A device for catalytic conversion of carbon dioxide (CO.sub.2) includes a substrate having a surface, an array of conductive projections supported by the substrate and extending outward from the surface of the substrate, each conductive projection of the array of conductive projections having a semiconductor composition, and a plurality of nanoparticles disposed over the array of conductive projections, each nanoparticle of the plurality of nanoparticles being configured for the catalytic conversion of carbon dioxide (CO.sub.2). Each nanoparticle of the plurality of nanoparticles includes a metal sulfide, the metal sulfide including a d-block metal.

An aspect of the present disclosure provides time and energy-efficient synthesis of catalysts for water electrolysis. An exemplary synthesis method includes dissolving amounts of Fe(NO.sub.3).sub.3.9H.sub.2O and Na.sub.2S.sub.2O.sub.3.5H.sub.2O in deionized water at ambient temperature to form a solution, placing Ni foam into the solution where the Ni foam serves as a substrate and a Ni source for growth of sulfur-doped (Ni,Fe)OOH (S—(Ni,Fe)OOH) catalysts, leaving the Ni foam in the solution at ambient temperature for a duration between one minute and five minutes to provide a treated foam where the S—(Ni,Fe)OOH catalysts grow on the substrate during the duration, and removing the treated foam from the solution after the duration.

An aspect of the present disclosure provides time and energy-efficient synthesis of catalysts for water electrolysis. An exemplary synthesis method includes dissolving amounts of Fe(NO.sub.3).sub.3.9H.sub.2O and Na.sub.2S.sub.2O.sub.3.5H.sub.2O in deionized water at ambient temperature to form a solution, placing Ni foam into the solution where the Ni foam serves as a substrate and a Ni source for growth of sulfur-doped (Ni,Fe)OOH (S—(Ni,Fe)OOH) catalysts, leaving the Ni foam in the solution at ambient temperature for a duration between one minute and five minutes to provide a treated foam where the S—(Ni,Fe)OOH catalysts grow on the substrate during the duration, and removing the treated foam from the solution after the duration.

A coated electrode assembly (CEA) comprising: i) a gas diffusion layer (GDE); and ii) a coating. The GDE comprises a gas diffusion layer (GDL) and a catalyst layer. The catalyst layer is disposed between the coating and the GDL. The catalyst layer comprises a hydrophobic polymer and/or an ionomeric polymer and the coating comprises a hydrophobic polymer and/or an ionomeric polymer. A method for making a CEA is provided. The CEA may have improved performance and stability compared to a membrane electrode assembly (MEA).

An electrode catalyst for a water electrolysis cell includes a catalyst, and a polymer of intrinsic microporosity having a Tröger's base skeleton containing a quaternary ammonium group. A water electrolysis cell includes an anode, a cathode, and an electrolyte membrane. The electrolyte membrane is disposed between the anode and the cathode. At least one selected from the group consisting of the anode and the cathode includes the electrode catalyst.

An electrode catalyst for a water electrolysis cell includes a catalyst, and a polymer of intrinsic microporosity having a Tröger's base skeleton containing a quaternary ammonium group. A water electrolysis cell includes an anode, a cathode, and an electrolyte membrane. The electrolyte membrane is disposed between the anode and the cathode. At least one selected from the group consisting of the anode and the cathode includes the electrode catalyst.

Electrosynthesis of oxirane can include contacting a halide electrolyte with an anode that includes an electrocatalyst comprising iridium oxide loaded with a period-6 metal oxide and provided on a metal substrate. The cathode can be operated under ORR conditions. The electrochemical system can also be provided as an integrated system that includes CO.sub.2 electroreduction to produce ethylene and formation of hypochlorous acid using the electrocatalyst, followed by contact of the ethylene and the hypochlorous acid to form ethylene chlorohydrin which is, in turn, contacted with OH.sup.− ions to produce oxirane.

Electrosynthesis of oxirane can include contacting a halide electrolyte with an anode that includes an electrocatalyst comprising iridium oxide loaded with a period-6 metal oxide and provided on a metal substrate. The cathode can be operated under ORR conditions. The electrochemical system can also be provided as an integrated system that includes CO.sub.2 electroreduction to produce ethylene and formation of hypochlorous acid using the electrocatalyst, followed by contact of the ethylene and the hypochlorous acid to form ethylene chlorohydrin which is, in turn, contacted with OH.sup.− ions to produce oxirane.

A method for ambient-temperature synthesis of a catalyst for water electrolysis by dissolving an amount of an Fe.sup.2+ source and optionally an amount of a salt of another divalent cation in deionized water at ambient temperature to form a solution, placing nickel (Ni) foam into the solution, whereby the Ni foam serves as a substrate and/or a Ni source for growth of the catalyst, leaving the Ni foam in the solution at ambient temperature for a time duration in a range of from about 0.5 hour to about 4 hours to provide a treated foam, during which time duration, the catalyst is grown on the substrate, and removing the treated foam from the solution after the time duration, wherein the treated foam comprises the catalyst grown thereon.

Aspects of the present disclosure generally relate to catalyst compositions, processes for producing such catalyst compositions, and uses of such catalyst compositions. In an embodiment, a composition is provided. The composition includes an electrolyte material or an ion thereof, an amphiphile material or an ion thereof, and a metal component, the metal component comprising an alloy having the formula (M.sup.1).sub.a(M.sup.2).sub.b, wherein M.sup.1 is a Group 10-11 metal of the periodic table of the elements, M.sup.2 is a first Group 8-11 metal of the periodic table of the elements, M.sup.1 and M.sup.2 are different, and a and b are positive numbers. In another embodiment, a device is provided that includes an electrolyte material or ion thereof, an amphiphile material or ion thereof, and a metal component disposed on an electrode, the metal component comprising a bimetallic nanoframe, a trimetallic nanoframe, or a combination thereof.