Electrolysis cell and electrolysis device

Abstract

An electrolysis cell 20 includes: a cathode 31 to reduce a reducible gas; an anode 41 to oxidize an oxidizable substance in an electrolytic solution, the cathode 41 containing titanium; and a separator 50 separating the cathode 31 from the anode 41 . The separator 50 includes a porous membrane. The porous membrane gives a pore size distribution defined by a graph having a horizontal axis and a vertical axis, the horizontal axis representing pore sizes of through holes of the porous membrane, the pore sizes being determined by using a porometer, the vertical axis representing a pore size flow distribution of pore volumes corresponding to the pore sizes, and the pore size distribution having a peak top in a range of not less than 0.01 μm nor more than 0.3 μm. The porous membrane has an ISO air permeance of not less than 0.8 μm/Pa·s nor more than 150 μm/Pa·s.

What is claimed is: 
     
         1 . An electrolysis cell comprising:
 a cathode configured to be in contact with a reducible gas and to reduce the reducible gas;   an anode configured to be in contact with an electrolytic solution containing an oxidizable substance and to oxidize the oxidizable substance, the anode containing titanium; and   a separator separating the cathode from the anode, wherein:   the separator includes a porous membrane;   the porous membrane gives a first pore size distribution defined by a first graph having a first horizontal axis and a first vertical axis, the first horizontal axis representing first pore sizes of through holes of the porous membrane, the first pore sizes being determined by the porometer, the first vertical axis representing a pore size flow distribution of pore volumes corresponding to the first pore sizes, and the first pore size distribution having a first peak top in not less than 0.01 μm nor more than 0.3 μm; and   the porous membrane has an ISO air permeance of not less than 0.8 μm/Pa·s nor more than 150 μm/Pa·s.   
     
     
         2 . The cell according to  claim 1 , wherein
 the porous membrane gives a second pore size distribution defined by a second graph having a second horizontal axis and a second vertical axis, the second horizontal axis representing second pore sizes of the porous membrane, the second pore sizes being determined by a mercury intrusion method, the second vertical axis representing log differential pore volumes corresponding to the second pore sizes, and the second pore size distribution having a second peak top in a range of not less than 0.05 μm nor more than 1 μm.   
     
     
         3 . The cell according to  claim 1 , wherein
 the porous membrane is an organic polymer porous membrane.   
     
     
         4 . The cell according to  claim 3 , wherein
 when the cell is operated at a current density of 200 mA/cm 2  or more for 1000 hours or more, the operated cell has titanium in at least one pore of the porous membrane.   
     
     
         5 . The cell according to  claim 4 , wherein
 an amount of the titanium in the at least one pore is defined by a mass ratio of a mass of any titanium compounds in the at least one pore to a mass of carbon in the organic polymer porous membrane, and the mass ratio is 0.0001 or more when the mass of carbon in the organic polymer porous membrane is assumed to 1.   
     
     
         6 . The cell according to  claim 4 , wherein:
 the anode has a porous substrate; and   the porous substrate contains titanium and at least one element, the at least one element being selected from the group consisting of tantalum, vanadium, molybdenum, zirconium, nickel, niobium, ruthenium, palladium, platinum, gold, yttrium, and iron.   
     
     
         7 . The cell according to  claim 5 , wherein
 when the porous membrane is divided in half thickness into a first porous part adjacent to the cathode and a second porous part adjacent to the anode, a mass of any titanium compounds in the second porous part is larger than a mass of any titanium compounds in the first porous part.   
     
     
         8 . The cell according to  claim 1 , wherein
 the cathode has:
 a porous substrate including carbon fibers; 
 a diffusion layer disposed on the porous substrate; and 
 a catalyst layer disposed on the diffusion layer, 
   the catalyst layer having a bulk density of 0.1 g/cm 3  or more and less than 0.6 g/cm 3 .   
     
     
         9 . The cell according to  claim 8 , wherein
 the porous substrate with the catalyst layer and the diffusion layer, has a bulk density of not less than 0.1 g/cm 3  nor more than 0.7 g/cm 3 .   
     
     
         10 . The cell according to  claim 1 , wherein
 the first peak top is in a range of not less than 0.01 μm nor more than 0.2 μm, and the ISO air permeance is not less than 0.8 μm/Pa·s nor more than 100 μm/Pa·s.   
     
     
         11 . The cell according to  claim 2 , wherein
 the second peak top is in a range of not less than 0.05 μm nor more than 0.8 μm.   
     
     
         12 . The cell according to  claim 1 , wherein
 the reducible gas includes carbon dioxide, and the oxidizable substance includes water or a hydroxide ion.   
     
     
         13 . The cell according to  claim 1 , wherein
 the ISO air permeability is not less than 1 μm/Pa·s nor more than 10 μm/Pa·s.   
     
     
         14 . The cell according to  claim 1 , wherein
 the first peak top is in a range of not less than 0.08 μm nor more than 0.25 μm.   
     
     
         15 . The cell according to  claim 2 , wherein
 the second peak top is in a range of not less than 0.1 μm nor more than 0.25 μm.   
     
     
         16 . The cell according to  claim 1 , wherein:
 the cathode has a surface disposed on the separator; and   the anode has a surface disposed on the separator.   
     
     
         17 . The cell according to  claim 3 , wherein
 the cell has a titanium oxide in at least one pore of the porous membrane.   
     
     
         18 . The cell according to  claim 1 , wherein
 the porous membrane includes a fluorocarbon resin, polyether, polysulfone, polyethylene, polypropylene, or cellulose.   
     
     
         19 . The cell according to  claim 5 , wherein
 an amount of the titanium in the at least one pores is defined by a mass ratio of a mass of any titanium compounds in the at least one pore to a mass of carbon in the organic polymer porous membrane, the mass ratio being 0.0001 nor more than 0.001 when the mass of carbon in the organic polymer porous membrane is assumed to 1.   
     
     
         20 . An electrolysis device comprising:
 the cell according to  claim 1 ;   a gas supply configured to supply the reducible gas to a cathode flow path of the cell; and   an electrolytic solution supply configured to supply the electrolytic solution to an anode flow path of the cell.