Chemochromic nanoparticles, method for manufacturing the same, and hydrogen sensor comprising the same

Abstract

Disclosed are a chemochromic nanoparticle, a method for manufacturing the chemochromic nanoparticle, and a hydrogen sensor comprising the chemochromic nanoparticle. In particular, the chemochromic nanoparticle has a core-shell structure such that the chemochromic nanoparticle and comprises a core comprising a hydrated or non-hydrated transition metal oxide; and a shell comprising a transition metal catalyst.

What is claimed is: 
     
         1 . A chemochromic nanoparticle, comprising:
 a core comprising a transition metal oxide; and   a shell comprising a metal catalyst partially coated on a surface of the core.   
     
     
         2 . The chemochromic nanoparticle according to  claim 1 , wherein the transition metal oxide comprises a non-hydrated transition metal oxide which is not doped with water molecules or a hydrated transition metal oxide which is doped with water molecules. 
     
     
         3 . The chemochromic nanoparticle according to  claim 1 , wherein the transition metal oxide comprises a metal oxide of one or two or more selected from the group consisting of SnO 2 , TiO 2 , ZnO, VO 2 , In 2 O 3 , NiO, MoO 3 , SrTiO 3 , Fe 2 O 3 , WO 3 , and CuO. 
     
     
         4 . The chemochromic nanoparticle according to  claim 1 , wherein the transition metal oxide comprises tungsten oxide (WO 3 ). 
     
     
         5 . The chemochromic nanoparticle according to  claim 1 , wherein an average particle size of the transition metal oxide ranges from about 1 to about 200 nm. 
     
     
         6 . The chemochromic nanoparticle according to  claim 1 , wherein the metal catalyst comprises one metal or particles of two or more metals selected from the group consisting of Pd, Pt, Ru, Mg, Au, and Ir. 
     
     
         7 . The chemochromic nanoparticle according to  claim 1 , wherein the metal catalyst comprises one or two or more metal compounds selected from the group consisting of palladium chloride (PdCl 2 ), palladium ammonium nitrate (Pd(NH 3 ) 2 (NO 3 )), palladium bromide (PdBr 2 ), palladium oxide hydrate (PdOH 2 O), palladium sulfate (PdSO 4 ), palladium nitrate (Pd(NO 3 ) 2 ), palladium acetylacetate ((CH 3 COCH═C(O − )CH 3 ) 3 Pd), platinum chloride (PtCl 2 , PtCl 4 ), platinum bromide (PtBr 2 ), platinum oxide (PtO 2x H 2 O), platinum sulfide (PtS 2 ), ruthenium oxide hydrate (RuO 2x H 2 O), ruthenium acetylacetate [(CH 3 COCH═C(O − )CH 3 ) 3 Ru], ruthenium bromide (RuBr 3 ), iridium chloride (IrCl 3 ), iridium acetylacetate ((CH 3 COCH═C(O − )CH 3 ) 3 Ir), and iridium chloride hydrate (IrCl 4x H 2 O). 
     
     
         8 . The chemochromic nanoparticle according to  claim 1 , wherein the metal catalyst comprises palladium chloride (PdCl 2 ). 
     
     
         9 . The chemochromic nanoparticle according to  claim 1 , wherein the shell comprising the metal catalyst is formed using a solution synthesis method using UV irradiation. 
     
     
         10 . The chemochromic nanoparticle according to  claim 1 , wherein a thickness of the shell comprising the metal catalyst ranges from about 0.1 to about 50 nm. 
     
     
         11 . The chemochromic nanoparticle according to  claim 1 , wherein the shell is partially coated on the surface of the core in a dot form. 
     
     
         12 . The chemochromic nanoparticle according to  claim 1 , wherein the chemochromic nanoparticle comprises: the cored in an amount of about 80 to 90 wt % and the shell in an amount of about 10 to 20 wt % based on the total weight of the chemochromic nanoparticle. 
     
     
         13 . A method for manufacturing a chemochromic nanoparticle, the method comprising:
 preparing a hydrated or non-hydrated transition metal oxide;   preparing a metal catalyst solution by dissolving a metal catalyst precursor and a polymer compound in an organic solvent;   preparing a mixed solution by adding the hydrated or non-hydrated transition metal oxide to the metal catalyst solution;   manufacturing the chemochromic nanoparticle with a core-shell structure by irradiating UV light to the mixed solution; and   obtaining the chemochromic nanoparticle by filtering the mixed solution,   wherein the chemochromic nanoparticle is formed in a core-shell structure.   
     
     
         14 . The method according to  claim 13 , wherein the polymer compound comprises one or a mixture of two or more selected from the group consisting of polyurethane, polyetherurethane, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, polymethylmethacrylate (PMMA), polymethylacrylate (PMA), polyacrylic copolymers, polyvinylacetate (PVAc), polyvinylacetate copolymers, polyvinylalcohol (PVA), polystyrene, polystyrene copolymers, polyethyleneoxide (PEO), polypropyleneoxide (PPO), polyethyleneoxide copolymers, polycarbonate (PC), polyvinylchloride (PVC), polycaprolactone, polyvinylpyrrolidone (PVP), polyvinylfluoride, polyvinylidene fluoride copolymers, and polyamide. 
     
     
         15 . The method according to  claim 13 , wherein the organic solvent comprises an alcohol based solvent. 
     
     
         16 . The method according to  claim 13 , wherein the irradiating of the UV light is performed by exposure to the UV light having a wavelength of about 365 nm, at room temperature for about 2 to 3 minutes and an output of the UV light is of about 1000 W. 
     
     
         17 . A hydrogen sensor comprising:
 a chemochromic nanoparticle of  claim 1 ; and   at least one member selectively selected from the group consisting of a polymer, aerogel, and a solvent.   
     
     
         18 . A method for preparing a hydrated or non-hydrated tungsten oxide, the method comprising:
 preparing an aqueous ammonium paratungstate solution;   adding hydrochloric acid to the aqueous ammonium paratungstate solution and stirring the mixture to prepare an aqueous tungstic acid solution;   adding hydrogen peroxide to the aqueous tungstic acid solution to prepare an aqueous peroxo-polytungstic acid solution;   injecting the aqueous peroxo-polytungstic acid solution into an autoclave and performing primary heat treatment;   precipitating a hydrated tungsten oxide by air-cooling the autoclave after a reaction is terminated; and   obtaining the tungsten oxide.   
     
     
         19 . The method according to  claim 18 , wherein the primary heat treatment is performed at a temperature of about 160° C. in the autoclave and an internal pressure in the autoclave is maintained at about 35 to 50 bar. 
     
     
         20 . The method according to  claim 18 , the method further comprising:
 re-injecting the obtained tungsten oxide into the autoclave; and   performing a secondary heat treatment to the tungsten oxide in the autoclave at a temperature of about 500° C.