Metal oxide core-shell nanoparticles and applications thereof
In an aspect, a method of making a composite core-shell nanoparticle comprises forming a nanoparticle core comprising nickel oxide or iron oxide via thermal decomposition of a nickel complex or an iron complex; and forming an oxide shell over the core, the oxide shell comprising nickel, iron or a mixture thereof. In another aspect, a method of making composite nanoparticles comprises providing a mixture comprising nickel complex and iron complex; and thermally decomposing the nickel and iron complexes to provide the composite nanoparticles comprising (Ni,Fe)O x alloy. In yet another aspect, a composition comprises composite nanoparticles, the composite nanoparticles including a nickel oxide core and oxide shell, the oxide shell comprising a mixture of nickel and iron.
1. A composition comprising:
composite nanoparticles, the composite nanoparticles including a nickel oxide core and oxide shell, the oxide shell comprising a mixture of nickel and iron.
2. The composition of claim 1 , wherein the nickel oxide core is amorphous.
3. The composition of claim 1 , wherein the oxide shell has a thickness of 0.1-3 nm.
4. The composition of claim 1 , wherein the composite nanoparticles further comprise a nickel hydroxide phase.
5. The composition of claim 4 , wherein the nickel hydroxide phase comprises iron atoms.
6. The composition of claim 4 , wherein the nickel hydroxide phase is a primary phase of nickel atoms in the composite nanoparticles.
7. The composition of claim 4 , wherein the nickel hydroxide phase is a dominant phase of the composite nanoparticles.
8. The composition of claim 1 , wherein the composite nanoparticles are catalytically active for oxygen evolution reactions.
9. The composition of claim 1 , wherein a ratio of nickel to iron (Ni:Fe) in the oxide shell is 0.3 to 1.
10. The composition of claim 1 , wherein the oxide shell is functionalized with one or more ligand species.
11. The composition of claim 10 , wherein the one or more ligand species comprise one or more hydrophilic moieties.
12. The composition of claim 1 , wherein the oxide shell is amorphous.
13. The composition of claim 1 , wherein the iron is present as γ-Fe 2 O 3 .
14. The composition of claim 1 , wherein the composite nanoparticles are substantially spherical.
15. An electrode comprising:
a substrate; and
a coating of composite nanoparticles on the substrate, the composite nanoparticles including a nickel oxide core and oxide shell, the oxide shell comprising a mixture of nickel and iron.
16. The electrode of claim 15 , wherein the substrate is a transition metal or transition metal alloy.
17. The electrode of claim 15 , wherein the substrate comprises carbon nanoparticles.
18. The electrode of claim 15 , wherein the composite nanoparticles further comprise a nickel hydroxide phase.
19. The electrode of claim 18 , wherein the nickel hydroxide phase is a primary phase of nickel atoms in the composite nanoparticles.
20. The electrode of claim 18 , wherein the nickel hydroxide phase is a dominant phase of the composite nanoparticles.