Multifunctional nanomaterials and methods of photothermal heating and catalysis using the same
The present invention is directed to multifunctional nanomaterials for photothermal heating and catalytic applications. The present invention discloses a method of photothermally heating a solution. The present method also discloses a method of catalyzing a reaction. Both methods require a step of exposing a solution to at least one wavelength of the electromagnetic spectrum. A gold-iron oxide nanomaterial comprising an iron oxide substrate and discrete gold particles deposited on the substrate is also disclosed.
1. A method of photothermally heating a solution, the method comprising
exposing the solution to at least one wavelength of light of the electromagnetic spectrum,
wherein the solution contains gold-iron oxide nanomaterials comprising an iron oxide substrate and discrete gold particles deposited on the iron oxide substrate,
wherein the iron oxide substrate comprises a nanotube, a nanoring, or mixtures thereof.
2. The method of claim 1 , wherein the at least one wavelength of light is in the visible light spectrum.
3. The method of claim 1 , wherein the at least one wavelength of light is in the infrared spectrum.
4. The method of claim 1 , wherein the at least one wavelength of light is in the ultraviolet spectrum.
5. The method of claim 1 , wherein the iron oxide substrate is a nanotube.
6. The method of claim 1 , wherein the iron oxide substrate is a nanoring.
7. The method of claim 1 , wherein the iron oxide substrate has an average outer diameter of from 5 nm to 500 nm.
8. The method of claim 1 , wherein the iron oxide substrate has an inner diameter of from 5 nm to 500 nm.
9. The method of claim 1 , wherein the iron oxide substrate has an average length of from 10 nm to 500 nm.
10. The method of claim 1 , wherein the iron oxide is Fe 2 O 3 .
11. The method of claim 1 , wherein the iron oxide has a maghemite crystal phase.
12. The method of claim 1 , wherein the iron oxide has a hematite crystal phase.
13. The method of claim 1 , wherein the gold particles have an average diameter of from 5 nm to 100 nm.
14. The method of claim 1 , wherein the gold particles are not agglomerated on the iron oxide substrate.
15. The method of claim 1 , wherein the gold-iron oxide nanomaterial has an average surface area of from 5 m 2 /g to 200 m 2 /g.
16. The method of claim 1 , wherein the iron oxide substrate of the gold-iron oxide nanomaterial has an average surface area of from 5 m 2 /g to 200 m 2 /g.
17. The method of claim 1 , wherein the gold particles of the gold-iron oxide nanomaterial have an average surface area of from 0.0001 m 2 /g to 5 m 2 /g.
18. The method of claim 1 , wherein the iron to gold atomic ratio of the gold-iron oxide nanomaterial is from 3 to 200.
19. The method of claim 1 , wherein the at least one wavelength is in a range of from 400 nm to 750 nm.
20. The method of claim 1 , wherein the solution is exposed for at least 3 minutes and the bulk temperature of the solution increases by at least 10° C.
21. The method of claim 1 , wherein if the solution is exposed to a wavelength of from 500 to 600 nm for at least 5 minutes, the bulk temperature of the solution increases by at least 10° C.
22. The method of claim 1 , wherein the solution is an aqueous solution.
23. The method of claim 1 , wherein the solution further comprises at least one reactant, reagent, or any combination thereof.
24. The method of claim 23 , wherein the method further comprises a method of catalyzing a reaction.