Apparatus and method for the compression of hydrogen gas

Abstract

An electrochemical hydrogen compression apparatus and a method for the collection and compression of hydrogen. The apparatus includes a cathode having a surface that is modified with a Tafel inhibitor that inhibits the Tafel reaction at the cathode surface. The same cathode surface may also include a Volmer catalyst to enhance the Volmer reaction at the cathode surface. The apparatus and method can advantageously increase the pressure of collected hydrogen, and may be useful for supplying the hydrogen to energy producing devices, such as a fuel cell.

What is claimed is: 
     
         1 . An apparatus for the compression of hydrogen gas, comprising:
 an anode;   a palladium cathode; and   an electrolytic medium separating the anode and the palladium cathode,   wherein the palladium cathode comprises a first palladium surface in operative contact with the electrolytic medium and a second palladium surface separated from the first palladium surface by a cathode thickness, wherein the first palladium surface comprises a Tafel inhibitor that increases the hydrogen adsorption energy of the first palladium surface.   
     
     
         2 . The apparatus recited in  claim 1 , wherein the Tafel inhibitor increases the hydrogen adsorption energy of the first palladium surface by at least about 0.3 eV for 0.5 monolayer of hydrogen surface coverage. 
     
     
         3 . The apparatus recited in  claim 1 , wherein the Tafel inhibitor is selected from the group consisting of lead, bismuth, mercury, indium, zinc, thallium, cadmium and combinations thereof. 
     
     
         4 . The apparatus recited in  claim 3 , wherein the Tafel inhibitor is selected from the group consisting of lead, bismuth and combinations thereof. 
     
     
         5 . The apparatus recited in  claim 1 , wherein the second palladium surface is substantially free of the Tafel inhibitor. 
     
     
         6 . The apparatus recited in  claim 1 , wherein the concentration of the Tafel inhibitor on the first palladium surface is at least about 0.5 μg/cm 2 . 
     
     
         7 . The apparatus recited in  claim 1 , wherein the concentration of the Tafel inhibitor on the first palladium surface is not greater than about 10 μg/cm 2 . 
     
     
         8 . The apparatus recited in  claim 1 , wherein the Tafel inhibitor is in the form of a layer deposited on the first palladium surface. 
     
     
         9 . The apparatus recited in  claim 8 , wherein the deposited layer has a thickness of not greater than one monolayer. 
     
     
         10 . The apparatus recited in  claim 1 , wherein the first palladium surface further comprises a Volmer catalyst selected from the group consisting of platinum, iridium, rhodium, ruthenium, rhenium, and combinations thereof. 
     
     
         11 . The apparatus recited in  claim 10 , wherein the Volmer catalyst comprises a metal selected from platinum, iridium and combinations thereof. 
     
     
         12 . The apparatus recited in  claim 10 , wherein the ratio of the Volmer catalyst to the Tafel inhibitor on the first palladium surface is not greater than about 5. 
     
     
         13 . The apparatus recited in  claim 10 , wherein the ratio of the of the Volmer catalyst to the Tafel inhibitor on the first palladium surface is at least about 0.1. 
     
     
         14 . The apparatus recited in  claim 1 , wherein the second palladium surface comprises a Volmer catalyst selected from the group consisting of platinum, iridium, rhodium, ruthenium, rhenium, and combinations thereof. 
     
     
         15 . The apparatus recited in  claim 1 , wherein the electrolytic medium comprises a membrane disposed between the anode and the cathode. 
     
     
         16 . The apparatus recited in  claim 15 , wherein the membrane is a proton exchange membrane. 
     
     
         17 . The apparatus recited in  claim 15 , wherein the cathode compartment contains a first electrolyte and the anode compartment contains a second electrolyte, and wherein each of the first and second electrolytes are acidic electrolytes. 
     
     
         18 . The apparatus recited in  claim 15 , wherein the cathode compartment contains a first electrolyte and the anode compartment contains a second electrolyte, and wherein the first electrolyte is an alkaline electrolyte and the second electrolyte is an acidic electrolyte. 
     
     
         19 . The apparatus recited in  claim 1 , wherein the anode comprises platinum. 
     
     
         20 . The apparatus recited in  claim 1 , further comprising a power source operatively connected to the anode and to the cathode.