Gold loaded TiO2 nanotube-multiwalled carbon nanotube composites as active photocatalysts for cyclohexane oxidation

• US 9,452,418 B2
• Filed: 01/23/2015
• Issued: 09/27/2016
• Est. Priority Date: 01/23/2015
• Status: Expired due to Fees

• Current Assignee: Umm Al-Qura University
• Original Assignee: Umm Al-Qura University
• Inventors: Saleh, Saleh Abdel-Mgeed Ahmed, Abdalla, Mohamed Mokhtar Mohamed, Khairou, Khalid Soliman Khalil
• Primary Examiner(s): WITHERSPOON, SIKARL A
• Application Number:
  US14/419,103
• Publication Number:
  US 20160214087A1
• Time in Patent Office: 613 Days
• Field of Search: 568/342
• US Class Current: 1/1
• CPC Class Codes: B01J 21/063 Titanium; Oxides or hydroxides thereof
• CPC Class Codes: B01J 21/185 Carbon nanotubes carbon nanotubes per se C01B32/15
• CPC Class Codes: B01J 23/48 Silver or gold
• CPC Class Codes: B01J 23/52 Gold
• 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 35/40 characterised by dimensions, e.g. grain size in a colloidal state B01J35/23; crystallite size B01J35/77
• CPC Class Codes: B01J 35/50 characterised by their shape or configuration
• CPC Class Codes: B01J 35/613 10-100 m2/g
• CPC Class Codes: B01J 35/615 100-500 m2/g
• CPC Class Codes: B01J 35/633 less than 0.5 ml/g
• CPC Class Codes: B01J 37/0207 Pretreatment of the support
• CPC Class Codes: B01J 37/0215 Coating
• CPC Class Codes: B01J 37/0242 Coating followed by impregnation
• CPC Class Codes: B01J 37/16 Reducing
• CPC Class Codes: B01J 37/343 of ultrasonic wave energy
• CPC Class Codes: C07C 2601/14 The ring being saturated
• CPC Class Codes: C07C 29/48 by oxidation reactions with formation of hydroxy groups
• CPC Class Codes: C07C 35/08 : containing a six-membered rings
• CPC Class Codes: C07C 45/28 : of CHx-moieties
• CPC Class Codes: C07C 45/294 : with hydrogen peroxide
• CPC Class Codes: C07C 49/403 : of a six-membered ring

Abstract

A gold/titanium nanotube-multiwalled carbon nanotube composite (Au/TNT-MWCNT) is presented. The gold composition comprises at least 3% weight of the nanotube composite based on the total weight of the nanotube composite and the gold composition is located in at least one of the wall of the titanium nanotube and the wall of the multiwalled carbon nanotube. Photocatalytic oxidation of neat cyclohexane (CHA) with H₂O₂ as an oxidant was carried out. Au/TNT-MWCNT catalysts promoted partial CHA oxidation with high conversion (6-7.5%) and selectivity (60-75%) to cyclohexanone.

Claims

1. A method for oxidation of cyclohexane, comprising:

reacting cyclohexane in a photocatalytic oxidation reaction in the presence of a solution of H₂O₂ and a gold titanium nanotube-multiwalled carbon nanotube composite, comprising;

30-40 weight % multi-walled carbon nanotubes and 60-70% weight % titanium nanotubes, each based on the total weight of the titanium nanotubes and the multiwalled carbon nanotubes; and

2-4 weight % of Au based on the total weight of the nanotube composite, wherein the Au is located in at least one wall of the titanium nanotube and wall of the multiwalled carbon nanotube.

2. The method of claim 1, wherein 0.02-0.10 g of the nanotube composite is employed per 10 mmol of cyclohexane.

3. The method of claim 1, wherein the solution of H₂O₂ has a concentration in the range of 10-40%.

4. The method of claim 1, wherein the nanotube composite has an average particle diameter of 10-20 nm.

5. The method of claim 1, wherein the nanotube composite has a surface area of 50-500 m²/g.

6. The method of claim 1, wherein the nanotube composite has a pore volume of 0.180-0.199 cm³/g.

7. The method of claim 1, wherein the nanotube composite has a spindle shape.

8. The method of claim 1, wherein the nanotube composite has 3-3.5 weight % of Au based on the total weight of the nanotube composite.

9. The method of claim 1, wherein the nanotube composite comprises 30% by weight of the multi-walled carbon nanotube and 70% by weight of the titanium nanotube, each based on the total weight of the titanium nanotubes and the multiwalled carbon nanotubes.