Carbon fiber-electrocatalysts for the oxidation of ammonia and ethanol in alkaline media and their application to hydrogen production, fuel cells, and purification processes

Abstract

Electrocatalysts useful for the oxidation of ammonia and ethanol in alkaline media. The electrocatalysts include a carbon support, a first plating layer having a strong affinity for OH, and a second plating layer having a strong affinity for oxidation of ammonia or ethanol. The carbon support may be selected from such materials as carbon fibers, carbon tubes, carbon microtubes, and carbon microspheres. The first plating layer is selected from rhodium, ruthenium, nickel and palladium and combinations thereof. The second plating layer is selected from platinum, indium, and combinations thereof. Also provided are electrolytic cells for the production of hydrogen including one or more electrocatalysts described herein, a basic electrolyte, and ammonia or ethanol. Also provided are ammonia fuel cells and ethanol fuel cells utilizing the electrocatalysts described herein.

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         24 . An electrolytic cell for the production of hydrogen, the cell comprising one or more electrocatalysts, a basic electrolyte, and ethanol;
 wherein the electrocatalyst comprises:   a carbon support selected from the group consisting of carbon fibers, carbon tubes, carbon microtubes, and carbon microspheres;   a first plating layer selected from the group consisting of rhodium, ruthenium, nickel, palladium and combinations thereof; and   a second plating layer is selected from the group consisting of platinum, iridium, and combinations thereof.   
     
     
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         30 . The electrolytic cell of  claim 24 , wherein the basic electrolyte is selected from the group consisting of potassium hydroxide, sodium hydroxide, and combinations thereof. 
     
     
         31 . The electrolytic cell of  claim 24 , wherein the basic electrolyte is added in excess of the stoichiometric proportions needed. 
     
     
         32 . The electrolytic cell of  claim 30 , wherein the basic electrolyte has a concentration in the range from about 3M to about 7M. 
     
     
         33 . The electrolytic cell of  claim 24 , wherein the ammonia is present in the cell at a concentration in the range from about 0.01 M to about 5M. 
     
     
         34 . The electrolytic cell of  claim 33 , wherein the ammonia is present in the cell at a concentration in the range from about 1M to about 2M. 
     
     
         35 . The electrolytic cell of  claim 24 , comprising one electrode comprising the electrocatalyst and a second electrode having an activity towards hydrogen evolution in alkaline media; wherein the basic electrolyte comprises potassium hydroxide having a concentration in the range from about 3M to about 7M; and ammonia having a concentration in the range from about 0.5M to about 2M. 
     
     
         36 . The electrolytic cell of  claim 35 , wherein the second electrode is selected from the group consisting of platinum, rhenium, palladium, and Raney Nickel. 
     
     
         37 . The electrolytic cell of  claim 24 , comprising two electrodes comprising the electrocatalyst; wherein the basic electrolyte comprises potassium hydroxide having a concentration of about 5M; and ammonia having a concentration of about 1M.