Process for the preparation of titanium dioxide nanorods

Patent metadata

Field	Value
Publication number	US-9822017-B1
Application number	US-201615151987-A
Country	US
Kind code	B1
Filing date	May 11, 2016
Priority date	May 11, 2016
Publication date	Nov 21, 2017
Grant date	Nov 21, 2017

Abstract

The present invention relates to a process for preparing high aspect ratio titanium dioxide (TiO 2 ) nanorods using a one-pot hydrothermal technique. Reaction additives of oxalic acid and sodium hydroxide (NaOH) are used to promote the conversion of titanium dioxide precursors, preferably tetraisopropoxide (TTIP), into a one-dimensional TiO 2 morphology.

First claim

What is claimed is:

1. A process for the preparation of TiO 2 nanorods, comprising the reaction of a titanium dioxide precursor with oxalic acid and an alkali metal hydroxide.

2. The process of claim 1 , wherein the alkali metal hydroxide is NaOH.

3. The process of claim 1 , wherein the titanium dioxide precursor is selected from the group consisting of: titanium alkoxide, titanium halide, titanium tetrachloride, titanylsulphate, titanyl bis(acetylacetonate), titanium alkoxide, titanium tetramethoxide, titanium tetraethoxide, titanium tetra n-propoxide, titanium tetraisopropoxide (TTIP), titanium tetra n-butoxide and titanium tetra i-butoxide.

4. The process of claim 3 , wherein the titanium dioxide precursor is titanium tetraisopropoxide (TTIP).

5. The process of claim 1 , wherein the process is a hydrothermal one-pot synthesis.

6. The process according to claim 1 , wherein the nanorods have an aspect ratio in the range of about 30 to about 200.

7. The process of claim 1 , wherein the process comprises first reacting the oxalic acid with the titanium dioxide precursor to form a titanium oxalate solution in a reactor and subsequently adding the alkali metal hydroxide to the reactor, wherein the alkali metal hydroxide is NaOH.

8. The process of claim 7 , wherein during the addition of the NaOH the reactor is continuously stirred.

9. The process of claim 8 , wherein after the alkali metal hydroxide is added to the reactor, further comprising the step of heating of the reactor to a temperature in the range of about 100 to about 300° C.

10. The process of claim 9 , further comprising the step of cooling the product and rinsing the product with water and/or an acid.

11. The process of claim 10 , wherein the product was sequentially rinsed with acid and water.

12. The process of claim 10 , wherein the acid is selected from the group consisting of hydrochloric, nitric and sulfuric.

13. The process of claim 11 , further comprising the step of annealing the product at temperatures ranging from about 300 to about 1100° C.

14. The process of claim 13 , wherein the step of annealing the product is at a temperature in the range of 700° C. to 900° C. to form an anatase form of the TiO 2 nanorods.

15. The process of claim 13 , wherein the step of annealing the product is at a temperature of about 1100° C. to form a rutile form of the TiO 2 nanorods.

Assignees

• U S Army Edgewood Chemical And Biological Center
• Us Army

Inventors

• Zhang Dajie
• Delacy Brendan S
• Zander Zachary B

Classifications

• C01G23/053 Primary

  Producing by wet processes, e.g. hydrolysing titanium salts · CPC title

• C01P2004/16

  Nanowires or nanorods, i.e. solid nanofibres with two nearly equal dimensions between 1-100 nanometer · CPC title

• C01P2002/72

  by d-values or two theta-values, e.g. as X-ray diagram · CPC title

• C01P2004/03

  obtained by SEM · CPC title

• C01P2004/54

  Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension · CPC title