Nanoparticles, Nanosponges, Methods of Synthesis, and Methods of Use

Abstract

Disclosed are novel metallic nanoparticles coated with a thin protective carbon shell, and three-dimensional nano-metallic sponges; methods of preparation of the nanoparticles; and uses for these novel materials, including wood preservation, strengthening of polymer and fiber/polymer building materials, and catalysis.

What is claimed: 
     
         1 . Metallic nanosponges formed by a method comprising the steps of:
 (a) impregnating biological fibers with a solution of metal ions in an aqueous or non-aqueous solvent;   (b) removing solvent, while leaving at least some of the metal ions impregnated in the fibers; and   (c) heating the metal-ion-impregnated fibers in a non-oxidizing atmosphere or in a vacuum to a temperature or temperatures that initially carbonize at least some of the fibers, that then reduce at least some of the metal ions to metal particles in a zero oxidation state, and that then vaporize the carbon to produce metallic, highly porous nanosponges comprising zero-oxidation-state metal.   
     
     
         2 . The metallic nanosponges of  claim 1 , wherein the biological fibers are selected from the group consisting of cellulose, hemi-cellulose, lignin, cotton, rayon, flax, linen, jute, ramie, sisal, hemp, milkweed, straw, bagasse, hardwood, softwood, lepidopteran silk, hair, wool, spider silk, sinew, and catgut. 
     
     
         3 . The metallic nanosponges of  claim 1 , wherein the metal ions are selected from ions of the group consisting of Group HA metals (Be, Mg, Ca, Sr, Ba, Ra); Group IIIA metals or semi-metals (B, Al, Ga, In, Tl); Group IVA metals or semimetals (Si, Ge, Sn, Pb); Group VA metals or semi-metals (As, Sb, Bi); Group VIA semi-metals (Te, Po); Group IIIB metals (Sc, Y, La, Ac); Group IVB metals (Ti, Zr, Hf): Group VB metals (V, Nb, Ta); Group VIB metals (Cr, Mo, W); Group VIIB metals (Mn, Tc, Re); Group VIII metals (Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt); Group IB metals (Cu, Ag, Au); Group IIB metals (Zn, Cd, Hg); Lanthanides (Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu); and Actinides (Th, Pa, U, Np, Pu, Am). 
     
     
         4 . The metallic nanosponges of  claim 3 , wherein the metal ions are selected from ions of the group consisting of Cu, Ag, Ni, and Gd. 
     
     
         5 . The metallic nanosponges of  claim 3 , wherein the metal ions comprise copper ions. 
     
     
         6 . The metallic nanosponges of  claim 3 , wherein the metal ions comprise silver ions. 
     
     
         7 . A metallic nanosponge comprising a plurality of interconnecting, open metal tubes, wherein said tubes comprise porous walls, wherein most of said tubes are less than about 1 mm in diameter, wherein said porous walls comprise pores between about 10 nm and about 1 μm in diameter, and wherein the thickness of said walls is non-uniform, and is between 50 nm about and about 1 μm. 
     
     
         8 . A metallic nanosponge as recited in  claim 7 , wherein at least some of said tubes are 1 mm or longer. 
     
     
         9 . A metallic nanosponge as recited in  claim 7 , wherein at least some of said tubes are 1 cm or longer. 
     
     
         10 . A nanosponge as recited in  claim 7 , wherein said metal is selected from the group consisting of Group IIA metals (Be, Mg, Ca, Sr, Ba, Ra); Group IIIA metals or semi-metals (B, Al, Ga, In, Tl); Group IVA metals or semimetals (Si, Ge, Sn, Pb); Group VA metals or semi-metals (As, Sb, Bi); Group VIA semi-metals (Te, Po); Group IIIB metals (Sc, Y, La, Ac); Group IVB metals (Ti, Zr, Hf): Group VB metals (V, Nb, Ta); Group VIB metals (Cr, Mo, W); Group VIIB metals (Mn, Tc, Re); Group VIII metals (Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt); Group IB metals (Cu, Ag, Au); Group IIB metals (Zn, Cd, Hg); Lanthanides (Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu); and Actinides (Th, Pa, U, Np, Pu, Am). 
     
     
         11 . A nanosponge as recited in  claim 7 , wherein said metal comprises Cu. 
     
     
         12 . A nanosponge as recited in  claim 7 , wherein said metal comprises Ag. 
     
     
         13 . A nanosponge as recited in  claim 7 , wherein said metal comprises Pd. 
     
     
         14 . A nanosponge as recited in  claim 7 , wherein said metal comprises Pt. 
     
     
         15 . A nanosponge as recited in  claim 7 , wherein said metal comprises Ni. 
     
     
         16 . A nanosponge as recited in  claim 7 , wherein the diameter of most of said tubes is 500 μm or less. 
     
     
         17 . A nanosponge as recited in  claim 7 , wherein the diameter of most of said tubes is 50 μm or less. 
     
     
         18 . A nanosponge as recited in  claim 7 , wherein the diameter of most of said tubes is 5 μm or less. 
     
     
         19 . A nanosponge as recited in  claim 7 , wherein the diameter of most of said tubes is 500 nm or less. 
     
     
         20 . A nanosponge as recited in  claim 7 , wherein the diameter of most of said tubes is 100 nm or less.