Electrochemical catalyst for conversion of co2 to ethanol

Abstract

An electrocatalyst comprising (i) carbon nanospikes and (ii) copper-containing nanoparticles residing on and/or embedded between said carbon nanospikes. The carbon nanospikes are doped with a dopant selected from the group consisting of nitrogen, boron, and phosphorous. Also disclosed herein is a method of producing the eletrocatalyst and a method for converting carbon dioxide into ethanol by use of the above-described electrocatalyst.

What is claimed is: 
     
         1 . An electrocatalyst comprising (i) carbon nanospikes and (ii) copper-containing nanoparticles residing on and/or embedded between said carbon nanospikes, wherein said carbon nanospikes are doped with a dopant selected from the group consisting of nitrogen, boron, and phosphorous. 
     
     
         2 . The electrocatalyst of  claim 1 , wherein said carbon nanospikes contain layers of puckered carbon. 
     
     
         3 . The electrocatalyst of  claim 1  wherein at least a portion of the carbon nanospikes contain a straight or curled tip. 
     
     
         4 . The electrocatalyst of  claim 3 , wherein said straight or curled tip has a width ranging from 0.5 nm to 3 nm. 
     
     
         5 . The electrocatalyst of  claim 1 , wherein said carbon nanospikes have a length ranging from 20 nm to 100 nm. 
     
     
         6 . The electrocatalyst of  claim 1 , wherein said electrocatalyst is disposed on a semiconductive substrate or a conductive substrate. 
     
     
         7 . The electrocatalyst of  claim 1 , wherein said electrocatalyst is electrically connected to a counter electrode. 
     
     
         8 . The electrocatalyst of  claim 1 , wherein said copper-containing nanoparticles comprise copper or a copper alloy. 
     
     
         9 . The electrocatalyst of  claim 1 , wherein said copper-containing nanoparticles have a size ranging from 1 nm to 500 nm. 
     
     
         10 . The electrocatalyst of  claim 1 , wherein said copper-containing nanoparticles are present on said carbon nanospikes in a density ranging from 0.5×10 10  particles/cm 2  to 3.0×10 10  particles/cm 2 . 
     
     
         11 . The electrocatalyst of  claim 1 , wherein a concentration of the dopant in said nanospikes is from 3 atomic % to 9 atomic %. 
     
     
         12 . A method of producing an electrocatalyst for converting carbon dioxide to ethanol, the method comprising;
 providing a mat of carbon nanospikes protruding outwardly from a surface of said mat, wherein said carbon nanospikes are doped with a dopant selected from the group consisting of nitrogen, boron, and phosphorous; and   forming copper-containing nanoparticles on and/or between said carbon nanospikes.   
     
     
         13 . The method of  claim 12 , wherein said copper-containing nanoparticles are formed by immersing said mat of carbon nanospikes into an aqueous solution containing a copper salt, and applying a reducing voltage onto said mat of carbon nanospikes to reduce copper ions in said copper salt to elemental copper. 
     
     
         14 . The method of  claim 12 , wherein said copper nanoparticles are formed by physical or chemical vapor deposition of copper. 
     
     
         15 . The method of  claim 12 , wherein said copper nanoparticles are formed by electroless deposition of copper from a solution containing a copper salt and a reducing agent, wherein said solution is in contact with said mat of carbon nanospikes. 
     
     
         16 . The method of  claim 12 , wherein said copper nanoparticles are formed ex situ and deposited on said mat of carbon nanospikes. 
     
     
         17 . A method of converting carbon dioxide into ethanol, the method comprising contacting an electrocatalyst with an aqueous solution of a bicarbonate salt while said aqueous solution is in contact with a source of carbon dioxide, which replenishes said bicarbonate salt as said bicarbonate salt decomposes to carbon dioxide and a hydroxide salt at a surface of said electrocatalyst, and said electrocatalyst is electrically powered as a cathode and is in electrical communication with a counter electrode electrically powered as an anode, wherein a voltage across said cathode and said anode is within a range of 2 to 4 volts, to convert said carbon dioxide into ethanol; wherein said electrocatalyst comprises (i) carbon nanospikes and (ii) copper-containing nanoparticles residing on and/or embedded between said carbon nanospikes, wherein said carbon nanospikes are doped with a dopant selected from the group consisting of nitrogen, boron, and phosphorous. 
     
     
         18 . The method of  claim 17 , wherein said ethanol is deuterated ethanol. 
     
     
         19 . The method of  claim 17 , wherein said electrocatalyst is housed in a first compartment of an electrochemical cell, wherein said first compartment contains said aqueous solution in contact with said electrocatalyst; said counter electrode is housed in a second compartment of said electrochemical cell, wherein said second compartment also contains said aqueous solution, and said first compartment and second compartment are separated by a solid electrolyte membrane. 
     
     
         20 . The method of  claim 17 , wherein said bicarbonate salt is KHCO 3  or NaHCO 3 . 
     
     
         21 . The method of  claim 17 , wherein said bicarbonate salt has a concentration ranging from 0.1 M to 0.5 M. 
     
     
         22 . The method of  claim 17 , wherein said carbon dioxide is bubbled into said aqueous solution before or during said electrocatalyst is in contact with said aqueous solution. 
     
     
         23 . The method of  claim 17 , wherein said ethanol is produced in a yield of at least 60% relative to total product produced, as measured by electron current. 
     
     
         24 . The method of  claim 17 , wherein no ethane or ethylene is produced.