Metallic nickel/nickel-iron hydroxide catalytic layer-modified copper iodide-bismuth composite electrode and method of preparing the same and method of preparing adiponitrile using metallic nickel/nickel-iron hydroxide catalytic layer-modified copper iodide-bismuth composite electrode

Abstract

A method of preparing a metallic nickel/nickel-iron hydroxide catalytic layer-modified copper iodide-bismuth composite electrode is disclosed. The method comprises steps of: preparing a plating solution containing 0.25 M ammonium chloride, 0.067 M to 0.133 M nickel chloride, 0.067 M to 0.133 M ferrous sulfate, and 0.04 M to 2 M sodium hypophosphite; placing a copper iodide-bismuth composite electrode in the plating solution for electrodepositing metallic nickel/nickel-iron hydroxide catalytic layer onto the copper iodide-bismuth composite electrode to obtain the metallic nickel/nickel-iron hydroxide catalytic layer-modified copper iodide-bismuth composite electrode, CuI—Bi/Ni—NiFe(OH) x (r), wherein r is a molar ratio of nickel chloride to ferrous sulfate. A metallic nickel/nickel-iron hydroxide catalytic layer modified copper iodide-bismuth composite electrode and a method of preparing adiponitrile using the metallic nickel/nickel-iron hydroxide catalytic layer modified copper iodide-bismuth composite electrode are further disclosed.

What is claimed is: 
     
         1 . A method of preparing a metallic nickel/nickel-iron hydroxide catalytic layer-modified copper iodide-bismuth composite electrode, comprising steps of:
 preparing a plating solution containing 0.25 M ammonium chloride, 0.067 M to 0.133 M nickel chloride, 0.067 M to 0.133 M ferrous sulfate, and 0.04 M to 2 M sodium hypophosphite; placing a copper iodide-bismuth composite electrode in the electroplating solution to deposit metallic nickel/nickel-iron hydroxide catalytic layer onto the copper iodide-bismuth composite electrode, resulting in a metallic nickel/nickel-iron hydroxide catalytic layer-modified copper iodide-bismuth composite electrode, CuI—Bi/Ni—NiFe(OH) x (r), wherein r is a molar ratio of nickel chloride to ferrous sulfate.   
     
     
         2 . The method as claimed in  claim 1 , wherein the metallic nickel/nickel-iron hydroxide catalytic layer is electroplated onto the copper iodide-bismuth composite electrode at a constant current density of −10 mA cm −2 . 
     
     
         3 . The method as claimed in  claim 1 , wherein a time of depositing the metallic nickel/nickel-iron hydroxide catalytic layer onto the copper iodide-bismuth composite electrode ranges from 10 seconds to 60 seconds. 
     
     
         4 . A metallic nickel/nickel-iron hydroxide catalytic layer-modified copper iodide-bismuth composite electrode, CuI—Bi/Ni—NiFe(OH) x (r), prepared by the method as claimed in  claim 1 , wherein r is a molar ratio of nickel chloride to ferrous sulfate. 
     
     
         5 . A method of preparing adiponitrile using the metallic nickel/nickel-iron hydroxide catalytic layer-modified copper iodide-bismuth composite electrode as claimed in  claim 4 , comprising a step of: electrolyzing acrylonitrile at a constant current density of −100 mA cm −2  to −400 mA cm −2  in a phosphate buffer containing 0.6 M to 0.8 M acrylonitrile, using the metallic nickel/nickel-iron hydroxide catalytic layer-modified copper iodide-bismuth composite electrode as claimed in  claim 4 , to synthesize adiponitrile. 
     
     
         6 . The method as claimed in  claim 5 , wherein the metallic nickel/nickel-iron hydroxide catalytic layer-modified copper iodide-bismuth composite electrode is modified by electrodepositing a metallic nickel/nickel iron hydroxide catalytic layer with a charge passage ranging from 0.1 C cm −2  to 0.6 C cm −2 . 
     
     
         7 . The method as claimed in  claim 5 , wherein a concentration of the phosphate buffer is 0.5 M and a pH of the phosphate buffer is 8. 
     
     
         8 . The method as claimed in  claim 5 , wherein the phosphate buffer further contains 20 mM to 40 mM quaternary ammonium salt, and the quaternary ammonium salt is represented by formula (I): 
       
         
           
           
               
               
           
         
         wherein R1 to R4 are each independently a C2-5 hydrocarbon group, and X −  is ClO4 − , H2PO4 − , or Br − . 
       
     
     
         9 . The method as claimed in  claim 5 , wherein electrolysis of acrylonitrile is carried out in a H-type electrochemical cell or a flow-type electrolyzer. 
     
     
         10 . The method as claimed in  claim 9 , wherein a flow rate in the flow electrolysis system is 722 sccm.