Electrode having sintered gold nanostructure

Abstract

A synthetic methodology for robust, nanostructured films of cobalt oxide over metal evaporated gold or similar material layer of, e.g., 50 nm, directly onto glass or other substrates via aerosol assisted chemical vapor deposition (AACVD). This approach allows film growth rates in the range of, e.g., 0.8 nm/s, using a commercially available precursor, which is ~10-fold the rate of electrochemical synthetic routes. Thus, 250 nm thick cobalt oxide films may be generated in only 5 minutes of deposition time. The water oxidation reaction for such films may start at ~0.6 V vs Ag/AgCl with current density of 10 mA/cm 2 and is achieved at ~0.75 V corresponding to an overpotential of 484 mV. This current density is further increased to 60 mA/cm 2 at ~1.5 V (vs Ag/AgCl). Electrochemically active surface area (ECSA) calculations indicate that the synergy between a Au-film, acting as electron sink, and the cobalt oxide film(s), acting as catalytic layer(s), are more pronounced than the surface area effects.

1 - 2 . (canceled) 
     
     
         3 . The electrode of  claim 18 , wherein the electron sink material comprises at least 95 wt.%, relative to the total electron sink coating weight, of Au. 
     
     
         4 . The electrode of  claim 18 , wherein the layer comprising the sintered Au nanostructure has a thickness in the range of 30 to 70 nm. 
     
     
         5 - 6 . (canceled) 
     
     
         7 . The electrode of  claim 18 , wherein the cobalt solution comprises cobalt(III) acetylacetonate, cobalt(II) acetylacetonate, cobalt(II) carbonate, cobalt(II) acetate, cobalt naphthenate, cobalt(II) phthalocyanine, cobalt(II) 2-ethylhexanoate, dicarbonyl-cyclopentadienyl cobalt(I), cobalt(II) oxalate, cobalt(II) oxo pivalate, cobalt(II) ethyl/butyl phosphonate, cobalt(II) nitrate, tris(ethylenediamine)cobalt(III) chloride, dichloro-bis(ethylenediamine) cobalt(III) halide, monocobalt edetate, bis(cyclopentadienyl) cobalt(II), protoporphyrin IX cobalt, dichloro-bis-(triphenylphosphine) cobalt(II), chloro-tris(triphenylphosphine) cobalt(I), diiodo-bis(diphenylphosphino)ethane) cobalt(II), or a mixture of these. 
     
     
         8 . The electrode of  claim 18 , wherein the cobalt complex is a cobalt (III) complex. 
     
     
         9 . The electrode of  claim 18 , wherein the cobalt complex is cobalt acetylacetonate. 
     
     
         10 . The electrode of  claim 18 , wherein the solvent for the cobalt solution comprises pyridine, N,N-dimethylformamide (DMF), N,N-dimethylacetamide, N-methyl pyrrolidone (NMP), hexamethylphosphoramide (HMPA), dimethyl sulfoxide (DMSO), acetonitrile, tetrahydrofuran (THF), 1,4-dioxane, dichloromethane, chloroform, carbon tetrachloride, dichloroethane, acetone, ethyl acetate, pet ether, pentane, hexane(s), decalin, THF, dioxane, benzene, toluene, xylene(s), o-dichlorobenzene, diethyl ether, methyl t-butyl ether, methanol, ethanol, ethylene glycol, isopropanol, propanol, n-butanol, or a mixture of these. 
     
     
         11 - 17 . (canceled) 
     
     
         18 . An electrode manufactured by a method comprising:
 coating a glass substrate through evaporation and deposition of Au with a layer comprising an Au nanostructure to obtain a sintered Au nanostructure;   heating the Au nanostructure coated glass substrate at a temperature of from 475 to no greater than 600° C. in a reactor; and   introducing an aerosol of a cobalt solution comprising a cobalt complex and a solvent with a carrier comprising an inert gas to the reactor for a time of from 5 min to 20 min to form a monolaver of nanoparticles of cobalt oxide comprising CoO as the main cobalt component directly on the layer comprising the sintered Au nanostructure to obtain a multilayered catalyst structure having an interface between the layer comprising the sintered Au nanostructure and the layer of nanoparticles of cobalt oxide;   wherein the cobalt oxide nanoparticles have a diameter of from 50 to 100 nm; and   the layer comprising the Au nanostructure is not electrochemically roughened prior to the formation of the layer of cobalt oxide nanoparticles.   
     
     
         19 . (canceled) 
     
     
         20 . An electrode, comprising:
 a glass layer;   a gold layer having a thickness of 25 to 100 nm; and   an AACVD-deposited cobalt oxide layer having a thickness in a range of from 100 to 1500 nm.