CN118339327A

CN118339327A - Electrolytic cell electrocatalyst comprising cobalt (Co) oxide, zirconium (Zr) and a noble metal, electrode comprising the electrocatalyst and use of the electrocatalyst in an electrolytic process

Info

Publication number: CN118339327A
Application number: CN202280058905.7A
Authority: CN
Inventors: 约翰尼斯·霍德弗里德·福斯
Original assignee: Magneto Special Anodes BV
Current assignee: Magneto Special Anodes BV
Priority date: 2021-09-13
Filing date: 2022-09-13
Publication date: 2024-07-12

Abstract

An electrolyser electrocatalyst comprising cobalt (Co) oxide, zirconium (Zr) and a noble metal; an electrode for an electrolytic cell, the electrode comprising a support and a coating comprising the electrocatalyst; an electrochemical system comprising an electrolysis cell having an electrode comprising the electrocatalyst; the use of the electrocatalyst for catalyzing an electrolysis process; a method of electrolyzing water using the electrocatalyst; and a method for producing an electrode comprising the electrocatalyst.

Description

Electrolytic cell electrocatalyst comprising cobalt (Co) oxide, zirconium (Zr) and a noble metal, electrode comprising the electrocatalyst and use of the electrocatalyst in an electrolytic process

Electrolysis is a promising option for carbon-free hydrogen production from renewable and nuclear resources. Electrolysis is a process of decomposing water into hydrogen and oxygen using electricity. The process of electrolysis is carried out in a unit called an electrolyzer. The size of the electrolyzer can range from small electrical devices well suited for small scale distributed hydrogen production to large scale central production facilities, which can be connected directly to renewable or other forms of electricity production that do not emit greenhouse gases, for example.

Technical Field

In 2021, the U.S. department of energy (DOE) has established a goal to reduce the cost of cleaning hydrogen by 80% to $ 1 per 1 kg within 10 years. The goal of reducing hydrogen production to $ 1 per 1 kg within 10 years is called the hydrogen "11 1" initiative. Electrolysis is the primary hydrogen production pathway to achieve this goal.

Hydrogen produced via electrolysis can lead to zero greenhouse gas emissions, depending on the source of the electricity used. When assessing the benefits and economic viability of hydrogen production via electrolysis, it is necessary to consider the source of the electricity required, including its cost and efficiency, as well as emissions caused by electricity generation. In many parts of the world, today's power grid is not ideal for providing the power required for electrolysis. The reason for this is the greenhouse gases released during the actual power generation and the amount of fuel required to generate power due to the inefficiency of the power generation process.

Hydrogen production via electrolysis is being used for renewable energy and nuclear energy options including wind, solar, water and geothermal energy production. These approaches result in almost zero greenhouse gas and standard pollutant emissions as long as the electricity for electrolysis is obtained from renewable energy sources. Furthermore, it is important that the overall production costs of the energy source be significantly reduced to compete with more sophisticated carbon-based pathways such as natural gas reforming.

In view of the foregoing, there is an increasing need for improved electrolytic cells that exhibit improved energy efficiency and life. In particular, there appears to be a need to provide improved coatings for electrodes used in electrolytic cells, such as improved coatings for oxygen evolution as a target reaction.

Summary of The Invention

According to a first aspect, the present disclosure relates to an electrolyser electrocatalyst comprising cobalt (Co) oxide, zirconium (Zr) and a noble metal.

According to a second aspect, the present disclosure relates to an electrode for an electrolytic cell, the electrode comprising a support and a coating, wherein the coating comprises cobalt (Co) oxide, zirconium (Zr) and a noble metal.

According to a third aspect, the present disclosure relates to an electrochemical system comprising an electrolysis cell having a cathode, an anode, and one or more electrolytes, wherein the cathode, the anode, or both the cathode and the anode comprise an electrocatalyst comprising cobalt (Co) oxide, zirconium (Zr), and a noble metal.

According to a fourth aspect, the present disclosure relates to the use of an electrocatalyst for catalytic electrolysis processes, wherein the electrocatalyst comprises cobalt (Co) oxide, zirconium (Zr) and a noble metal.

According to a fifth aspect, the present disclosure relates to a method for electrolysis of water, comprising the steps of:

(i) Providing a water electrolyzer comprising an anode, a cathode, and one or more electrolytes, wherein at least one of the anode and the cathode comprises an electrocatalyst comprising cobalt (Co) oxide, zirconium (Zr), and a noble metal;

(ii) Contacting the water cell with water;

(iii) Creating an electrical bias between the cathode and the anode; and

(Iv) Hydrogen and/or oxygen is produced.

According to a sixth aspect, the present invention relates to the use of a cathodic electrocatalyst comprising cobalt (Co) oxide, zirconium (Zr) and a noble metal for the production of hydrogen via an electrolysis process.

According to a seventh aspect, the present disclosure relates to a method for producing an electrode for an electrolytic cell, the electrode comprising a support and a coating, the method comprising the steps of:

Preparing a metal support comprising nickel (Ni) or titanium (Ti),

-Applying a coating comprising cobalt (Co), zirconium (Zr) and a noble metal on a support, and

-Heating the support comprising the coating in air.

Brief Description of Drawings

Fig. 1 shows an exemplary embodiment of an electrolytic cell 10 according to the prior art;

FIG. 2 graphically illustrates the effect of adding zirconium and ruthenium to cobalt oxide coatings on the initial potential (E _i) of the coated electrode;

FIG. 3 provides a comparison between the lifetime of a cobalt oxide coating, shown in units of total charge per surface area passed (kAh/m ²) before coating deactivation, and the cobalt loading in the coating;

FIGS. 4a and 4b illustrate the lifetime and initial potential, respectively, of a cobalt oxide coating having a fixed cobalt/ruthenium mass ratio and varying zirconium mass fraction;

FIGS. 5a and 5b graphically illustrate the relationship between lifetime and initial potential of cobalt oxide coatings with a fixed cobalt/zirconium ratio and increased ruthenium loading;

FIG. 6a shows the results of a short-term electrolysis experiment run at 10kA/m ² for nickel plates and titanium and nickel supports containing cobalt/zirconium/ruthenium coatings, respectively;

FIG. 6b shows the relative wear rates of cobalt and zirconium measured on Co/Zr/Ru coatings on titanium supports;

FIG. 7 shows the results of measurements in KOH 30% at a temperature of 20℃using a nickel plate and nickel and titanium support electrodes, both provided with Co-Zr/Ru coatings 100-9/1;

FIG. 8 shows the results of a test run to evaluate the effect of using a cobalt oxide coating comprising zirconium as a dispersant along with gold (Au) to promote conductivity throughout the bulk coating; and

Fig. 9 shows the results of a test run to evaluate the effect of using a cobalt oxide coating comprising Au on activity.

Detailed Description

The phraseology and terminology used in the present disclosure is for the purpose of description and should not be regarded as limiting. As used herein, the term "more than one (plurality)" refers to two or more items or components. The terms "comprising," "including," "carrying," "having," "containing," and "involving (involving), whether in the written description or the claims and the like, are open-ended terms that mean" including but not limited to. Accordingly, the use of such terms is intended to encompass the items listed thereafter and equivalents thereof as well as additional items. With respect to the claims, only the transitional phrases "consisting of" and "consisting essentially of" are closed transitional phrases or semi-closed transitional phrases, respectively. The use of ordinal terms such as "first," "second," "third," and the like in the claims to modify a claim element does not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a certain name from another element having a same name (but for use of the ordinal term) to distinguish the claim elements.

Hydrogen (H ₂) is an important feedstock (feed stock) for various branches of the chemical industry such as petrochemical and semiconductor manufacturing. In addition, it has great potential as a vehicle (agent) that makes global energy infrastructure more environmentally sustainable. In hydrogen economy, hydrogen can be used as an energy carrier to replace fossil fuels and also to reduce CO ₂ emissions in energy intensive applications such as steel and aluminum refining.

The most prominent way to produce truly "green" hydrogen is by water electrolysis driven by renewable energy sources. However, water electrolysis has a problem of low energy efficiency due to difficulty in catalyzing the reaction. Better electrocatalysts are needed to make the process more economically competitive.

The overall reaction in water electrolysis is given by

2H₂O→2H₂+O₂。

The process is carried out in an acid or alkaline cell, wherein the acid cell uses a wet acid ion exchange membrane as electrolyte and the alkaline cell uses a concentrated aqueous base, typically KOH in the range of 15-30% by mass, and Zirfon separators as electrolyte.

Acidic systems benefit from compactness, low electrolyte resistance and good gas separation capacity, which allows them to operate at higher current densities, typically 10kA/m ²-30 kA/m², and makes them more flexible in terms of ramp-up and ramp-down activity. One of the main drawbacks is that this type of electrolyzer relies on iridium as the electrocatalyst on the anode, which is a very rare and therefore expensive element. Alkaline systems rely much less on critical materials, but are more bulky, with higher internal resistance and lower power flexibility.

The overall reaction consists of two electrochemical half reactions, namely Hydrogen Evolution (HER) and Oxygen Evolution (OER), which are described in the acidic and alkaline electrolytes by:

4H⁺+4e^-→2H₂

4H₂O+4e^-→2H₂+4OH^-

2H₂O→O₂+4H⁺+4e^-

4OH^-→O₂+2H₂O+4e^-。

The greatest energy loss comes from the oxygen evolving anode half reaction. A better electrocatalyst for this reaction will have a smaller overpotential and higher energy efficiency. In the present disclosure, an electrode comprising an improved electrocatalyst is presented.

Fig. 1 shows an exemplary embodiment of an electrolytic cell 10 to explain the basic principles of electrolysis. The electrolytic cell 10 comprises a container 11, the container 11 having a liquid alkaline solution of sodium hydroxide or potassium hydroxide as electrolyte 12.

The cell 10 further comprises an anode 21 and a cathode 22 disposed in the electrolyte 12. Anode 21 and cathode 22 are connected to an electrical energy source 30. In the electrolytic cell 10, the diaphragm 13 is positioned between the anode 21 and the cathode 22.

As shown in fig. 1, in general, the alkaline electrolyzer operates via the transport of hydroxide ions (OH ^-) through the electrolyte from the cathode 22 to the anode 21. The oxygen gas is deposited on the anode 21 side by reference numeral 41. The generation of hydrogen gas at the cathode 22 side is indicated by reference numeral 42.

Electrolytic cells using liquid alkaline solutions of sodium hydroxide or potassium hydroxide as electrolyte have been commercially available for many years. An important parameter for alkaline hydrolysis is the type of electrode and coating used. The precipitation of oxygen in alkaline water baths is usually catalysed on anodes made of bulk nickel, bulk steel or nickel coated steel. While these materials provide long life, the overpotential for oxygen evolution is relatively high. One of its effects is a relatively high level of corrosion, for example for steel-based anodes. The specifics of this corrosion are not well understood at present. The anode 21 and cathode 22 used in the cell 10 typically include suitable coatings to enhance the life of the electrodes in view of corrosion protection.

In the prior art, alternative solutions for producing electrolytic cells are known, which use a solid Alkaline Exchange Membrane (AEM) as electrolyte. Such anion exchange membranes can be used as additional electrolytes with pure water or KOH solution.

These alternative solutions using anion exchange membranes to separate the anode compartment and the cathode compartment show promise on a laboratory scale.

The present disclosure relates to electrocatalysts for electrodes, particularly anodes 21, in the form of coatings that may improve the properties of the electrodes, and particularly the lifetime of the electrodes. Coatings according to the present disclosure involve oxygen evolution as a target reaction. The coating is a cobalt (Co) oxide based coating comprising zirconium (Zr) as a dispersant and a noble metal to promote the electrical conductivity of the overall bulk coating. According to the present disclosure, the noble metal is preferably selected from ruthenium (Ru), gold (Au), iridium (Ir), platinum (Pt) and palladium (Pd). It has been determined that the lifetime of coatings comprising cobalt oxide, zirconium, and in particular ruthenium and/or gold, is much higher than known coatings, as described in more detail below. The coatings described in this disclosure provide a longer lifetime than other well known Ni alternatives such as Ni-Fe oxyhydroxide due to the much higher robustness of cobalt oxides.

In one embodiment, due to the relatively high electrochemical activity of cobalt, an anode comprising a cobalt oxide coating comprising Zr and Ru and/or Au allows for catalyzing oxygen evolution at lower overpotential and benefits from incorporation of Zr and Ru and/or Au as dispersants to promote conductivity of the overall bulk coating.

According to the present disclosure, a coating comprising cobalt oxide, zirconium and a noble metal such as ruthenium or gold is mentioned deposited on a suitable metal support. Preferably, the coating is deposited on a titanium (Ti) support or a nickel (Ni) support. Alternatively, the carrier comprises titanium alloy, nickel alloy, steel or stainless steel.

Titanium is a particularly attractive substrate because of its dimensional stability and high availability. A known disadvantage of using titanium as a support material for obtaining the electrode is the possibility of forming an electrically insulating oxide interlayer during the coating preparation or actual electrolysis. However, according to the present disclosure, the risk of forming such an electrically insulating oxide interlayer is offset by the presence of Ru in the coating, which has the ability to form an anti-passivation interlayer at the interfacial titanium-coating.

Nickel is particularly suitable for the preparation of electrodes because it is dimensionally stable and is capable of strongly interacting with Co by forming NiCo ₂O₄ spinel.

Cobalt oxide (Co ₃O₄) is a well known oxygen evolution electrocatalyst and, together with a mixture of nickel and cobalt iron oxides, is one of the materials with the highest power efficiency. This means that the material allows a low overpotential in use. This material has a lower overpotential than nickel oxide grown on bulk Ni, which is the standard material in today's alkaline cells, and tends to deactivate over time.

In order to use a Co ₃O₄ layer in an alkaline cell, a considerable layer thickness needs to be deposited; while cobalt wear rates during operation were found to be on the same scale as iridium oxide, a prior art electrocatalyst with very high rarity and price, the extremely high lifetime requirements of alkaline cells require significant loadings. However, co ₃O₄ has poor bulk conductivity, which makes a thick layer of preformed oxide impractical.

In one embodiment, an attempt to circumvent this problem is achieved by adding both a) Zr and b) Ru or Au to the Co ₃O₄ layer, which act as a) dispersants to increase the volume and active surface area of the electrocatalyst, and b) conductive agents to improve conductivity in the bulk coating and prevent the formation of passivation layers at the interface of the coating and bulk metal support during repeated calcination in air and electrolysis operations of the coating.

In accordance with the present disclosure, it has been demonstrated that, surprisingly, the combination of very small amounts of zirconium and very small amounts of noble metals such as ruthenium or gold significantly alters and improves the properties of a coating comprising cobalt oxide constituting the coating, especially when oxygen evolution is considered.

It should be noted that the coating according to the present disclosure allows to use electrodes, and in particular electrolytic cells provided with anodes of the coating, to operate with higher power efficiency. Power efficiency is a key factor in determining OPEX, which term refers to operating costs. If the gain in efficiency at high current densities is sufficient, it may also reduce the required stack size, thereby reducing CAPEX, a term referred to as capital expenditure.

Fig. 2 and 3 illustrate the beneficial effect of including zirconium and ruthenium in cobalt oxide on oxygen evolution electrocatalysis.

Fig. 2 illustrates the effect of adding zirconium and ruthenium to a cobalt oxide coating on the initial potential (E _i), shown on the Y-axis (E _i). The cobalt loading of the coating is shown on the X-axis. Fig. 2 relates to the application of a cobalt oxide coating on a titanium support.

Fig. 2 first shows the relationship between cobalt loading of pure Co ₃O₄ deposited on a titanium support and initial potential (E _i). As shown in fig. 2, the electrode potential of pure Co ₃O₄ deposited on titanium gradually increased as a function of cobalt loading.

As further shown in fig. 2, the addition of zirconium alone reduced the electrode potential at low cobalt loadings, but as the cobalt loading increased, resulting in a sharp rise in potential. Figure 2 clearly shows that the addition of a small amount of ruthenium in addition to zirconium significantly reduced the electrode potential throughout the range of low to high cobalt loadings.

In the example of fig. 2, ruthenium is present in the order of 5% by mass with respect to cobalt. This means that 0.05 g ruthenium was present per g cobalt in the coating. In view of the price of ruthenium, it is important to note that very small amounts of ruthenium have shown a beneficial effect on the properties of the coating.

Fig. 3 provides a comparison between the lifetime of a cobalt oxide coating on the Y-axis, shown in units of total charge per surface area passed (kAh/m ²) before coating deactivation, and the cobalt loading in the coating on the X-axis. Fig. 3 shows the effect of adding zirconium to the coating and the effect of adding both zirconium and ruthenium to the coating. Fig. 3 relates to the application of a cobalt oxide coating applied to a titanium support.

According to fig. 3, a coating of pure Co ₃O₄ deposited on titanium shows a linear increase in coating lifetime as a function of cobalt loading. Fig. 3 also shows that the addition of zirconium has a beneficial effect on the lifetime of the coating, and that at low cobalt loadings, the addition of zirconium significantly increases lifetime. Coatings comprising zirconium show a linear trend of increased lifetime associated with increased cobalt loading, but at higher cobalt loadings the beneficial effects fade away.

Fig. 3 finally shows that at lower cobalt loadings, further addition of ruthenium resulted in an increase in the lifetime of the coating compared to a coating comprising zirconium alone. However, coatings comprising both zirconium and ruthenium show a sustained and linear increase in lifetime with increasing cobalt loading. In the example of fig. 3, a small amount of ruthenium, on the order of 5% by mass relative to cobalt, is used to obtain the beneficial effects shown. As shown, the coating comprising ruthenium had a similar effect at lower cobalt loadings as the coating comprising zirconium alone, but the effect was no longer limited to lower cobalt loadings.

It should be noted that the results shown in fig. 2 and 3 were obtained using electrodes with cobalt oxide coatings formed by spin coating an aqueous-based solution of a metal salt precursor onto a titanium support. These titanium supports were etched beforehand in hydrochloric acid (HCl).

In general, the coating may be applied to the support. According to an embodiment, a viscosity modifier is added prior to the step of applying the coating. A suitable viscosity modifier for producing an electrode in accordance with the present disclosure is polyethylene glycol.

After the coating has been applied to the support, the production process is followed by thermal decomposition in air at 400 ℃ for 15 minutes. This means heating the titanium support in an oven. The mentioned heating step may be carried out at a temperature of between about 300 ℃ and 600 ℃, preferably between about 350 ℃ and 450 ℃.

The metal salts mentioned above may for example include CoCl ₂、RuCl₃ and ZrCl ₂. Alternatively, the salts may include Co (NO ₃)₂、Zr(NO₃)₂ and Ru (No) (NO ₃).

The electrode thus obtained was then electrolyzed in a strong acid (H ₂SO₄; 25%) at 600A/m ². Although the coating is intended to be used under strongly alkaline conditions, electrolysis in strong acids is used as an accelerated lifetime test, since one of the main degradation mechanisms is the local acidification at the catalyst surface due to the nature of the oxygen evolution reaction.

The dispersion effect of zirconium and the conductivity promoting effect of ruthenium were further analyzed, their fractions were changed, and the effect on the initial potential and the lifetime of the coating were noted.

Fig. 4a and 4b illustrate the lifetime and initial potential, respectively, of a cobalt oxide coating having a fixed cobalt/ruthenium mass ratio and varying zirconium mass fraction. In the examples of fig. 4a and 4b, the mass ratio cobalt/ruthenium is equal to 20. This means that the coating contains 0.05 g ruthenium per g cobalt. For the examples of fig. 4a and 4b, the cobalt loading of the coating was about 2.1g/m ² for each sample. It should also be noted that in the examples of fig. 4a and 4b, the coating is applied on a titanium support.

Fig. 4a shows that the addition of zirconium increases the lifetime until the mass fraction of zirconium/cobalt is about 25%. A further increase in zirconium up to 50% zirconium/cobalt mass fraction indicates a decrease in coating lifetime.

Fig. 4b shows that an increase in the mass fraction of zirconium above about 5% has no significant positive effect on the initial potential, provided that ruthenium is also present in the coating in addition to zirconium, as is the case in the example of fig. 4 b.

Fig. 5a and 5b graphically illustrate the relationship between lifetime and initial potential of cobalt oxide coatings with a fixed cobalt/zirconium ratio and increased ruthenium loading. In the examples of fig. 5a and 5b, the cobalt/zirconium mass ratio is equal to 10, which means that there is 0.1 gram of zirconium per gram of cobalt. It should also be noted that for the examples of fig. 5a and 5b, the cobalt loading was about 2.3g/m ². For the examples of fig. 4a and 4b, the coating is applied on a titanium support.

Fig. 5a shows that the addition of ruthenium in excess of a minimum of 2.5% of the mass of cobalt does not have a significant effect on the lifetime of the coating. The reason for this may be the presence of a small amount of ruthenium in the coating compared to the amount of cobalt.

Fig. 5b shows that an increased ruthenium/cobalt fraction results in a lower potential. The reason for this phenomenon may be because RuO ₂ (itself an effective oxygen evolution catalyst) itself begins to participate in the reaction. The potential benefits are already apparent at very small ruthenium concentrations. For reference, a comparative sample of pure RuO ₂ at loading is shown.

Fig. 6a shows the results of short-term electrolysis experiments run at 10kA/m ² on nickel plates and respectively titanium and nickel supports comprising cobalt/zirconium/ruthenium coatings, with a cobalt/zirconium mass ratio equal to 10 and a cobalt/ruthenium mass ratio equal to 80. The cobalt loading of the coating in fig. 6a was about 3.5 g/m ². FIG. 6a shows that the support with Co/Zr/Ru coating has a lower (over) potential than pure Ni.

FIG. 6b shows the relative wear rates of cobalt and zirconium measured on Co/Zr/Ru coatings on titanium supports. The relevant cobalt loading of fig. 6b is about 10 grams/m ².

The experiment shown in FIG. 6b was run at 50℃in KOH 30%.

FIG. 7 shows the results of measurements in KOH 30% at a temperature of 20℃using a nickel plate and nickel and titanium support electrodes, both of which are provided with Co-Zr/Ru coatings 100-9/1. Since nickel is susceptible to acid, these tests are limited to only 30% KOH electrolyte. The Y-axis of fig. 7 shows the current density.

The Co-Zr/Ru 100-9/1 coating showed a significant activity enhancement of the nickel support electrode when compared to pure nickel, however the benefits were not as high as on the titanium support electrode.

The difference in effectiveness between the coating present on the nickel support and on the titanium support may be the fact that the ruthenium component is less effective in promoting conductivity when the substrate is nickel rather than titanium. Short term stability is sufficient for both substrates.

It should also be noted that the data shown in FIG. 7 were recorded using cyclic voltammetry at a scan rate of 10mVs ^-1.

Fig. 8 shows the results of tests run to evaluate the effect of using cobalt oxide coatings containing zirconium as a dispersant along with gold (Au) to promote conductivity throughout the bulk coating. The efficiency of the life enhancing effect of four different coatings was tested separately on titanium support electrodes:

1) Pure cobalt oxide (Co ₃O₄);

2) Cobalt oxide coating (Co ₃O₄ -AU) comprising gold;

3) Cobalt oxide coating (Co ₃O₄-ZrO₂/Au) comprising zirconium and gold; and

4) Cobalt oxide coating (Co ₃O₄-ZrO₂/RuO₂) comprising zirconium and ruthenium.

According to the test presented in fig. 8, instead of using ruthenium as a promoter, gold was incorporated into the coating.

As shown in fig. 8, the presence of gold in the cobalt oxide coating was found to have a beneficial effect on the lifetime of the coating, provided that the coating also contained zirconium as a dispersant.

The coating shown in fig. 8 has a cobalt/gold mass ratio of 200.

The data provided in FIG. 8 for cobalt oxide coatings comprising zirconium and ruthenium are related to Co-ZR/RUl 100-9/1 electrodes and are shown in FIG. 8 as references. The lifetime in the accelerated lifetime test in H ₂SO₄% was also improved relative to pure cobalt oxide, but only when ZrO ₂ was also included. From the characterization cyclic voltammograms, it appears similar to ruthenium that inclusion of gold promotes the conductivity of the coating.

Fig. 9 shows the results of a test run to evaluate the effect of using a cobalt oxide coating comprising Au on activity. The effect of Au on activity was also tested in KOH 30% electrolyte using cyclic voltammetry at 20 ℃. Although Co-Au coatings provide higher activity than pure nickel, the enhancement is not as great as Co/Zr/Ru coatings.

Claims

1. An electrolytic cell electrocatalyst comprising cobalt (Co) oxide, zirconium (Zr) and a noble metal.

2. The electrocatalyst according to claim 1, wherein said noble metal is selected from ruthenium (Ru), gold (Au), iridium (Ir), platinum (Pt) and palladium (Pd).

3. The electrocatalyst according to claim 1, wherein said noble metal is selected from ruthenium (Ru) and gold (Au).

4. An electrocatalyst according to claim 1,2 or 3, wherein the mass fraction of zirconium relative to cobalt (Co) is from about 2% to 20%, preferably from 5% to 15%, more preferably from 10% to 15%.

5. The electrocatalyst according to claim 1, 2, 3 or 4, wherein the mass fraction of noble metal relative to cobalt (Co) is from about 0.5% to 20%, preferably from 2% to 15%, more preferably from 5% to 10%.

6. The electrocatalyst according to one of claims 1 to 5, which is an anode electrocatalyst or a cathode electrocatalyst.

7. An electrode for an electrolytic cell, the electrode comprising a support and a coating, wherein the coating comprises cobalt (Co) oxide, zirconium (Zr), and a noble metal.

8. The electrode of claim 7, wherein the carrier comprises nickel (Ni) or a nickel alloy.

9. The electrode of claim 7, wherein the support comprises titanium (Ti) or a titanium alloy.

10. The electrode of claim 7, wherein the carrier comprises steel or stainless steel.

11. The electrode of claim 8, 9 or 10, wherein the noble metal is selected from ruthenium (Ru) and gold (Au).

12. The electrode according to one of claims 8-11, wherein the mass fraction of zirconium relative to cobalt (Co) is about 2% -20%, preferably 5% -15%, more preferably 10% -15%.

13. The electrode according to one of claims 8-12, wherein the mass fraction of the noble metal relative to cobalt (Co) is about 0.5-20%, preferably 2-15%, more preferably 5-10%.

14. The electrode of any one of claims 8-13, wherein the cobalt (Co) loading in the coating is about 2g/m ²-25 g/m², preferably 5g/m ²-10 g/m².

15. An electrochemical system comprising an electrolysis cell having a cathode, an anode, and one or more electrolytes, wherein the cathode, the anode, or both the cathode and the anode comprise an electrocatalyst comprising cobalt (Co) oxide, zirconium (Zr), and a noble metal.

16. The electrochemical system of claim 15, wherein the electrolysis system is a water electrolysis cell.

17. Use of an electrocatalyst for catalytic electrolysis process, wherein the electrocatalyst comprises cobalt (Co) oxide, zirconium (Zr) and a noble metal.

18. Use according to claim 17, wherein the electrolysis process is electrolysis of water.

19. Use according to claim 17 or 18, wherein the electrocatalyst is part of a cathode and/or anode.

20. The use of claim 17, 18 or claim 19, wherein the electrocatalyst is used to catalyse the production of oxygen at the anode.

21. A method for electrolyzing water comprising the steps of:

(ii) Contacting the water cell with water;

(iii) Creating an electrical bias between the cathode and the anode; and

(Iv) Hydrogen and/or oxygen is produced.

22. Use of a cathodic electrocatalyst comprising cobalt (Co) oxide, zirconium (Zr) and a noble metal for generating hydrogen via an electrolysis process.

23. A method for producing an electrode for an electrolytic cell, the electrode comprising a carrier and a coating, the method comprising the steps of:

preparing a metal support comprising nickel (Ni) or titanium (Ti),

Applying a coating comprising cobalt (Co), zirconium (Zr) and a noble metal on said support, and

Heating the support comprising the coating in air.

24. The method of claim 23, wherein the step of applying a coating comprising cobalt (Co), zirconium (Zr), and a noble metal on the support comprises:

The coating is applied by applying an aqueous-based solution comprising a metal salt precursor of cobalt (Co), zirconium (Zr) and a noble metal to the support.

25. The method of claim 23 or 24, wherein the method further comprises:

Preferably a viscosity modifier, preferably polyethylene glycol, is added prior to application of the coating.

26. The method of claim 23, 24 or 25, wherein the method further comprises:

The support and the coating are heated at a temperature between 300 ℃ and 600 ℃, preferably between 350 ℃ and 450 ℃.

27. The method according to one of claims 22-26, wherein the step of applying the coating on the carrier is preceded by the step of:

the carrier is etched with hydrochloric acid (HCL).