High surface area anode catalyst for aem electrolyzers

Abstract

An innovative catalyst layer composition and Anion Exchange Membrane (AEM) electrolyzer structure are disclosed, featuring meso porous particles with open pores that provide a high surface area and conductive support for anode catalysts. The composition includes a less-conductive catalyst, which is either grown on the meso porous particles through deposition processes or admixed and adsorbed by the meso porous particles. The AEM electrolyzer structure includes this catalyst layer composition, along with a cathode side containing a bipolar plate or half plate, a porous transport layer, and a catalyst layer, and an anode side similarly equipped but with a meso porous layer formed from the catalyst composition. The two sides are separated by an anion exchange membrane. Methods for manufacturing the AEM electrolyzer structure using spraying and decal processes are also disclosed, enhancing efficiency and safety for hydrogen and oxygen generation.

What is claimed is: 
     
         1 . A conductive meso porous catalyst layer for an anion exchange membrane (AEM) electrolyzer, comprising:
 a catalyst composition including meso porous particles with open pores; and   a less-conductive catalyst,   wherein the less-conductive catalyst is either grown on a surface of the meso porous particles through a growth process or admixed with the meso porous particles, and   wherein the meso porous particles are either bonded by a thermal process or held together by a binder.   
     
     
         2 . The conductive meso porous catalyst layer of  claim 1 , wherein the less-conductive catalyst is admixed with the meso porous particles and adsorbed by the meso porous particles. 
     
     
         3 . The conductive meso porous catalyst layer of  claim 1 , wherein the open pores of the meso porous particles have a size ranging from 2 nanometers to 5 micrometers. 
     
     
         4 . The conductive meso porous catalyst layer of  claim 3 , wherein the size of the open pores ranges from 5 nanometers to 1 micrometer. 
     
     
         5 . The conductive meso porous catalyst layer of  claim 4 , wherein the size of the open pores ranges between 20 nm and 500 nm in diameter. 
     
     
         6 . The conductive meso porous catalyst layer of  claim 5 , wherein the meso porous particles are composed of Raney nickel, and the meso porous particles constitute 60-95% by weight of the catalyst composition. 
     
     
         7 . The conductive meso porous catalyst layer of  claim 1 , wherein the less-conductive catalyst is at least one of nickel iron oxide (NiFe 2 O x ), Fe-LDH, FeNiCoMnCr-LDH, and NiFeCoO x , and the less-conductive catalyst constitutes 1-20% by weight of the catalyst composition. 
     
     
         8 . The conductive meso porous catalyst layer of  claim 1 , wherein the growth process includes at least one of chemical deposition, electro-chemical deposition, hydrothermal deposition, and an etching of a surface of the meso porous particles. 
     
     
         9 . The conductive meso porous catalyst layer of  claim 1 , wherein the binder is a polytetrafluoroethylene (PTFE) dispersion with a concentration of 3-15% by weight in the catalyst composition. 
     
     
         10 . The conductive meso porous catalyst layer of  claim 1 , wherein the conductive meso porous catalyst layer is bonded to an additional conductive support layer with pores having a size of up to 1 millimeter. 
     
     
         11 . The conductive meso porous catalyst layer of  claim 10 , wherein the less-conductive catalyst layer is grown or deposited onto surface areas of the additional conductive support layer with open pores. 
     
     
         12 . The conductive meso porous catalyst layer of  claim 11 , wherein the conductive meso porous catalyst layer is deposited by one of a spraying process and a decal process. 
     
     
         13 . The conductive meso porous catalyst layer of  claim 11 , wherein the additional conductive support layer with open pores is a metal foam fabricated to ensure that the less-conductive catalyst is either distributed on an outer surface of the metal foam or uniformly distributed within the open pores of the metal foam, and the additional conductive support layer with open pores is compressed. 
     
     
         14 . An AEM electrolyzer system comprising:
 an anion exchange membrane;   a cathode side with a bipolar plate or half plate, a porous transport layer, and a catalyst layer; and
 an anode side with a bipolar plate or half plate, a porous transport layer, and a conductive meso porous catalyst layer having a catalyst composition including a catalyst composition including meso porous particles with open pores, and a less-conductive catalyst, wherein the less-conductive catalyst is either grown on a surface of the meso porous particles through a growth process or admixed with the meso porous particles, and wherein the meso porous particles are either bonded by a thermal process or held together by a binder, 
   wherein the cathode side and anode side are separated by the anion exchange membrane.   
     
     
         15 . The AEM electrolyzer system of  claim 14 , wherein the porous transport layer is compressed to less than about 0.3 mm and the conductive meso porous catalyst layer of the anode side is configured to enhance electron transfer for hydrogen generation. 
     
     
         16 . A method for manufacturing an AEM electrolyzer system comprising steps of:
 providing a catalyst composition for a conductive meso porous catalyst layer including meso porous particles with open pores, and a less-conductive catalyst, wherein the less-conductive catalyst is either grown on a surface of the meso porous particles through a growth process or admixed with the meso porous particles, and wherein the meso porous particles are either bonded by a thermal process or held together by a binder;   applying the conductive meso porous catalyst layer to a porous transport layer by one of a spraying process and a decal process including the catalyst composition; and   assembling the AEM electrolyzer system with the conductive meso porous catalyst layer applied to the porous transport layer.   
     
     
         17 . The method of  claim 16 , wherein the spraying process includes use of a nitrogen airbrush. 
     
     
         18 . The method of  claim 16 , wherein the decal process includes preparing a catalyst ink including the catalyst composition onto a substrate and transferring by application of pressure in a transfer pressing process the catalyst ink after drying to the porous transport layer. 
     
     
         19 . The method of  claim 16 , further comprising the step of activating the meso porous particles to enhance catalytic activity. 
     
     
         20 . The method of  claim 16 , wherein the assembling step includes aligning bipolar plates or half plates with an anion exchange membrane and the porous transport layer having the conductive meso porous catalyst layer to form an integrated cell structure.