Electrochemical reduction device

Abstract

An electrochemical reduction device includes: an electrolyte membrane; a reduction electrode including a reduction electrode catalyst layer, a diffusion layer, and a dense layer provided between the diffusion layer and the reduction electrode catalyst layer; an oxygen generating electrode; a raw material supplier that supplies the aromatic compound in a liquid state to the reduction electrode; a moisture supplier that supplies water or humidified gas to the oxygen generating electrode; and a power controller that externally applies an electric field such that the reduction electrode has an electronegative potential and the oxygen generating electrode has an electropositive potential.

What is claimed is: 
     
         1 . An electrochemical reduction device comprising:
 an electrolyte membrane having proton conductivity;   a reduction electrode including a reduction electrode catalyst layer that is provided in contact with one major surface of the electrolyte membrane and has an electron conductive material and a metal containing one or both of Pt and Pd supported by the electron conductive material, a diffusion layer that is provided near to the other major surface of the reduction electrode catalyst layer, the other major surface being opposite to the electrolyte membrane, and that causes a liquid aromatic compound and a hydride of the aromatic compound to pass through, and a dense layer provided between the diffusion layer and the reduction electrode catalyst layer;   an oxygen generating electrode provided in contact with the other major surface of the electrolyte membrane;   a raw material supplier that supplies the aromatic compound in a liquid state to the reduction electrode;   a moisture supplier that supplies water or humidified gas to the oxygen generating electrode; and   a power controller that externally applies an electric field such that the reduction electrode has an electronegative potential and the oxygen generating electrode has an electropositive potential.   
     
     
         2 . The electrochemical reduction device according to  claim 1 , wherein
 a mean flow pore diameter of the dense layer is 20 μm or less.   
     
     
         3 . The electrochemical reduction device according to  claim 1 , wherein
 a thickness of the dense layer (t) is 1 μm≦t≦50 μm.   
     
     
         4 . The electrochemical reduction device according to  claim 1 , wherein
 the dense layer contains a mixture of an electron conductive powder and a water repellent.   
     
     
         5 . The electrochemical reduction device according to  claim 4 , wherein
 amass ratio of the electron conductive powder to the water repellent in the mixture is 4 or more.   
     
     
         6 . The electrochemical reduction device according to  claim 1 , wherein
 the diffusion layer has a fiber-like shape or a shape in which many particles are solidified.   
     
     
         7 . The electrochemical reduction device according to  claim 1 , wherein
 the diffusion layer contains a carbon fiber.   
     
     
         8 . The electrochemical reduction device according to  claim 1 , wherein
 the diffusion layer contains a material having an electron conductivity of 1.0×10 −2  S/cm or more.