Method for preventing salt precipitation in a zero-gap co2 reduction electrolyzer

Abstract

A method for preventing salt precipitation in zero-gap CO 2 reduction electrolyzers utilizes an ammonium salt solution as electrolyte. For CO 2 reduction operation, CO 2 gas and/or the ammonium salt solution is fed to the cathode chamber comprising a gas diffusion electrode, while the ammonium salt solution is fed to the anode chamber also comprising a gas diffusion electrode. This use of an ammonium salt solution effectively prevents salt precipitation within the pores of the cathode gas diffusion electrode, thereby improving the selectivity of electrochemical CO 2 reduction products.

What is claimed is: 
     
         1 . A method for preventing salt precipitation in a zero-gap CO 2  reduction electrolyzer, the method comprising:
 a. preparing an ammonium salt solution, wherein the ammonium salt is represented by the formula [N(R1)(R2)(R3)(R4)]X; and wherein R1, R2, R3, and R4 are each independently selected from —H, —CH 3 , —CH 2 CH 3 ;   b. loading a catalyst onto a cathode gas diffusion layer to form a cathode gas diffusion electrode for a CO 2  reduction reaction;   c. loading a catalyst onto an anode gas diffusion layer to form an anode gas diffusion electrode for a water oxidation reaction; and   d. testing CO 2  reduction performance in the zero-gap CO 2  reduction electrolyzer, wherein: CO 2 , the ammonium salt solution obtained in step (a), or both, are supplied to the cathode gas diffusion electrode obtained in step (b) through a cathode chamber; and the ammonium salt solution obtained in step (a) is supplied to the anode gas diffusion electrode obtained in step (c) through an anode chamber.   
     
     
         2 . The method of  claim 1 , wherein in step (d), the zero-gap CO 2  reduction electrolyzer further comprises a cathode chamber, a cathode gas diffusion electrode, an anode chamber, an anode gas diffusion electrode, and an ion exchange membrane. 
     
     
         3 . The method of  claim 1 , wherein in step (a), the concentration of the ammonium salt ranges from 0.001 mol L −1  to 3 mol L −1 . 
     
     
         4 . The method of  claim 1 , wherein in step (a), X is an anion. 
     
     
         5 . The method of  claim 1 , wherein in step (b), the cathode gas diffusion layer comprises carbon paper. 
     
     
         6 . The method of  claim 1 , wherein in step (b), the catalyst comprises a silver-based catalyst or a copper-based material.