Catalytic compositions and methods of preparing thereof

Abstract

The invention provides a catalytic composition, the catalytic composition comprising copper oxide nanoparticles, carbon black, and a binder. The invention also provides a catalyst, an electrode and an electrolyser comprising the catalytic composition. In addition, the invention provides a method of preparing a catalytic composition, the method comprising (a) providing a binder in a solvent to provide a binder mixture; (b) incorporating carbon black into the binder mixture; (c) incorporating copper oxide nanoparticles into the binder mixture; and (d) stirring the mixture to form a composite material of the binder, carbon black, and copper oxide nanoparticles. The invention also provides a method of producing hydrogen comprising contacting an aqueous electrolyte with the catalytic composition, the catalyst, or the electrode, and applying a voltage sufficient to split water into hydrogen and oxygen.

Description

[0001] CATALYTIC COMPOSITIONS AND METHODS OF PREPARING THEREOF

[0002] FIELD OF INVENTION

[0003] The present invention provides catalytic compositions, more particularly, catalytic compositions comprising copper oxide nanoparticles, carbon black and a binder. The catalytic compositions according to the present disclosure is particularly useful in producing green hydrogen.

[0004] BACKGROUND

[0005] The listing or discussion of a prior-published document in this specification should not necessarily be taken as an acknowledgement that the document is part of the state of the art or is common general knowledge.

[0006] In the contemporary industrial hydrogen production through membrane-based water electrolysis process, platinum serves as the cathode catalyst, while iridium is employed as the anode catalyst. To facilitate the extensive integration of hydrogen-based technologies, it is imperative to pioneer the development of novel catalysts that exhibit superior activity and extended durability, are of low cost, and are earth-abundant. This pursuit centres on the utilization of readily available and economically viable materials, which can potentially revolutionize the hydrogen production landscape, making it more sustainable and economically feasible for widespread adoption of green hydrogen production. Metal / metal oxide nanostructures can replace the highly expensive catalyst for the process.

[0007] Cupric oxide (CuO) shows promising results for hydrogen production through photoelectrochemical water splitting. Furthermore, CuO also acts as a co-catalyst for the hydrogen production reaction. As CuO is cheap, abundant and easily synthesized, it is very suitable for large scale adoption for hydrogen production. The main challenges for CuO are its high resistance and stability in electrolyte. Performance of hydrogen and oxygen evaluation depends on the composition and thickness of the catalysts. For examples, aluminium and / or titanium incorporated CuO provides high conductivity and active surface area for catalytic activity. In addition, it also reduces the band gap of CuO and thus helps to charge transfer from electrolyte to electrode.

[0008] Thus, there is a need for alternative and / or improved catalysts / catalytic compositions suitable for producing green hydrogen via photoelectrochemical water splitting. SUMMARY

[0009] Aspects and embodiments of the current invention will now be described by reference to the following numbered clauses.

[0010] 1 . A catalytic composition, the catalytic composition comprising: copper oxide nanoparticles; carbon black; and a binder.

[0011] 2. The catalytic composition according to Clause 1 , wherein the composition comprises from about 5wt% to about 60wt% copper oxide nanoparticles, such as about 7wt% to about 55wt% copper oxide nanoparticles, such as about 10wt% to about 50wt% copper oxide nanoparticles.

[0012] 3. The catalytic composition according to Clause 1 or Clause 2, wherein the copper oxide nanoparticles have a diameter of from about 20 nm to about 80 nm, such as about 30 nm to about 70 nm, such as about 35 nm to about 65 nm, such as about 40 nm to about 60 nm.

[0013] 4. The catalytic composition according to any preceding clause, wherein the copper oxide nanoparticles are cupric oxide (CuO) nanoparticles.

[0014] 5. The catalytic composition according to any preceding clause, wherein the composition comprises from about 1 wt% to about 40wt% carbon black, such as from about 2wt% to about 35wt% carbon black, such as from about 5wt% to about 30wt% carbon black.

[0015] 6. The catalytic composition according to any preceding clause, wherein the composition comprises from about 1wt% to about 10wt% binder.

[0016] 7. The catalytic composition according to any preceding clause, wherein the binder is selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), an anion- exchange ionomer (e.g., Sustainion®), polybenzimidazole (PBI), polyurethane, an epoxy resin, polysulfone, polyether ether ketone (PEEK), polyacrylic acid (PAA), polyvinyl alcohol (PVA), or a combination thereof.

[0017] 8. The catalytic composition according to any preceding clause, wherein the catalytic composition further comprises one or more metal oxides, optionally wherein the metal oxide is one or more of aluminium oxide (AI2O3), titanium oxide (TiO2), and iron (III) oxide (Fe2O3), cerium oxide (CeO2), zirconium oxide (ZrO2), manganese oxide (MnO2or Mn2O3), cobalt oxide (Co304), nickel oxide (NiO), tin oxide (SnO2), indium-tin oxide (ITO), silica (SiO2), zinc oxide (ZnO), and vanadium oxide (V2O5), further optionally wherein the metal oxide is one or more of AI2O3, TiO2, and Fe2O3.

[0018] 9. The catalytic composition according to Clause 8, wherein the composition comprises from about 0.1 wt% to about 25wt% of the one or more metal oxides with respect to the copper oxide nanoparticles, such as about 0.5wt% to about 22wt% of the one or more metal oxides, such as about 1wt% to about 20wt% of the one or more metal oxides.

[0019] 10. The catalytic composition according to any preceding clause, wherein the composition further comprises a co-catalyst.

[0020] 11 . The catalytic composition according to Clause 10, wherein the co-catalyst comprises one or both of a metal alloy and a metal alloy oxide.

[0021] 12. The catalytic composition according to Clause 1 1 , wherein the metal alloy or metal alloy oxide is a ternary metal alloy or ternary metal alloy oxide.

[0022] 13. The catalytic composition according to Clause 12, wherein the ternary metal alloy or the ternary metal alloy oxide comprises metals selected from nickel, iron, molybdenum, manganese, tungsten, copper and cobalt, optionally wherein the ternary metal alloy or the ternary metal alloy oxide comprises nickel-iron-molybdenum, nickel-iron-manganese, nickel-iron-tungsten, cobalt-manganese-iron, nickel-cobalt-molybdenum, or nickelcopper-iron.

[0023] 14. The catalytic composition according to any preceding clause, wherein the composition further comprises graphene, optionally wherein the graphene is functionalised, optionally wherein the functionalised graphene comprises carboxyl graphene.

[0024] 15. The catalytic composition according to Clause 14, wherein the composition comprises from about 0.1 wt% to about 15wt% graphene, such as from about 0.5wt% to about 12wt% graphene, such as from about 1wt% to about 10wt% graphene. 16. The catalytic composition according to any preceding clause, wherein the ratio of copper oxide nanoparticles to the carbon black is from about 1 :1 to about 4:1 , such as about 2:1 to about 3:1 (wt:wt).

[0025] 17. A catalyst comprising the catalytic composition according to any of Clauses 1 to 16 provided on a support, optionally wherein the support is a metal foam support, optionally a nickel metal foam support.

[0026] 18. The catalyst according to Clause 17, wherein the catalyst exhibits an overpotential of less than 300 mV at 100 mA / cm2in 1 M KOH.

[0027] 19. A method of preparing a catalytic composition, the method comprising: a) providing a binder in a solvent to provide a binder mixture; b) incorporating carbon black into the binder mixture; c) incorporating copper oxide nanoparticles into the binder mixture; and d) stirring the mixture to form a composite material of the binder, carbon black, and copper oxide nanoparticles.

[0028] 20. The method according to Clause 19, wherein the method further comprises incorporating graphene such that the graphene is incorporated into the composite material.

[0029] 21 . The method according to Clause 19 or Clause 20, wherein the solvent is selected from one or more of NMP, DMF, and cyclohexane.

[0030] 22. The method according to any of Clauses 19 to 21 , wherein the method further includes incorporating one or more metal oxides, such as one or more of aluminium oxide (AI2O3), titanium oxide (TiO2), and iron (III) oxide (Fe2O3) cerium oxide (CeO2), zirconium oxide (ZrO2), manganese oxide (MnO2or Mn2O3), cobalt oxide (Co3O4), nickel oxide (NiO), tin oxide (SnO2), indium-tin oxide (ITO), silica (SiO2), zinc oxide (ZnO), and vanadium oxide (V2O5), such as one or more of AI2O3, TiO2, and Fe2Os, into the binder mixture.

[0031] 23. The method according to any of Clauses 19 to 22, wherein the method further includes incorporating a co-catalyst into the binder mixture, optionally wherein the co-catalyst comprises one or both of a metal alloy and a metal alloy oxide, optionally wherein the metal alloy or metal alloy oxide is a ternary metal alloy or ternary metal alloy oxide, optionally wherein the ternary metal alloy or the ternary metal alloy oxide comprises metals selected from nickel, iron, molybdenum, manganese, tungsten, copper and cobalt, optionally wherein the ternary metal alloy or the ternary metal alloy oxide comprises nickel-iron-molybdenum, nickel-iron- manganese, nickel-iron-tungsten, cobalt-manganese-iron, nickel-cobalt-molybdenum, or nickel-copper-iron.

[0032] 24. The method according to any of Clauses 19 to 23, wherein the method further includes: e) coating a support with the binder mixture to provide a coated support.

[0033] 25. The method according to Clause 24, wherein the method further includes: f) heating the coated support in air at a temperature of from about 150 to about 500°C, such as from about 200 to about 400°C, optionally wherein the coated support is heated for up to about 5 hours, up to about 4 hours, up to about 3 hours, up to about 2 hours, or up to about 1 hour.

[0034] 26. The method according to Clause 24 or Clause 25, wherein the method further includes plasma treating the support prior to coating, optionally wherein plasma treating the support comprises exposing the support to a low-temperature plasma selected from oxygen plasma, argon plasma, and hydrogen plasma.

[0035] 27. An electrode for an electrochemical device, the electrode comprising the catalytic composition or catalyst according to any of Clauses 1 to 18, optionally wherein the electrode is a membrane electrode assembly, optionally wherein the electrochemical device is selected from an electrolyser, a fuel cell, a battery, a supercapacitor, a photoelectrochemical cell, a flow battery, and an electrochemical sensor.

[0036] 28. An electrolyser comprising the catalytic composition, catalyst, or electrode according to any of Clauses 1 to 18, and 27.

[0037] 29. A method of producing hydrogen comprising contacting an aqueous electrolyte with the catalytic composition, catalyst, or electrode according to any of Clauses 1 to 18 and 27, and applying a voltage sufficient to split water into hydrogen and oxygen.

[0038] 30. Use of the catalytic composition, catalyst, electrode, or electrolyser according to any of Clauses 1 to 18, 27, and 28 for generating hydrogen.

[0039] BRIEF DESCRIPTION OF DRAWINGS FIG. 1(a) depicts the linear sweep voltammetry analysis of various electrodes (Bare NF, C- PVDF 400, CuO-PVDF on NF 400 and CuO-C-PVDF on NF 400) according to Example 1 of the present disclosure. FIG. 1 (b) depicts the stability analysis of CuO-C-PVDF on NF according to Example 1 (i) of the present disclosure.

[0040] FIG. 2 depicts the linear sweep voltammetry analysis of various electrodes (Bare NF, CuO- PVDF on NF 100, CuO-PVDF on NF 400 and CuO-PVDF on NF 500) according to Example 1 (11) of the present disclosure.

[0041] FIG. 3 depicts the linear sweep voltammetry analysis of various electrodes (Bare NF, CuO-C- PVDF on NF 100 and 2CuO-C-PVDF on NF 100) according to Example 1 (iii) of the present disclosure.

[0042] FIG. 4 depicts the linear sweep voltammetry analysis of various electrodes (Bare NF, 2CuO- C-PVDF100 dip10 mins, 2CuO-C-PVDF100 dip 20 mins, 2CuC-C-PVDF400 dip 10 mins and 2CuO-C-PVDF400 dip 20 mins) according to Example 1 (iv) of the present disclosure.

[0043] FIG. 5 depicts the linear sweep voltammetry analysis of various electrodes (Bare NF, CuO- AI2O3-C-PVDF 400, CuO-TiO2-C-PVDF 400, Cu0-Zn0-Fe203 / Fe30-C-PVDF400 and CuO:AI-C-PVDF 400) according to Example 2 of the present disclosure.

[0044] FIG. 6 depicts the linear sweep voltammetry analysis of various electrodes (2CuO-G-C-PVDF on NF 400 and 3CuO-G-C-PVDF on NF 400) according to Example 3(i) of the present disclosure.

[0045] FIG. 7 depicts (a) the energy-dispersive X-ray spectroscopy (EDX) analysis, (b) the scanning electron microscopy (SEM) images and the elemental mapping analysis of 3CuO-G-C- PVDF400 according to Example 3(i) of the present disclosure.

[0046] FIG. 8 depicts the linear sweep voltammetry analysis of various electrodes (2CuO-G-C-PVDF on NF 400, 2CuO-2G-C-PVDF on NF 400 and 2CuO-4G-C-PVDF on NF 400) accorcling to Example 3(ii) of the present disclosure.

[0047] FIG. 9 depicts the FTIR spectra of the CuO-NiFeCo-C-PVDF400 composite catalyst according to Example 5 of the present disclosure. FIG. 10(a) depicts the current-potential (l-V) response of the 2CuO-2G-C-PVDF400 working electrode (WE) using Pt as the counter electrode (CE) according to Example 4 of the present disclosure. This setup represents a conventional electrochemical cell configuration with a noble metal CE.

[0048] FIG. 10(b) depicts the l-V response of the 2CuO-2G-C-PVDF400 working electrode using a matching 2CuO-2G-C-PVDF100 counter electrode according to Example 4 of the present disclosure, representing a symmetric or dual-electrode system composed entirely of nonnoble, active material.

[0049] DESCRIPTION

[0050] The present inventors have developed CuO composite as catalysts / co-catalysts for hydrogen and oxygen production through water splitting by incorporating metal and metal alloy which effectively enhances the catalytic process and produces hydrogen and oxygen more effectively. These catalysts are also environmentally friendly and earth-abundant and can be synthesized for large scale production. The catalysts are sustainable and can be produced for large scale deployment of electrolyser for green hydrogen production.

[0051] The advantages of the present invention lies in the following: 1 ) in-situ doping engineering of copper-based metal oxide through solution, 2) CuO based composite formation using solution process, and 3) active surface area enhancement through incorporating graphene, 4) interface charge transfer property enhances through thermal treatment and dopant activation of the oxide layer.

[0052] Thus, in a first aspect of the invention, there is provided a catalytic composition, the catalytic composition comprising: copper oxide nanoparticles; carbon black; and a binder.

[0053] In embodiments herein, the word “comprising” may be interpreted as requiring the features mentioned, but not limiting the presence of other features. Alternatively, the word “comprising” may also relate to the situation where only the components / features listed are intended to be present (e.g. the word “comprising” may be replaced by the phrases “consists of” or “consists essentially of”). It is explicitly contemplated that both the broader and narrower interpretations can be applied to all aspects and embodiments of the present invention. In other words, the word “comprising” and synonyms thereof may be replaced by the phrase “consisting of” or the phrase “consists essentially of’ or synonyms thereof and vice versa.

[0054] The phrase, “consists essentially of’ and its pseudonyms may be interpreted herein to refer to a material where minor impurities may be present. For example, the material may be greater than or equal to 90% pure, such as greater than 95% pure, such as greater than 97% pure, such as greater than 99% pure, such as greater than 99.9% pure, such as greater than 99.99% pure, such as greater than 99.999% pure, such as 100% pure.

[0055] When used herein, the term “nanoparticle” refers to nanoscale particles, ranging in size between 1 and 100 nm. As noted herein, the copper oxide nanoparticles may have a diameter of from about 20 nm to about 80 nm, such as about 30 nm to about 70 nm, such as about 35 nm to about 65 nm, such as about 40 nm to about 60 nm, as measured by any suitable method or device, such as a particle size analyser (PSA).

[0056] In certain embodiments, the catalytic composition may comprise from about 5wt% to about 60wt% copper oxide nanoparticles, such as about 7wt% to about 55wt% copper oxide nanoparticles, such as about 10wt% to about 50wt% copper oxide nanoparticles.

[0057] The term “about” as used herein can allow for a degree of variability in a value or range, for example, within 10%, within 5%, within 1%, within 0.5%, within 0.1%, within 0.05%, within 0.01 %, within 0.005%, or within 0.001% of a stated value or of a stated limit of a range, and includes the exact stated value or range.

[0058] For the avoidance of doubt, it is explicitly contemplated that where a number of numerical ranges related to the same feature are cited herein, that the end points for each range are intended to be combined in any order to provide further contemplated (and implicitly disclosed) ranges. Thus, in relation to the above related numerical ranges, there is disclosed a concentration of: from 5 wt% to 10 wt%, from 5 wt% to 20 wt%, from 5 wt% to 30 wt%, from 5 wt% to 40 wt%, from 5 wt% to 50 wt%, from 5 wt% to 55 wt%, from 5 wt% to 60 wt%; from 10 wt% to 20 wt%, from 10 wt% to 30 wt%, from 10 wt% to 40 wt%, from 10 wt% to 50 wt%, from 10 wt% to 55 wt%, from 10 wt% to 60 wt%; from 20 wt% to 30 wt%, from 20 wt% to 40 wt%, from 20 wt% to 50 wt%, from 20 wt% to 55 wt%, from 20 wt% to 60 wt%; from 30 wt% to 40 wt%, from 30 wt% to 50 wt%, from 30 wt% to 55 wt%, from 30 wt% to 60 wt%; from 40 wt% to 50 wt%, from 40 wt% to 55 wt%, from 40 wt% to 60 wt%; from 50 wt% to 55 wt%, from 50 wt% to 60 wt%; and from 55 wt% to 60 wt%.

[0059] In certain embodiments, the copper oxide nanoparticles may be cupric oxide (CuO) nanoparticles.

[0060] Carbon black may be present in any suitable amount. In certain embodiments, the composition may comprise from about 1wt% to about 40wt% carbon black, such as from about 2wt% to about 35wt% carbon black, such as from about 5wt% to about 30wt% carbon black.

[0061] Any suitable binder may be used in the catalytic composition. In certain embodiments, the binder may be selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), an anion-exchange ionomer (e.g., Sustainion®), polybenzimidazole (PBI), polyurethane, an epoxy resin, polysulfone, polyether ether ketone (PEEK), polyacrylic acid (PAA), polyvinyl alcohol (PVA) or a combination thereof. In certain exemplary embodiments, the binder may be polyvinylidene fluoride (PVDF).

[0062] The binder may be present in any suitable amount. In certain embodiments, the composition may comprise from about 1wt% to about 10wt% binder.

[0063] In certain embodiments, the catalytic composition may further comprise one or more metal oxides. Advantageously, the metal oxide improves the electrochemical performance of the CuO composite, characterised by reduced overpotential and increased cell current, as a result of metal doping in CuO which influences band gap alignment, energy levels, conductivity of the CuO, and thus, charge separation and transfer is significantly improved.

[0064] In certain embodiments, the metal oxide may be one or more of aluminium oxide (AI2O3), titanium oxide (TiO2), and iron (III) oxide (Fe2O3), cerium oxide (CeO2), zirconium oxide (ZrO2), manganese oxide (MnO2or Mn2O3), cobalt oxide (Co304), nickel oxide (NiO), tin oxide (SnO2), indium-tin oxide (ITO), silica (SiO2), zinc oxide (ZnO), and vanadium oxide (V2O5). In certain exemplary embodiments, the metal oxide may be one or more of AI2O3, TiO2, and Fe2O3.

[0065] The one or more metal oxides may be present in any suitable amount. In certain embodiments, the composition may comprise from about 0.1 wt% to about 25wt% of the one or more metal oxides with respect to the copper oxide nanoparticles, such as about 0.5wt% to about 22wt% of the one or more metal oxides, such as about 1 wt% to about 20wt% of the one or more metal oxides.

[0066] In certain embodiments, the catalytic composition may further comprise a co-catalyst. In more particular embodiments, the co-catalyst may comprise one or both of a metal alloy and a metal alloy oxide. In even more particular embodiments, the metal alloy or metal alloy oxide may be a ternary metal alloy or ternary metal alloy oxide. Advantageously, the ternary metal alloy or ternary metal oxides provide more active sites for electrochemical activity, reaction kinetics and stability. The catalytic composition may comprise from about 35wt% to about 85wt%, such as about 40wt% to about 80wt%, of the co-catalyst.

[0067] In certain embodiments, the ternary metal alloy or the ternary metal alloy oxide may comprise metals selected from nickel, iron, molybdenum, manganese, tungsten, copper and cobalt. In more particular embodiments, the ternary metal alloy or the ternary metal alloy oxide may comprise nickel-iron-molybdenum, nickel-iron-manganese, nickel-iron-tungsten, cobaltmanganese-iron, nickel-cobalt-molybdenum, or nickel-copper-iron.

[0068] In certain embodiments, the catalytic composition may further comprise graphene. In more particular embodiments, the graphene may be functionalised. In certain exemplary embodiments, the functionalised graphene may comprise carboxyl graphene. Advantageously, the functionalized graphene provides high surface area and enhanced conductivity of the catalytic composition.

[0069] The graphene may be present in any suitable amount. In certain embodiments, the composition may comprise from about 0.1 wt% to about 15wt% graphene, such as from about 0.5wt% to about 12wt% graphene, such as from about 1wt% to about 10wt% graphene.

[0070] In certain embodiments, the ratio of copper oxide nanoparticles to the carbon black is from about 1 :1 to about 4:1 , such as about 2:1 to about 3:1 (wt:wt).

[0071] In another aspect of the invention, there is provided a catalyst comprising the catalytic composition as disclosed hereinbefore provided on a support. As details of the catalytic composition have already been described above, they are omitted here for brevity.

[0072] In certain embodiments, the support may be a metal foam support. In certain exemplary embodiments, the support may be a nickel metal foam support. As demonstrated in the Examples of the present disclosure, the catalyst exhibit improved electrochemical performance. In certain embodiments, the catalyst may exhibit an overpotential of less than 300 mV at 100 mA / cm2in 1 M KOH.

[0073] As demonstrated in the Examples of the present disclosure, the catalytic composition may be prepared by a solution method. As such, in another aspect of the invention, there is provided a method of preparing a catalytic composition, the method comprising: a) providing a binder in a solvent to provide a binder mixture; b) incorporating carbon black into the binder mixture; c) incorporating copper oxide nanoparticles into the binder mixture; and d) stirring the mixture to form a composite material of the binder, carbon black, and copper oxide nanoparticles.

[0074] In certain embodiments, the method may further comprise incorporating graphene such that the graphene is incorporated into the composite material.

[0075] Any suitable solvent may be used. In certain embodiments, the solvent may be selected from one or more of N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), and cyclohexane.

[0076] In certain embodiments, the method may further include incorporating one or more metal oxides, such as one or more of aluminium oxide (AI2O3), titanium oxide (TiO2), and iron (III) oxide (Fe2O3) cerium oxide (CeO2), zirconium oxide (ZrO2), manganese oxide (MnO2or Mn2O3), cobalt oxide (Co3O4), nickel oxide (NiO), tin oxide (SnO2), indium-tin oxide (ITO), silica (SiO2), zinc oxide (ZnO), and vanadium oxide (V2O5) into the binder mixture. In certain exemplary embodiments, the method may further include incorporating one or more of AI2O3, TiO2, and Fe2Os, into the binder mixture.

[0077] In certain embodiments, the method may further include incorporating a co-catalyst into the binder mixture. In more particular embodiments, the co-catalyst may comprise one or both of a metal alloy and a metal alloy oxide. In even more particular embodiments, the metal alloy or metal alloy oxide may be a ternary metal alloy or ternary metal alloy oxide. In certain embodiments, the ternary metal alloy or the ternary metal alloy oxide may comprise metals selected from nickel, iron, molybdenum, manganese, tungsten, copper and cobalt. In more particular embodiments, the ternary metal alloy or the ternary metal alloy oxide may comprise nickel-iron-molybdenum, nickel-iron-manganese, nickel-iron-tungsten, cobaltmanganese-iron, nickel-cobalt-molybdenum, or nickel-copper-iron. In certain embodiments, wherein the method may further include: e) coating a support with the binder mixture to provide a coated support.

[0078] In certain embodiments, the method may further include: f) heating the coated support in air at a temperature of from about 150 to about 500°C, such as from about 200 to about 400°C. In certain embodiments, the coated support is heated for up to about 5 hours, up to about 4 hours, up to about 3 hours, up to about 2 hours, or up to about 1 hour.

[0079] In certain embodiments, the method may further include plasma treating the support prior to coating. In particular embodiments, plasma treating the support may comprise exposing the support to a low-temperature plasma selected from oxygen plasma, argon plasma, and hydrogen plasma.

[0080] In another aspect of the invention, there is provided an electrode for an electrochemical device, the electrode comprising the catalytic composition or catalyst as disclosed hereinbefore. As details of the catalytic composition and catalyst have already been described above, they are omitted here for brevity.

[0081] In certain embodiments, the electrode may be a membrane electrode assembly. In certain embodiments, the electrochemical device may be selected from an electrolyser, a fuel cell, a battery, a supercapacitor, a photoelectrochemical cell, a flow battery, and an electrochemical sensor.

[0082] In another aspect of the invention, there is provided an electrolyser, a fuel cell, a battery, a supercapacitor, a photoelectrochemical cell, a flow battery, or an electrochemical sensor comprising the catalytic composition, catalyst, or electrode as disclosed hereinbefore. As details of the catalytic composition, catalyst and electrode have already been described above, they are omitted here for brevity.

[0083] As mentioned above, the present catalytic composition is particularly useful in producing green hydrogen via photoelectrochemical water splitting. As such, in another aspect of the invention, there is provided a method of producing hydrogen comprising contacting an aqueous electrolyte with the catalytic composition, catalyst, or electrode as disclosed hereinbefore and applying a voltage sufficient to split water into hydrogen and oxygen.

[0084] EXAMPLES Further aspects and embodiments of the invention will now be discussed by reference to the following non-limiting examples.

[0085] General Preparation Example 1

[0086] Carbon incorporated CuO solution was prepared by incorporating polyvinylidene fluoride (PVDF) polymer as the binding agent, along with a solution containing cupric oxides (CuO) and carbon black. The formulation employed a precise ratio of at the range of ~1 :1 :8 (PVDF: Carbon black: CuO). The CuO particles with size in the range of 40 nm to 60 nm. For synthesis of carbon incorporated CuO solution, PVDF of around 80 mg - 100 mg in 10 mL N-methyl-2- pyrrolidone (NMP), stirred for 1 hour followed by adding (80 mg - 100 mg) carbon black solution and 800 mg of CuO powder, stirred 12 hours, at room temperature (25°C).

[0087] General Preparation Example 2

[0088] Metal incorporated CuO composites was synthesized by incorporating CuO nanopowders with metal oxides such as aluminium oxides (AI2O3), titanium oxide (TiO2), and iron oxide (Fe20s). The amount of metal oxides was in the range of 1 % to 20% with respect to the CuO nanopowder (for AI2O3, TiO2, and Fe2Os). The size of nanoparticles was in the range of 40 nm to 80 nm. The Al- and Ti- incorporated CuO composites were prepared by using solution method as follows. PVDF of 100 mg added into 10 mL NMP and stirred for 1 hour. After that, black carbon solution of 100 mg mixed with 800 mg CuO powder and 80 mg of AI2O3 or TiO2 and stirred for 12 hours at room temperature. Furthermore, to increase the active surface area of catalysts, functionalized graphene was incorporated into the CuO composite solution. COOH functionalized graphene (G-COOH) with different concentration (1 %-10%) added into the solution.

[0089] General Preparation Example 3

[0090] Ternary alloy metal or metal oxides alloy such as NiFeCo / NiFeCoO powders mixed with carbon incorporated CuO solution and stirred for 12 hours at room temperature to achieve CuO composite with ternary metal / metal oxides. The CuO plays an important role as cocatalysts with ternary metal (oxide) such as NiFeCo(O) solution provides more active sites for electrochemical activity, reaction kinetics and stability. Its primary function is to enhance the catalytic activity of the main catalyst, NiFeCo / NiFeCoO. CuO interacts synergistically with the NeFeCo / NiFeCoO, promoting improved charge transfer kinetics and facilitating the adsorption and activation of oxygen species. This interaction results in lower overpotentials and increased overall catalytic efficiency. Composition of the CuO is in the range of 10%-50% with respect to the total mass of the composite and this can be tuned for improved efficiency of the composite catalyst. General Preparation Example 4

[0091] The as-prepared CuO solution was transferred to an acid-cleaned nickel foam electrode. To transfer the CuO solution onto the Ni foam, the Ni foam placed in the precursor solution for around 10-15 minutes to ensure homogeneous coating and then dried in vacuum oven at 50°C -100°C for removing the residual organic solvent from the Ni foam. The CuO coated Ni electrode thermally treated at the range of 300°C- 400°C in air ambient for a duration of 2 hours to improve the interface quality between Ni and catalyst.

[0092] Example 1 : Copper based oxide / carbon black / PVDF solution

[0093] (i) Effect of the introduction of CuO

[0094] To evaluate the electrocatalytic activities for HER, linear sweep voltammetry (LSV) was carried out at a scan rate of 20 mV s-1in 1 mol / L KOH solution. The corresponding metal oxides / nickel foam (NF) electrodes exhibited much enhanced catalytic activities compared with bare NF, as shown in FIG. 1 (a). The current density increased from -334 mA / cm2(C-PVDF NF) (Sample 3) to -780 mA / cm2(CuO-C-PVDF NF) (Sample 4) at a potential (V vs RHE) of -1 V. The overpotential at 100 mA / cm2of bare NF is -442 mV, while the overpotential at 100 mA / cm2of CuO-C-PVDF NF can up to be -63 mV, suggesting that the superior catalytic activities are caused by the electrocatalyst instead of NF itself. Here, C-PVDF NF as a contrast sample was tested, the overpotential at 100 mA / cm2is 649 mV. The carbon coating would alter the porous structure of the nickel foam substrate, leading to a reduction in specific volume, which could impact its performance. CuO-PVDF was also tested, and the overpotential at 100 mA / cm2is - 149 mV. Only adding CuO had limited effect on enhancing LSV performance but incorporating carbon black contributed to a dual-action effect, significantly boosting catalytic performance. CuO-C-PVDF NF stability performance under 3600s was shown in FIG. 1 (b).

[0095] Table 1 : Overpotentials (for HER) at different current densities for samples in 1 M KOH solution (ii) Impact of thermal treatment of CuO / carbon black / PVDF / nickel foam (NF) samples The LSV of CuO / carbon black / PVDF NF samples prepared under different annealing temperature was illustrated in FIG. 2. The current density increased from -418 mA / cm2(bare NF) to -607 mA / cm2(CuO-PVDF400) at (V vs RHE) -1 V. Thermal treatment has improved the catalytic activity, with the increase of annealing temperature, the overpotential at 100 mA / cm2also decreased. When the temperature was up to 500°C, the current density curve changed, and the current density is not good as that at annealing temperature of 400°C. The alterations in surface morphology due to the high temperatures has impacted the material's ability to catalyse reactions effectively, suggesting a direct correlation between structural changes and catalytic behaviour. The CuO composite annealed up to 400°C (CuO-PVDF400) can be a good candidate as electrocatalyst.

[0096] Table 2: Overpotentials (for HER) at different current densities for samples in 1 M KOH solution

[0097] (Hi) Effect of concentration of CuO

[0098] The LSV of CuO / carbon black / PVDF NF samples prepared under different concentration of CuO was illustrated in FIG. 3. The current density increased from -418 mA / cm2(bare NF) to - 618 mA / cm2(CuO-C-PVDF100), -775 mA / cm2(2CuO-C-PVDF100) (CuO concentration double) at -1 V. With the increase of the concentration of CuO, the overpotential at 100 mA / cm2decreased from -151 mV (CuO-C-PVDF100) to -88 mV (2CuO-C-PVDF100). In this regard, 2CuO-C-PVDF100 is a better candidate as electrocatalyst.

[0099] Table 3: Overpotentials (for HER) at different current densities for samples in 1 M KOH solution (iv) Effect of dipping times

[0100] The LSV of 2CuO / carbon black / PVDF NF samples with different dipping times was illustrated in FIG. 4. With the increase of dipping times, there were no obvious changes to the current density. The current density at -1 V is 418 mA / cm2(bare NF), -775 mA / cm2(2CuO-C-PVDF100, dipping 10 mins), -769 mA / cm2, (2CuO-C-PVDF100 dipping 20 mins), -770 mA / cm2(2CuO- C-PVDF400, dipping 10 mins), -761 mA / cm2(2CuO-C-PVDF400, dipping 20 mins), respectively.

[0101] Table 4: Overpotentials (for HER) at different current densities for samples in 1 M KOH solution

[0102] Example 2: CuO composites with carbon black and PVDF solution

[0103] LSV curves of CuO composites were also experimented, as shown in the FIG. 5. CuO-TiO2-

[0104] C-PVDF NF sample exhibits highest current density at -1 V, and CuO-AI-C-PVDF shows the smallest current density at -1 V.

[0105] Table 5: Overpotentials (for HER) at different current densities for samples in 1 M KOH solution

[0106] It is noted that the difference between CuO-AI-C-PVDF400 and Cu0-Al203-C-PVDF400 lies in the form and method of Al incorporation. In CuO-AI-C-PVDF400, metallic Al was used as a precursor, which undergoes in-situ oxidation during thermal treatment. This process can lead to finer dispersion, different morphologies, and even partial doping into the CuO lattice, potentially modifying its electronic structure and catalytic activity. In contrast, CuO-AI2O3-C- PVDF400 uses pre-formed AI2O3as a support material, contributing primarily through physical interaction and surface area enhancement rather than chemical modification. Therefore, using metallic Al as a precursor presents a suitable route for incorporating AI2O3into the CuO matrix with possible synergistic effects, making it important to investigate both approaches experimentally to understand their respective contributions to catalytic performance.

[0107] Example 3: CuO / graphene / carbon black / PVDF solution

[0108] (i) Effect of concentration of CuO

[0109] The LSV of CuO / graphene / carbon black / PVDF NF samples prepared under different concentration of CuO was illustrated in FIG. 6. The current density increased from -770 mA / cm2(2CuO-G-C-PVDF400) to -967 mA / cm2(3CuO-G-C-PVDF400) at -1 V. With the increase of the concentration of CuO, the overpotential at 100 mA / cm2decreased from -83 mV (2CuO-G-C-PVDF400) to -63 mV (3CuO-G-C-PVDF400). The sample of 3CuO-G-C- PVDF400 exhibit the best performance. The scanning electron microscopy (SEM) images, energy-dispersive X-ray spectroscopy (EDX) analysis and the elemental mapping analysis of 3CuO-G-C-PVDF400 are included in FIG. 7. The Cu element is evenly distributed on the surface of nickel foam. able 6: Overpotentials (for HER) at different current densities for samples in 1 M KOH solution

[0110] (ii) Effect of concentration of graphene The LSV of CuO / graphene / carbon black / PVDF NF samples prepared under different concentration of graphene was illustrated in FIG. 8. The current density is -827 mA / cm2(2CuO-G-C-PVDF400), -784 mA / cm2(2CuO-2G-C-PVDF400), -647 mA / cm2(2CuO-4G-C- PVDF400) at -1 V. The sample of 2CuO-2G-C-PVDF400 shows the lowest potential at a current density of 100 mA / cm2, it decreased from -1 12 mV (2CuO-G-C-PVDF400) to -27 mV (2CuO-2G-C-PVDF400). The sample of 2CuO-2G-C-PVDF400 exhibits the best performance.

[0111] Table 7: Overpotentials (for HER) at different current densities for samples in 1 M KOH solution

[0112] Example 4: Two electrodes test

[0113] Results of two terminal test are provided in Table 8. Compared with bare NF, when using 3CuO-G-C-PVDF as anode, a lower voltage is required for the generation of bubbles, indicating better catalytic efficiency. The sample of CuO-AI-C-PVDF exhibits great potential for electrocatalytic cathode. As a cooperation of these two samples, the bubbles on both sides come out at a potential of 2.24 V and at a current of 0.14 A. This observation suggests that the catalytic performance is enhanced by as-prepared samples, as evidenced by the lower voltage required for the initiation of bubble formation. The efficiency in catalysing the electrochemical reaction is thereby inferred to be superior under these conditions.

[0114] The CuO composite with ternary metal and metal oxides have been used to prepare anion- based membrane electrode assembly (MEA) to evaluate the performance of the catalysts. The overall current density of is around 1 Amp / cm2, evaluated using 2 cells AEM electrolyser.

[0115] Table 8: Potential and current with different electrodes samples

[0116] FIG. 10(a) depicts the current-potential (l-V) response of the 2CuO-2G-C-PVDF400 working electrode (WE) using Pt as the counter electrode (CE). This setup represents a conventional electrochemical cell configuration with a noble metal CE. FIG. 10(b) depicts the l-V response of the 2CuO-2G-C-PVDF400 working electrode using a matching 2CuO-2G-C-PVDF100 counter electrode, representing a symmetric or dual-electrode system composed entirely of non-noble, active material.

[0117] When using Pt as the CE (Fig. 10a), the system shows lower current output, likely due to a more balanced and catalytic response at both electrodes. When using the same CuO-2G-C- PVDF material for both WE and CE (Fig. 10b), the current output increases drastically, suggesting (a) higher catalytic activity or electron transfer synergy between identical material and (b) possible enhancement in redox reaction kinetics due to matched electrode surface properties and conductivity. In addition, both curves begin to rise more significantly after ~1 .5 V, indicating similar onset potentials for electrochemical activity.

[0118] The CuO-2G-C-PVDF400 electrode demonstrates promising electrochemical activity. Pairing the material as both WE and CE (Fig. 10b) offers a significant advantage in current response over the conventional Pt CE configuration (Fig. 10a). This suggests strong potential for this material combination in symmetric electrode applications, possibly in low-cost electrolyzers or electrochemical energy systems.

[0119] Example 5: FT-IR Characterization of CuO based composite catalyst

[0120] Fourier Transform Infrared (FTIR) Spectroscopy is used to identify and confirm the functional groups, chemical bonds, and molecular interactions within CuO based catalyst. FIG. 9 displays the FTIR spectra of the CuO composite catalyst, highlighting the characteristic absorption bands corresponding to its various components. Table 9 provides a detailed explanation of each peak, along with its corresponding assignment and analysis. Table 9: FTIR explanation of each peak, along with its corresponding assignment and analysis

[0121] Discussion:

[0122] To evaluate the electrocatalytic performance for hydrogen evolution reaction, various CuO- based composite catalysts were prepared on nickel foam (NF) and tested in 1 M KOH using linear sweep voltammetry. The CuO-carbon black-PVDF (CuO-C-PVDF) composite showed a significant enhancement in catalytic activity, reaching a current density of -780 mA / cm2at - 1 V vs RHE, with an overpotential of only -63 mV at 100 mA / cm2— outperforming bare NF (- 442 mV) and CuO-PVDF alone (-149 mV). Increasing CuO concentration further improved activity, with 2CuO-C-PVDF showing -88 mV overpotential, and 3CuO-G-C-PVDF reaching - 63 mV. Graphene addition enhanced performance, with 2CuO-2G-C-PVDF achieving the lowest overpotential of -27 mV. Dipping time had minimal influence, and composite catalysts containing TiO2showed superior performance among other metal oxide additives. In two- electrode testing, pairing 3CuO-G-C-PVDF as anode and CuO-AI-C-PVDF as cathode led to hydrogen evolution at 2.24 V and 0.14 A. Finally, the CuO-based composite incorporating ternary metals was integrated into an anion exchange membrane (AEM) electrolyser, demonstrating high durability and a current density of ~1 A / cm2, highlighting the catalyst’s strong potential for practical hydrogen production.

[0123] Formation of CuO composite with ternary metal alloy (Ni-Fe-Co), is also formed to evaluate hydrogen production. In comparison, the CuO-Ni-Fe-Co composite catalyst exhibited an improved performance of approximately 20% higher current, achieving a current of ~168 mA at the same applied potential (-2.24 V). This enhancement underscores the synergistic effect of the ternary alloy (Ni-Fe-Co) in promoting both hydrogen and oxygen evolution reactions, thereby increasing the overall electrocatalytic efficiency of the system.

[0124] The catalyst material is designed with careful consideration of the structural features of the Ni substrate. The presence of crevices in the Ni foam substrate is strategically utilized to facilitate the adsorption of protons on the catalyst's surface. This occurs by intentionally disrupting the hydrogen-hydrogen bonds, allowing for a more efficient interaction between the catalyst and protons. The design is particularly effective in promoting the release of hydrogen gas, a key outcome of the catalyst's function. The utilization of the crevices in the Ni foam substrate enhances the accessibility of protons to the catalyst's active sites, optimizing the overall catalytic process for hydrogen evolution. Additionally, a noteworthy aspect of the catalyst's development lies in the meticulous surface engineering of the interface between copper oxide and Ni foam during the heat treatment process in the range of 200°C-400°C in an atmospheric condition, enhancing the overall performance of the catalyst. This deliberate engineering enhances the interfacial characteristics, potentially influencing factors such as conductivity and catalytic efficiency. The careful attention to the copper oxide-Ni foam interface contributes significantly to the overall performance of the catalyst, making it more effective in facilitating the desired reactions, such as the evolution of hydrogen gas.

[0125] Charge carrier migration occurs as electrons from the electrode participate in reducing protons, ultimately resulting in the production of hydrogen gas. The swift migration of these electrons to the active sites of the catalyst is crucial for the efficient separation of charge carriers in both the OER and HER. This rapid migration process is facilitated by the functionalization of 2D materials and conductivity of the catalyst, enhancing the overall effectiveness of charge carrier separation and subsequent electrocatalytic activities in the reactions. (In the context of electrocatalysis, charge carrier migration refers to the movement of electrons from the electrode, which actively participate in the reduction of protons. This electrochemical process leads to the generation of hydrogen gas. The efficiency of this process relies on the rapid migration of these electrons to the active sites of the catalyst. To facilitate and enhance this rapid migration, the process incorporates in-situ doping of 2D materials. This deliberate introduction of dopants serves to modify their electronic properties, optimizing the movement of electrons. The in-situ doping of 2D materials contributes significantly to the overall effectiveness of charge carrier separation. By enhancing the migration of electrons to the catalyst's active sites, this doping process promotes more efficient and accelerated electrocatalytic activities. As a result, it positively influences the performance of the catalyst in both the OER and HER, contributing to the overall working of the electrochemical processes involved.)

[0126] To enhance the efficiency of the process, steps were taken to minimize the recombination of charges (electrons and protons) on the catalyst surface, through introduction of functionalized Carboxyl Graphene (G-COOH). This efficient separation of charges prevents wasteful reactions and contributes to a higher overall reaction rate. To optimize the process efficiency, measures were implemented to reduce the recombination of charges (electrons and protons) on the catalyst surface. The strategic introduction of functionalized Carboxyl Graphene ensures an effective separation of charges, preventing undesired reactions and elevating the overall reaction rate. (The use of functionalized Carboxyl Graphene serves as a key factor in fine-tuning the charge dynamics on the catalyst surface, ensuring that electrons and protons are efficiently utilized in the targeted electrochemical reactions. This not only prevents energy losses due to charge recombination but also enhances the overall efficiency of the catalytic system.)

[0127] The utilization of carbon black solution in synthesis of the present catalyst material has a twofold impact. Firstly, it promotes homogeneity in the solution by ensuring stability in the solvent. This is crucial for maintaining a uniform mixture, enhancing the overall quality of the solution. Secondly, the presence of carbon black in the solution significantly improves the conductivity of the electrode. Carbon black is known for its conductive nature, and when incorporated into the electrode material, it facilitates the efficient flow of electrical charge. This improved conductivity is beneficial for the overall performance of the electrode.

[0128] Surface engineering through plasma and heat treatment to the Ni foam substrate enhanced its mechanical properties and enabled it to withstand the corrosion which can be expected due to the aqueous working medium of the electrodes. The application of surface engineering via plasma treatment and heat treatment to the Ni foam substrate not only bolstered its mechanical properties making it robust and durable but also conferred resistance against corrosion, a common occurrence in the presence of the aqueous working medium used for the electrodes. Corrosion resistance ensures the prolonged integrity and functionality of the substrate in the electrochemical environment, contributing to the overall reliability and stability of the system.

[0129] The effective integration of all the mentioned functions plays a crucial role in fine-tuning the electrochemical properties, consequently enhancing catalytic activity in the water splitting and hydrogen generation process. This innovative approach sets the present invention apart and highlights the advantages of the present invention

[0130] CuO-based composites as co-catalysts in combination with ternary alloys such as NiFeCo and NiFeCoO are evaluated for hydrogen and oxygen generation via water electrolysis. The catalyst slurry was applied onto a nickel felt substrate using the decal transfer method and dried at 80°C. The catalyst loading in membrane electrode assemblies (MEAs) is being investigated across a range of 3-25 mg / cm2, with CuO content optimized between 5-30% with 15 mg / cm2identified as an optimal loading for electrochemical evaluation. These configurations are being developed using a catalyst-coated membrane (CCM) approach tailored for anion exchange membrane (AEM) electrolyser systems.

[0131] Electrochemical measurements were conducted in a two-electrode configuration using 1 M KOH as the electrolyte. The prepared electrode served as the working electrode, and a Ni mesh was employed as the counter electrode. The linear sweep voltammetry (LSV) results demonstrated an onset potential of approximately 1 .45 V versus RHE and an overpotential of -220 mV at 100 mA / cm2current density.

[0132] The CuO based catalyst composition was successfully scaled up for practical application in an anion exchange membrane (AEM) electrolyser system. The scaling process involved synthesizing the catalyst in batch volumes of at least 500 mL, using one of the high-boiling- point organic solvents such as N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), or cyclohexane to ensure homogeneous dispersion of the carbon black and CuO nanoparticles within the PVDF binder matrix. The scaled-up catalyst slurry was then applied onto a large- area nickel foam substrate measuring 6 cm x 6 cm, suitable for integration into a laboratoryscale AEM electrolyser. The coating was performed via spray-coating, followed by vacuum drying and thermal treatment as previously described. The electrodes were assembled into a two-cell AEM electrolyser system, each with an active area of 6 cm x 6 cm, and operated using a commercial AEM and an alkaline electrolyte (e.g., 1 M KOH). Performance testing of the system was carried out at current densities exceeding 500 mA / cm2, demonstrating the catalyst's ability to support high-rate hydrogen evolution and oxygen evolution reactions under industrially relevant conditions. The system showed stable electrochemical performance for over 100 continuous hours, with minimal degradation in overpotential and cell efficiency, thereby validating the catalyst’s scalability and durability. This configuration highlights the practical applicability of the catalyst in modular, stackable electrolyzer systems designed for green hydrogen production. The system can be further expanded into larger stacks by replicating the 6x6 cm cell design, demonstrating the feasibility of scale-up from laboratory to pilot-scale systems.

Claims

1. CLAIMS1 . A catalytic composition, the catalytic composition comprising: copper oxide nanoparticles; carbon black; and a binder.

2. The catalytic composition according to Claim 1 , wherein the composition comprises from about 5wt% to about 60wt% copper oxide nanoparticles, such as about 7wt% to about 55wt% copper oxide nanoparticles, such as about 10wt% to about 50wt% copper oxide nanoparticles.

3. The catalytic composition according to Claim 1 or Claim 2, wherein the copper oxide nanoparticles have a diameter of from about 20 nm to about 80 nm, such as about 30 nm to about 70 nm, such as about 35 nm to about 65 nm, such as about 40 nm to about 60 nm.

4. The catalytic composition according to any preceding claim, wherein the copper oxide nanoparticles are cupric oxide (CuO) nanoparticles.

5. The catalytic composition according to any preceding claim, wherein the composition comprises from about 1wt% to about 40wt% carbon black, such as from about 2wt% to about 35wt% carbon black, such as from about 5wt% to about 30wt% carbon black.

6. The catalytic composition according to any preceding claim, wherein the composition comprises from about 1 wt% to about 10wt% binder.

7. The catalytic composition according to any preceding claim, wherein the binder is selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), an anion- exchange ionomer (e.g., Sustainion®), polybenzimidazole (PBI), polyurethane, an epoxy resin, polysulfone, polyether ether ketone (PEEK), polyacrylic acid (PAA), polyvinyl alcohol (PVA) or a combination thereof.

8. The catalytic composition according to any preceding claim, wherein the catalytic composition further comprises one or more metal oxides, optionally wherein the metal oxide is one or more of aluminium oxide (AI2O3), titanium oxide (TiO2), and iron (III) oxide (Fe2O3), cerium oxide (CeO2), zirconium oxide (ZrO2), manganese oxide (MnO2or Mn2O3), cobalt oxide (Co304), nickel oxide (NiO), tin oxide (SnO2), indium-tin oxide (ITO), silica (SiO2), zincoxide (ZnO), and vanadium oxide (V2O5), further optionally wherein the metal oxide is one or more of AI2O3, TiO2, and Fe2O3.

9. The catalytic composition according to Claim 8, wherein the composition comprises from about 0.1 wt% to about 25wt% of the one or more metal oxides with respect to the copper oxide nanoparticles, such as about 0.5wt% to about 22wt% of the one or more metal oxides, such as about 1wt% to about 20wt% of the one or more metal oxides.

10. The catalytic composition according to any preceding claim, wherein the composition further comprises a co-catalyst.

11. The catalytic composition according to Claim 10, wherein the co-catalyst comprises one or both of a metal alloy and a metal alloy oxide.

12. The catalytic composition according to Claim 1 1 , wherein the metal alloy or metal alloy oxide is a ternary metal alloy or ternary metal alloy oxide.

13. The catalytic composition according to Claim 12, wherein the ternary metal alloy or the ternary metal alloy oxide comprises metals selected from nickel, iron, molybdenum, manganese, tungsten, copper and cobalt, optionally wherein the ternary metal alloy or the ternary metal alloy oxide comprises nickel-iron-molybdenum, nickel-iron-manganese, nickel-iron-tungsten, cobalt-manganese-iron, nickel-cobalt-molybdenum, or nickelcopper-iron.

14. The catalytic composition according to any preceding claim, wherein the composition further comprises graphene, optionally wherein the graphene is functionalised, optionally wherein the functionalised graphene comprises carboxyl graphene.

15. The catalytic composition according to Claim 14, wherein the composition comprises from about 0.1 wt% to about 15wt% graphene, such as from about 0.5wt% to about 12wt% graphene, such as from about 1wt% to about 10wt% graphene.

16. The catalytic composition according to any preceding claim, wherein the ratio of copper oxide nanoparticles to the carbon black is from about 1 :1 to about 4:1 , such as about 2:1 to about 3:1 (wt:wt).

17. A catalyst comprising the catalytic composition according to any of Claims 1 to 16 provided on a support, optionally wherein the support is a metal foam support, optionally a nickel metal foam support.

18. The catalyst according to Claim 17, wherein the catalyst exhibits an overpotential of less than 300 mV at 100 mA / cm2in 1 M KOH.

19. A method of preparing a catalytic composition, the method comprising: a) providing a binder in a solvent to provide a binder mixture; b) incorporating carbon black into the binder mixture; c) incorporating copper oxide nanoparticles into the binder mixture; and d) stirring the mixture to form a composite material of the binder, carbon black, and copper oxide nanoparticles.

20. The method according to Claim 19, wherein the method further comprises incorporating graphene such that the graphene is incorporated into the composite material.21 . The method according to Claim 19 or Claim 20, wherein the solvent is selected from one or more of NMP, DMF, and cyclohexane.

22. The method according to any of Claims 19 to 21 , wherein the method further includes incorporating one or more metal oxides, such as one or more of aluminium oxide (AI2O3), titanium oxide (TiO2), and iron (III) oxide (Fe2O3) cerium oxide (CeO2), zirconium oxide (ZrO2), manganese oxide (MnO2or Mn2O3), cobalt oxide (Co3O4), nickel oxide (NiO), tin oxide (SnO2), indium-tin oxide (ITO), silica (SiO2), zinc oxide (ZnO), and vanadium oxide (V2O5), such as one or more of AI2O3, TiO2, and Fe2Os, into the binder mixture.

23. The method according to any of Claims 19 to 22, wherein the method further includes incorporating a co-catalyst into the binder mixture, optionally wherein the co-catalyst comprises one or both of a metal alloy and a metal alloy oxide, optionally wherein the metal alloy or metal alloy oxide is a ternary metal alloy or ternary metal alloy oxide, optionally wherein the ternary metal alloy or the ternary metal alloy oxide comprises metals selected from nickel, iron, molybdenum, manganese, tungsten, copper and cobalt, optionally wherein the ternary metal alloy or the ternary metal alloy oxide comprises nickel-iron-molybdenum, nickel-iron- manganese, nickel-iron-tungsten, cobalt-manganese-iron, nickel-cobalt-molybdenum, or nickel-copper-iron.optionally wherein the ternary metal alloy or the ternary metal alloy oxide comprises nickel- iron-molybdenum, nickel-iron-manganese, nickel-iron-tungsten, cobalt-manganese-iron, nickel-cobalt-molybdenum, or nickel-copper-iron.

24. The method according to any of Claims 19 to 23, wherein the method further includes: e) coating a support with the binder mixture to provide a coated support.

25. The method according to Claim 24, wherein the method further includes: f) heating the coated support in air at a temperature of from about 150 to about 500°C, such as from about 200 to about 400°C, optionally wherein the coated support is heated for up to about 5 hours, up to about 4 hours, up to about 3 hours, up to about 2 hours, or up to about 1 hour.

26. The method according to Claim 24 or Claim 25, wherein the method further includes plasma treating the support prior to coating, optionally wherein plasma treating the support comprises exposing the support to a low-temperature plasma selected from oxygen plasma, argon plasma, and hydrogen plasma.

27. An electrode for an electrochemical device, the electrode comprising the catalytic composition or catalyst according to any of Claims 1 to 18, optionally wherein the electrode is a membrane electrode assembly, optionally wherein the electrochemical device is selected from an electrolyser, a fuel cell, a battery, a supercapacitor, a photoelectrochemical cell, a flow battery, and an electrochemical sensor.

28. An electrochemical device comprising the catalytic composition, catalyst, or electrode according to any of Claims 1 to 18, and 27, optionally wherein the electrochemical device is selected from an electrolyser, a fuel cell, a battery, a supercapacitor, a photoelectrochemical cell, a flow battery, and an electrochemical sensor, preferably an electrolyser.

29. A method of producing hydrogen comprising contacting an aqueous electrolyte with the catalytic composition, catalyst, or electrode according to any of Claims 1 to 18 and 27, and applying a voltage sufficient to split water into hydrogen and oxygen.

30. Use of the catalytic composition, catalyst, electrode, or electrolyser according to any of Claims 1 to 18, 27, and 28 for generating hydrogen.

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