CERIUM DIOXIDE NANOPARTICLES AND METHODS FOR THEIR PREPARATION AND USE

2 . A method of making one or more nanoparticles, the method comprising:

contacting Ce(NO 3 ) 3 and a base at a pressure and temperature to form a mixture comprising the one or more nanoparticles.

3 . The method of claim 2 , further comprising converting the mixture into a composition comprising one or more porous CeO 2 nanoparticles.

4 . The method of claim 2 , wherein contacting comprises contacting with NaOH, KOH, or combinations thereof.

5 . (canceled)

6 . The method of claim 2 , wherein contacting comprises contacting at a ratio of Ce(NO 3 ) 3 to base of about 1:80 to about 1:200.

(canceled)

8 . The method of claim 2 , wherein the contacting comprises contacting at a pressure of about 1.0 atmospheres to about 1.5 atmospheres.

9 . The method of claim 2 , wherein the contacting comprises contacting at a temperature of about 100° C.

10 .- 12 . (canceled)

13 . The method of claim 2 , wherein contacting results in forming one or more nanoparticles comprising CeO 2 and Ce(OH) 3 .

14 . The method of claim 2 , wherein contacting results in forming one or more nanoparticles having an average length of about 40 nm to about 80 nm and an average diameter of about 5 nm to about 8 nm.

15 .- 16 . (canceled)

17 . The method of claim 2 , wherein contacting result in forming one or more non-porous nanoparticles.

18 . The method of claim 2 , further comprising:

washing the mixture to remove excess base after contacting Ce(NO 3 ) 3 and the base.

19 . (canceled)

20 . The method of claim 18 , wherein the washing results in the mixture having a neutral pH value.

21 .- 24 . (canceled)

25 . The method of claim 3 , converting the mixture comprises dehydration.

26 . The method of claim 25 , wherein dehydrating comprises dehydrating by a hydrothermal method.

27 .- 31 . (canceled)

32 . The method of claim 3 , wherein converting the mixture comprises calcining.

33 . The method of claim 32 , wherein calcining comprises calcining at a temperature of about 200° C. to about 600° C.

34 .- 37 . (canceled)

38 . The method of claim 3 , wherein the converting the mixture comprises forming a mixture including one or more porous CeO 2 nanoparticles have having an oxygen vacancy concentration that is larger than the oxygen vacancy concentration of nonporous CeO 2 nanoparticles.

39 . The method of claim 3 , wherein converting the mixture comprises forming a mixture including one or more porous CeO 2 nanoparticles have having a specific surface area of at least about 95 m 2 /g.

40 .- 41 . (canceled)

42 . The method of claim 3 , wherein the converting the mixture comprises forming a mixture including one or more porous CeO 2 nanoparticles have having an oxygen storage capacity of at least about 700 μmol O 2 /g.

43 . The method of claim 3 , wherein the converting the mixture comprises forming a mixture including one or more porous CeO 2 nanoparticles have having an oxygen storage capacity of about 700 μmol O 2 /g to about 900 μmol O 2 /g.

44 .- 45 . (canceled)

46 . The method of claim 3 , wherein converting the mixture comprises forming a mixture including one or more porous CeO 2 nanoparticles having a specific surface Ce 3+ ratio of at least about 9%.

47 .- 49 . (canceled)

50 . The method of claim 3 , further comprising dispersing at least one active component in the composition.

51 . The method of claim 50 , wherein dispersing comprises dispersing-at least one noble metal, at least one metal oxide, at least one bi-metal, at least one triple-metal, or combinations thereof.

52 .- 57 . (canceled)

58 . At least one A porous CeO 2 nanoparticle having one or more of comprising one or more of:

an oxygen vacancy concentration exceeding the oxygen vacancy concentration of a nonporous CeO 2 nanoparticle;

a specific surface area of at least about 95 m 2 /g;

an oxygen storage capacity of at least about 700 μmol O 2 /g; and

a specific surface Ce 3+ ratio of at least about 9%.

59 .- 60 (canceled)

61 . The porous CeO 2 nanoparticle of claim 58 , wherein the at least one porous CeO 2 nanoparticle has a specific surface area of about 95 m 2 /g to about 150 m 2 /g.

62 .- 63 . (canceled)

64 . The at least one porous CeO 2 nanoparticle of claim 58 , wherein the at least one porous CeO 2 nanoparticle has an oxygen storage capacity of about 700 μmol O 2 /g to about 900 μmol O 2 /g.

65 .- 67 . (canceled)

68 . The porous CeO 2 nanoparticle of claim 58 , wherein the porous CeO 2 nanoparticle has a specific surface Ce 3+ ratio of about 9% to about 33%.

69 . The porous CeO 2 nanoparticle of claim 58 , wherein the porous CeO 2 nanoparticle has a specific surface Ce 3+ ratio of about 30.8%.

70 . (canceled)

71 . The porous CeO 2 nanoparticle of claim 58 , further comprising at least one active component.

72 . The porous CeO 2 nanoparticle of claim 71 , wherein the at least one active component comprises at least one noble metal, at least one metal oxide, at least one bi-metal, at least one triple-metal, or combinations thereof

73 . The porous CeO 2 nanoparticle of claim 72 , wherein the at least one noble metal comprises ruthenium, rhodium, palladium, osmium, iridium, platinum, gold, mercury, rhenium, silver, copper, or combinations thereof

74 . The porous CeO 2 nanoparticle of claim 72 , wherein the at least one metal oxide comprises CuO, NiO, Co 3 O 4 , or combinations thereof.

75 . The porous CeO 2 nanoparticle of claim 72 , wherein the at least one bi-metal comprises PtPd, AuPd, or combinations thereof.

76 . The porous CeO 2 nanoparticle of claim 72 , wherein the at least one bi-metal comprises two metals selected from Ni, Co, Au, Ag, Cu, Fe, Pt, Pd, Rh, Ru, and Ir.

77 . The porous CeO 2 nanoparticle of claim 72 , wherein the at least one triple-metal comprises CoNiPt, CuPdAu, or combinations thereof

78 . The porous CeO 2 nanoparticle of claim 72 , wherein the at least one triple-metal comprises three metals selected from Ni, Co, Au, Ag, Cu, Fe, Pt, Pd, Rh, Ru, and Ir.

79 .- 162 (canceled)