Oxygen evolution electrocatalysts with carbon coated cobalt (ii, iii) oxide layers

Abstract

Oxygen evolution reaction (OER) catalysts and uses thereof are described. An OER catalyst can include a carbon support, a discontinuous catalytic cobalt (II,III) oxide (Co 3 O 4 ) nanolayer in direct contact with the carbon support, and an amorphous continuous carbon layer. The Co 3 O 4 nanolayer is positioned between the carbon support and an amorphous continuous carbon layer.

1 . An oxygen evolution reaction (OER) electrocatalyst comprising:
 a carbon support;   a discontinuous catalytic cobalt nanolayer comprising a compound selected from the group consisting of CoP, CoP 2  and Co 3 O 4  that is in direct contact with the carbon support; and   an amorphous continuous carbon layer,   wherein the discontinuous catalytic cobalt nanolayer is positioned between the carbon support and the amorphous continuous carbon layer.   
     
     
         2 . The OER electrocatalyst of  claim 1 , wherein the thickness of the amorphous carbon layer is 0.5 to 15 nm. 
     
     
         3 . The OER electrocatalyst of  claim 1 , wherein the discontinuous catalytic cobalt nanolayer has a thickness of 1 to 1000 nm. 
     
     
         4 . The OER electrocatalyst of  claim 1 , wherein the carbon support is carbon fiber paper. 
     
     
         5 . The OER electrocatalyst of  claim 1 , wherein the discontinuous catalytic nanolayer comprises a Co 3 O 4  compound and the discontinuous layer further comprises Co oxide (CoO), cobalt hydroxide (Co(OH) 2 ), or both. 
     
     
         6 . The OER electrocatalyst of  claim 1 , wherein the discontinuous catalytic nanolayer comprises the CoP, CoP 2  or both. 
     
     
         7 . The OER electrocatalyst of  claim 4 , wherein the carbon support has been acid treated. 
     
     
         8 . The OER electrocatalyst of  claim 1 , wherein the discontinuous catalytic cobalt nanolayer comprises Co 3 O 4 . 
     
     
         9 . An electrode comprising the OER electrocatalyst of  claim 1 . 
     
     
         10 . An apparatus comprising the electrode of  claim 9 , wherein the apparatus is for the electrolytic splitting of water into hydrogen and oxygen, the apparatus further comprising a container for holding an aqueous electrolyte, a counter electrode, and a power source configured to apply a voltage across the electrodes. 
     
     
         11 . A method of producing the electrocatalyst of  claim 1  having a nanolayer comprising Co 3 O 4  compound, the method comprising:
 (a) obtaining a carbon support comprising a discontinuous cobalt precursor nanolayer deposited on the carbon support; 
 (b) thermally treating the carbon support from step (a) under vacuum to convert the cobalt species to CoO; and 
 (c) thermally treating the carbon support from step (b) in an oxygen-rich environment to convert the CoO Co 3 O 4 . 
 
     
     
         12 . The method of  claim 11 , wherein the carbon support from step (a) comprises a carbon-containing layer deposited on the discontinuous cobalt precursor layer, and wherein the thermal treating steps (b) and/or (c) convert the carbon-containing layer into an amorphous carbon layer, wherein the amorphous carbon layer is continuous. 
     
     
         13 . The method of  claim 11 , wherein the carbon support material comprises carbon paper. 
     
     
         14 . The method of  claim 11 , wherein obtaining the carbon support material of step (a) comprises:
 (i) acid treating the carbon support; and   (ii) contacting the acid treated carbon support with the cobalt precursor under conditions sufficient to deposit the discontinuous cobalt precursor nanolayer on the surface of the carbon support.   
     
     
         15 . The method of  claim 14 , wherein the deposition in step (ii) is electrochemical deposition (ECD), atomic layer deposition (ALD) or chemical vapor deposition (CVD). 
     
     
         16 . The method of  claim 12 , wherein the carbon-containing layer comprises a hydrocarbon, a sugar-based compound, a sulfonated carbon compound, nitrogen-based carbon compound, carbon-based monomer, aromatic compound, or any combination thereof, preferably glucose. 
     
     
         17 . The method of  claim 11 , wherein the amorphous carbon layer has a thickness of 0.5 nm to 15 nm. 
     
     
         18 . A method of producing the OER electrocatalyst of  claim 1  having a nanolayer comprising the CoP compound the CoP 2  compound or both, the method comprising:
 contacting a carbon support material having a cobalt precursor deposited thereon; and 
 thermally treating the cobalt precursor and reacting with a phosphorous source in an oxygen deficient atmosphere to produce the CoP and/or CoP 2  nanolayer on the carbon support. 
 
     
     
         19 . A method for the electrolytic splitting of water into hydrogen and/or oxygen, the method comprising:
 electrolyzing an aqueous solution comprising electrolyte and the OER catalysts of  claim 1 ; and   producing hydrogen gas and oxygen gas.   
     
     
         20 . The OER electrocatalyst of  claim 19 , wherein the aqueous solution is an acidic solution or a basic solution.