Water stable zinc-based metal organic framework and method of use

Patent metadata

Field	Value
Publication number	US-11767331-B2
Application number	US-201916394389-A
Country	US
Kind code	B2
Filing date	Apr 25, 2019
Priority date	Dec 18, 2018
Publication date	Sep 26, 2023
Grant date	Sep 26, 2023

Abstract

A zinc-based metal organic framework and method of making is described. The zinc-based metal organic framework is in the form of an interpenetrating diamondoid framework where each Zn 2+ ion center is linked with four other Zn 2+ ion centers in a distorted tetrahedral geometry. The linking occurs through diamine and dicarboxylic acid linkers. The zinc-based metal organic framework may be deposited on a transparent conducting film and used as a photoelectrode for photoelectrochemical water splitting.

First claim

The invention claimed is:

1. A zinc-based metal organic framework (Zn-MOF), comprising:
Zn 2+ ion centers,
wherein each Zn 2+ ion center is coordinated in a distorted tetrahedral geometry with a total of four linkers, the four linkers comprising:
two diamine linkers of N,N′-bis(pyridin-3-ylmethylene)cyclohexane-1,4-diamine, and
two dicarboxylic acid linkers of benzene-1,4-dicarboxylic acid,

wherein each Zn 2+ ion center is linked to each diamine linker through a N atom and linked to each dicarboxylic acid linker through a carboxylic acid group.

2. The Zn-MOF of claim 1 , wherein the Zn 2+ ion centers are linked together by the linkers in a diamondoid framework.

3. The Zn-MOF of claim 2 , which has a five-fold interpenetrating diamondoid framework.

4. The Zn-MOF of claim 1 , wherein the aromatic heterocyclic groups define planes that are substantially parallel with each other.

5. The Zn-MOF of claim 1 , wherein an average Zn—Zn spacing across either linker is in a range of 10-18 Å.

6. The Zn-MOF of claim 1 , wherein an average Zn bond angle is in a range of 105-115°.

7. The Zn-MOF of claim 1 , which has an ultraviolet visible absorption with an absorbance maximum in a range of 280-400 nm.

8. The Zn-MOF of claim 1 , which has a monoclinic crystal system with a C2/c space group.

9. The Zn-MOF of claim 1 , wherein a cyclohexane group of the diamine linker is in chair conformation.

10. A photoelectrochemical cell, comprising:
a photoelectrode comprising the Zn-MOF of claim 1 deposited on a metal oxide conducting substrate;
a counter electrode; and
an aqueous electrolyte solution in contact with both electrodes.

11. The photoelectrochemical cell of claim 10 , wherein the photoelectrode has a current density of 15-40 μA/cm 2 when the electrodes are subjected to a bias potential of 0.05-1.0 V and an illumination of 80-150 mW/cm 2 .

12. The photoelectrochemical cell of claim 10 , which does not comprise a sacrificial oxidant.

13. A method of photoelectrochemical water splitting, comprising:
irradiating the electrochemical cell of claim 10 with sunlight.

Assignees

• Univ King Fahd Pet & Minerals

Inventors

• Sohail Manzar
• Altaf Muhammad

Classifications

• C07F3/06 Primary

  Zinc compounds · CPC title

• B01J31/12

  containing organo-metallic compounds or metal hydrides · CPC title

• B01J35/004

  Operations & Transport · mapped topic

• C07F3/003 Primary

  without C-Metal linkages · CPC title

• C25B1/04

  by electrolysis of water · CPC title