Nanocrystalline heterojunction materials

• US 6,592,842 B2
• Filed: 05/16/2001
• Issued: 07/15/2003
• Est. Priority Date: 10/01/1999
• Status: Expired due to Fees

• Current Assignee: Battelle Memorial Institute
• Original Assignee: Battelle Memorial Institute
• Inventors: Gao, Yufei, Su, Yali, Heald, Steve M., Elder, Scott H.
• Primary Examiner(s): Silverman, Stanley S.
• Assistant Examiner(s): Nguyen, Cam N.
• Application Number:
  US09/859,799
• Publication Number:
  US 20020071970A1
• Time in Patent Office: 790 Days
• Field of Search: 423/598, 423/610, 502/309, 502/350, 502/351
• US Class Current: 423/610
• CPC Class Codes: B01J 21/063 Titanium; Oxides or hydroxides thereof
• CPC Class Codes: B01J 35/30 characterised by their physical properties
• CPC Class Codes: B01J 35/39 Photocatalytic properties
• CPC Class Codes: B01J 35/40 characterised by dimensions, e.g. grain size in a colloidal state B01J35/23; crystallite size B01J35/77

Abstract

Mesoporous nanocrystalline titanium dioxide heterojunction materials are disclosed. In one disclosed embodiment, materials comprising a core of titanium dioxide and a shell of a molybdenum oxide exhibit a decrease in their photoadsorption energy as the size of the titanium dioxide core decreases.

Claims

1. A heterojunction material, comprising:

a nanocrystalline titanium dioxide phase; and

a second metal oxide phase, wherein the nanocrystalline titanium dioxide phase is chemically bonded to the second metal oxide phase through a heterojunction formed at an interface between the nanocrystalline titanium dioxide phase and the second metal oxide phase.

2. The heterojunction material of claim 1, wherein the nanocrystalline titanium dioxide phase is anatase.

3. The heterojunction material of claim 1, wherein the material exhibits a photoabsorption energy lower than 3.2 eV.

4. The heterojunction material of claim 1, wherein the second metal oxide phase forms a shell around a core comprising the nanocrystalline titanium dioxide phase, the heterojunction formed at the interface between the shell and the core.

5. The heterojunction material of claim 4, wherein the shell comprises from less than a complete monolayer to one or more monolayers of the second metal oxide.

6. The heterojunction material of claim 4, wherein the shell is molybdenum oxide and the core is nanocrystalline anatase.

7. The heterojunction material of claim 6, wherein the molybdenum oxide phase has a structure substantially similar to bulk α

-MoO₃.

8. The heterojunction material of claim 6, wherein Mo L₃-edge data for the material has a low-energy peak of greater intensity than a high-energy peak.

9. The heterojunction material of claim 6, wherein a Raman scattering signal corresponding to the M═

symmetric stretching mode is not influenced by hydration.

10. The heterojunction material of claim 1, wherein the metal oxide comprises a metal selected from the group consisting of V, W, Nb, Mo, Al and combinations thereof.

11. The heterojunction material of claim 10, wherein the metal is V, Al, W or Nb.