NANOCOMPOSITE PHOTOCATALYST FOR HYDROGEN PRODUCTION, PROCESS FOR THE PREPARATION THEREOF

• US 20160045908A1
• Filed: 08/14/2014
• Published: 02/18/2016
• Est. Priority Date: 08/14/2014
• Status: Active Grant

• Current Assignee: Council of Scientific & Industrial Research
• Original Assignee: Council of Scientific & Industrial Research
• Inventors: Subrahmanyam, Machiraju, Kumari, Valluri Durga, Srinivas, Basavaraju, Sadanandam, Gullapelli, Shankar, Muthukonda Venkatakrish Nan, Sundar, Bethanabhatla Syama, Kumari, Murikinati Mamatha, Kumar, Dharani Praveen
• Granted Patent: US 9,776,162 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B01J 19/123 Ultraviolet light
• CPC Class Codes: B01J 21/063 Titanium; Oxides or hydroxides thereof
• CPC Class Codes: B01J 23/72 Copper
• CPC Class Codes: B01J 35/23 in a colloidal state
• CPC Class Codes: B01J 35/30 characterised by their physical properties
• CPC Class Codes: B01J 35/39 Photocatalytic properties
• CPC Class Codes: B01J 35/393 Metal or metal oxide crystallite size
• CPC Class Codes: B01J 37/0207 Pretreatment of the support
• CPC Class Codes: B01J 37/031 Precipitation
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: B82Y 40/00 Manufacture or treatment of nanostructures
• CPC Class Codes: C01B 3/042 Decomposition of water
• CPC Class Codes: Y02E 60/36 Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
• CPC Class Codes: Y10S 977/762 Nanowire or quantum wire, i.e. axially elongated structure having two dimensions of 100 nm or less
• CPC Class Codes: Y10S 977/811 Of specified metal oxide composition, e.g. conducting or semiconducting compositions such as ITO, ZnOx
• CPC Class Codes: Y10S 977/896 Chemical synthesis, e.g. chemical bonding or breaking

Abstract

The present investigation is development of the TiO₂ nanotubes concept of preparation of and their composite with fine dispersion of copper. The inventions also relates to identify a method for optimum amount of photocatalyst required for efficient and maximum hydrogen production reported than earlier (H₂=99,823 μmol·h⁻¹·g⁻¹ catalyst) from glycerol-water mixtures under solar light irradiation. A method is disclosed to produce CuO/TiO₂ nanotubes with high sustainability and recyclable activity for hydrogen production.

Claims

1. CuO—

TiO₂ nanocomposite photocatalyst which comprises of TiO₂ nanotubes in the range of 98-99.9 wt % and CuO in the range of 0.1 to 2 wt %.

2. CuO—

TiO₂ nanocomposite photocatalyst as claimed in claim 1, wherein TiO₂ nanotube composed of bicrystalline anatase-rutile phase with tube length 300 to 400 nm and diameter 8-12 nm.

3. CuO—

TiO₂ nanocomposite photocatalyst as claimed in claim 1, wherein CuO is deposited on TiO₂ nanotubes surface in the form of quantum dots.

4. CuO—

TiO₂ nanocomposite photocatalyst as claimed in claim 3, wherein size of CuO quantum dots is less than 10 nm.

5. A method for the preparation of CuO—

TiO₂ nanocomposite photocatalyst as claimed in claim 1, wherein the said process comprising the steps of;

a) dispersing TiO₂ μ

m-sized particles (TMP) into NaOH aqueous solution under magnetic stirring at temperature ranging between 25 to 35°

C. for a period ranging between 0.5 to 2 h to obtain homogeneous suspension;

b) heating homogeneous suspension as obtained in step (a) into an autoclave for a period ranging between 6 to 72 h at temperature ranging between 120 to 150°

C. to obtain precipitate of TiO₂ nanotube followed by washing with water, dilute HCl and ethanol in steps subsequently drying the precipitate at temperature ranging between 60 to 100°

C. for a period ranging between 8 to 24 h then calcining TiO₂ nanotube at temperature ranging between 300 to 400°

C. for a period ranging 2 to 7 h to obtain calcined TiO₂ nanotube;

c) dispersing calcined TiO₂ nanotube as obtained in step (b) into Cu(NO₃)₂.3H₂O aqueous solution followed by evaporating excess water to dryness with slow heating and constant magnetic stirring subsequently drying at 100-150°

C. for 8 to 16 h and calcining at 300-400°

C. for 3-6 h range to obtain CuO—

TiO₂ nanocomposite photocatalyst.

6. The method as claimed in claim 5, wherein mol ratio of TiO₂ nanotube and Cu(NO₃)₂.3H₂O in step (c) used is in the range of 1.5 wt %.

7. A process for H₂ production from glycerol-water mixture using CuO—

TiO₂ nanocomposite photocatalyst as claimed in claim 1, wherein the said process comprises stirring CuO—

TiO₂ nanocomposite photocatalyst with glycerol-water mixture (3 to 7 vol. %) for a period ranging between 0.5 to 2 h under dark condition at temperature ranging between 28-34°

C. followed by evacuation and purged with N₂ gas subsequently stirring the solution under solar light for a period ranging between 1 to 4 h to obtain H₂ gas.

8. The process as claimed in claim 7, wherein H₂ production rate is in the range of 82,746 to 99,823 μ

mol·

h<sup>−

1</sup>·

g<sup>−

1</sup> catalyst.