Co2 electroreduction to multi-carbon products in strong acid

Abstract

The present disclosure relates to an electrode for CO 2 electroreduction in an acidic electrolyte comprising cation species, the electrode comprising: a substrate, a metal-based catalyst material, and a cation-augmenting material; wherein the cation-augmenting material comprises an acidic group exchanging protons with the cation species of the acidic electrolyte so as to increase a concentration of the cation species at a surface of the electrode.

1 . A method for manufacturing an electrode being the cathode of an electrolytic system, characterized in that the method comprising depositing a metal-based catalyst material and a cation-augmenting material onto a substrate to form a catalyst layer; and depositing the cation-augmenting material onto the catalyst layer to form a cation-augmenting layer, wherein the cation-augmenting layer has a thickness between 1.5 μm and 2 μm as determined by scanning electron microscopy and wherein the cation-augmenting material comprises an acidic group exchanging protons with cation species of the acidic catholyte so as to increase a concentration of the cation species at a surface of the electrode. 
     
     
         2 . The method according to  claim 1 , characterized in that the step of depositing the catalyst layer onto the substrate comprises sputtering a metal onto a surface of the substrate in a vacuum environment. 
     
     
         3 . The method according to  claim 1 , characterized in that the step of depositing the cation-augmenting layer onto the catalyst layer comprises spraying a cation-augmenting solution onto the catalyst layer, and the cation-augmenting solution comprising the cation-augmenting material. 
     
     
         4 . The method according to  1 , characterized in that the step of depositing the metal-based catalyst material and the cation-augmenting material comprises:
 combining the metal-based catalyst material and the cation-augmenting material to form a mixture; and   depositing the mixture onto the substrate to form an active layer.   
     
     
         5 . The method of  claim 2 , wherein the sputtering the metal is performed at a deposition rate of 1 Å/sec. 
     
     
         6 . The method of  claim 3 , wherein the sputtering the metal is performed at a deposition rate of 1 Å/sec. 
     
     
         7 . The method of  claim 1 , characterized in that, in the cathode, the metal-based catalyst material comprises or consists of copper, silver, or alloys thereof. 
     
     
         8 . The method of  claim 1 , characterized in that, in the cathode, the cation-augmenting material comprises or consists of a cationic ionomer. 
     
     
         9 . The method of  claim 1 , characterized in that, in the cathode, the acidic group is —SO 3 H. 
     
     
         10 . The method of  claim 1 , characterized in that, in the cathode, the cation-augmenting material comprises a cationic perfluorosulfonic acid (PFSA) ionomer. 
     
     
         11 . The method of  claim 10 , wherein the PFSA ionomer is composed of tetrafluoroethylene and sulfonyl fluoride vinyl ether. 
     
     
         12 . The method of  claim 1 , characterized in that, in the cathode, the cation-augmenting material further comprises carbon nanoparticles or graphite. 
     
     
         13 . The method of  claim 1 , characterized in that, in the cathode, the substrate is polytetrafluoroethylene (PTFE) that is configured for gas diffusion. 
     
     
         14 . The method of  claim 1 , wherein the step of depositing the cation-augmenting layer onto the catalyst layer comprises spraying a cation-augmenting solution onto the catalyst layer. 
     
     
         15 . The method of  claim 14 , wherein the catalyst layer has a thickness of 300 nm as determined by scanning electron microscopy. 
     
     
         16 . The method of  claim 1 , wherein the step of depositing the metal-based catalyst material and the cation-augmenting material comprises:
 combining the metal-based catalyst material and the cation-augmenting material to form a mixture; and   depositing the mixture onto the substrate to form an active layer.   
     
     
         17 . The method according to  claim 16 , characterized in that the step of combining the metal-based catalyst material and the cation-augmenting material comprises forming a homogeneous dispersion of metal nanoparticles and cationic ionomer. 
     
     
         18 . The method of  claim 17 , wherein the step of depositing the mixture comprises spraying the dispersion onto a surface of the substrate to coat the substrate with the active layer. 
     
     
         19 . The method of  claim 18 , wherein the spraying is performed in multiple sequences to form multiple active sub-layers. 
     
     
         20 . The method of  claim 18 , wherein the active layer comprises:
 a first sublayer having a thickness between 5 μm and 6 μm as determined by scanning electron microscopy,   a second sublayer having a thickness between 1.5 μm and 2 μm as determined by scanning electron microscopy, and   a third sublayer having a thickness between 1.5 μm and 2 μm as determined by scanning electron microscopy.