Two-phase solutions for electrochemically generating chemical products

Abstract

Some aspects of the present disclosure are generally directed to systems for electrochemically generating compounds, for example, for generating hydrogen peroxide or other applications. In some cases, the systems may include electrodes containing a substrate comprising non-woven fibers comprising carbon, PTFE particles on the substrate, and/or an active material, for example, carbon particles, on the substrate and/or the PTFE. In some embodiments, the systems may generate and/or flow a two-phase solution over and/or through at least a portion of an electrode. Some systems using the electrode structures and/or two-phase solution may promote the formation of three-phase boundaries, and thus may facilitate the electrocatalytic generation of certain compounds at the three-phase boundaries. Still other aspects are directed to methods of making and/or using the systems, or the like.

1 . A method, comprising:
 mixing a liquid and a gas to form a two-phase solution;   flowing the two-phase solution over and/or through at least a portion of an electrode comprising a substrate including non-woven fibers comprising carbon; and   applying a voltage to the electrode such that at least a portion of the gas participates in a reaction to electrochemically generate a compound at the electrode.   
     
     
         2 . The method of  claim 1 , further comprising a hydrophobic polymer and/or a catalyst layer on the substrate. 
     
     
         3 . The method of  claim 1 , wherein the electrode is contained in an electrochemical system having a volume of greater than or equal to 100 cm 3 , a flow rate of a liquid of the two-phase solution is greater than or equal to 30 mL/min, and/or a mass flow rate of a gas of the two-phase solution is greater than or equal to 0.2 slpm. 
     
     
         4 . The method of  claim 3 , wherein the flow rate of a liquid of the two-phase solution is greater than or equal to 200 mL/min and a mass flow rate of a gas of the two-phase solution is greater than or equal to 5 slpm. 
     
     
         5 . The method of  claim 1 , wherein the compound is hydrogen peroxide. 
     
     
         6 . The method of  claim 1 , wherein the gas comprises oxygen. 
     
     
         7 . The method of  claim 1 , wherein the liquid comprises an alkali hydroxide. 
     
     
         8 . The method of  claim 1 , wherein the liquid is flowed at a rate of at least 5 mL/min. 
     
     
         9 . The method of  claim 1 , wherein the gas is flowed at a mass flow rate of at least 0.5 slpm. 
     
     
         10 . The method of  claim 1 , wherein the electrode is a cathode in a system. 
     
     
         11 . The method of  claim 1 , wherein the hydrophobic polymer is a first hydrophobic polymer and the catalyst layer comprises a second hydrophobic polymer and/or an active material comprising carbon, and wherein the catalyst layer is formed on at least a portion of the non-woven substrate and/or the first hydrophobic polymer. 
     
     
         12 . The method of  claim 11 , wherein the active material has a surface area of greater than or equal to 5 m 2 /g and less than or equal to 500-5000 m 2 /g. 
     
     
         13 . The method of  claim 11 , wherein the first and/or second hydrophobic polymer comprises PTFE particles. 
     
     
         14 . The method of  claim 11 , wherein the catalyst layer comprises less than or equal to 0.01 wt % metal. 
     
     
         15 . A method, comprising:
 flowing a solution over at least a portion of a surface area of an electrode in a compartment;   electrochemically generating a compound in the solution at the electrode;   flowing the solution from the electrode through an outlet of the compartment; and   recirculating at least a portion of the solution from the outlet of the compartment to an inlet of the compartment such that the compound is present in the solution in an amount of greater than or equal to 0.2 wt %.   
     
     
         16 . The method of  claim 15 , further comprising flowing the recirculated solution over and/or through at least the portion of the surface area of the electrode. 
     
     
         17 . The method of  claim 15 , further comprising withdrawing at least a portion of the solution comprising the electrogenerated compound, wherein the compound is hydrogen peroxide. 
     
     
         18 . (canceled) 
     
     
         19 . The method of  claim 15 , further wherein the electrode is part of a system comprising at least one gas manifold and at least one liquid manifold, wherein the at least one gas manifold and at least one liquid manifold feeds only one intersection of a gas and liquid inlet within a cathode or anode flow plate and/or flow frame within a cell. 
     
     
         20 . The method of  claim 15 , wherein the electrode comprises a substrate including non-woven fibers comprising carbon. 
     
     
         21 . The method of  claim 20 , further comprising a hydrophobic polymer and/or a catalyst layer on the substrate. 
     
     
         22 - 26 . (canceled) 
     
     
         27 . The method of  claim 1 , wherein prior to mixing the liquid and the gas to form a two-phase solution, the gas is passed through a liquid ring compressor.