Method for preparation of nanoceria supported atomic noble metal catalysts and the application of platinum single atom catalysts for direct methane conversion
Described are methods for converting methane to olefins, aromatics, or a combination thereof using a single atom catalyst comprising CeO 2 nanoparticles impregnated with individual atoms of noble metals including Pt, Pd, Rh, Ru, Ag, Au, Ir, or a combination thereof. These single atom catalysts of the present invention are heated with methane to form olefins and aromatics.
1. A single atom catalyst comprising:
CeO 2 nanoparticles impregnated with individual noble metal atoms; and
wherein an atomic ratio of a Ce 4+ oxidation state to a Ce 3+ oxidation state is 1.188.
2. The single atom catalyst of claim 1 wherein the noble metal atoms are selected from the group consisting of Pt, Pd, Rh, Ru, Ag, Au, Ir, and a combination thereof.
3. The single atom catalyst of claim 2 , wherein the noble metal atoms consist of Pt.
4. The single atom catalyst of claim 3 , wherein the platinum is present only in a Pt 2+ oxidation state.
5. The single atom catalyst of claim 3 , wherein a content of Pt is from about 0.42 wt % to about 0.50 wt % of a total weight of the single atom catalyst.
6. The single atom catalyst of claim 3 , wherein the Pt is in an oxidized form.
7. The single atom catalyst of claim 1 , wherein the single atom catalyst has a particle size of from about 15 nm to about 40 nm.
8. The single atom catalyst of claim 1 , comprising a specific surface area in the range of 5 m 2 /g to 40 m 2 /g.
9. The single atom catalyst of claim 1 , comprising binding energies in a range of 50 eV to 90 eV.
10. A single atom catalyst comprising:
CeO 2 nanoparticles impregnated with individual platinum atoms; and
binding energies in a range of 50 eV to 90 eV; and
wherein an atomic ratio of a Ce 4+ oxidation state to a Ce 3+ oxidation state is 1.188.