The present invention relates to the layered electrode for seawater electrolysis. Particularly, the invention relates to a double layer electrode for seawater electrolysis and process for preparation thereof, wherein the double layer electrode comprises a Molybdenum (Mo) based electrocatalyst layer. More particularly, the invention relates to a Molybdenum-sulphide (MoS) electrocatalyst layer uniformly coated over sulphonated Graphene (G) again deposited over porous Ni foam (Ni) as conducting substrate. The Ni-graphene substrate supported Molybdenum sulphide electrocatalyst electrode (Ni-G-MoS) possesses superior specificity for Hydrogen evolution reaction (HER) and Oxygen evolution reaction (OER) and repelling of Chlorine evolution reaction (CER) or chloride ions.
BACKGROUND OF THE INVENTION:
Electrochemical splitting of sea water is an effective strategy to produce renewable and sustainable hydrogen energy. Electrolysis of abundantly available seawater rather than scarce fresh water is a promising way to generate clean hydrogen energy. However, the biggest challenge in seawater splitting is the side chlorine evolution reaction at the anodic electrode together with leaching and rusting. The thought-provoking issues for seawater electrolysis comprises the competition of chlorine evolution reaction (CER) with oxygen evolution reaction (OER) on the anode, use of expensive electrocatalysts to sustain against chloride corrosion, and the formation of precipitates on the electrode surface.
In the last decade, various researchers have started working in this direction of sea water splitting. Many efforts have been made in the prior arts; some are as follows:
Vos and co-workers (J. Am. Chem. Soc. 2018, 140, 32, 10270-10281) proved that putting MnOx layer on the surface of Ir02 can effectively improve the efficiency of OER over CER. The MnOx layer acts as a sieve that disfavors the transport of

chloride ions. However, such materials are unable to generate high current density at low cell voltage, leading to a decrease in electrolyzer efficiency because the OER-inactive MnOx layer blocks the OER-active sites as well as developing additional resistance and the high cost of Ir limits its uses on an industrial scale.
Energy Environ. Sci., 2011, 4, 499-504, ChemSusChem, 2016, 9, 962-972, J. Mater. Chem. A, 2020, 8, 24501-24514, discloses an Ni-Fe layered double hydroxide (NiFe-LDH), Co phosphate, and Co-borate catalyst has been reported for high OER activity in alkaline KOH/NaCl electrolyte, but efficacy under real sea water was still limited and long-term durability at an industrial current density (CD.) of 1 A cm2 was not achieved.
Recently, Kuang et al. (Proceedings of the National Academy of Sciences of the United States of America- PNAS, 2019, 116, 6624-6629) developed Ni-Fe LDH electrode with in-situ generated polyatomic sulfate and carbonate-rich passivation layers. Such a negatively charged sulfate and carbonate layer repelled chloride ions and effectively improved the corrosion resistance of the salt-water-splitting typically at anodic center. This being the first and last report till date which well proved the implications of sulfonated and carbonated moieties in imparting corrosion resistance and chloride ions repellent.
Yu et al. (Energy Environ. Sci., 2020, 13, 3439-3446) also reported that by doping S in Ni/Fe hydroxide, stable seawater oxidation is possible. Splitting activity in saline water by S- based Ni- Fe catalysts appeared to be fine, but it is still associated with long term stability issue, stable catalysts has not been yet achieved for sea water splitting at industrial current density (CD.).
None of these prior art documents are still capable of utilizing pure sea water for hydrogen and oxygen generation. Typically, looking inside the concentration of pure sea water, the amount of salt type dissolved have 78, 11, 4, 3, 2 % of NaCl, MgCb, MgSC-4, CaSCM, K2S04 respectively, and the rest CaC03, and MgBr2. So,

in terms of competitive ions all these are present and influence the extent of electrode reactions (preferably HER and OER) and durability. If the catalyst would be target specific and have repelling properties against all these odd ions, then it might help in resolving the issue mentioned above under sea water spiting. Catalysts for sea water splitting involves high temperature processes for fabrications i.e. calcinating the same at 400-600 °C is an essential step, making it a tedious and energy consuming process, restricts their applicability for industrial scale and electrolyze construction.
Although the above prior arts provide electrocatalyst for sea water splitting, there still need of electrocatalyst electrode utilizing pure sea water for hydrogen and oxygen generation. Therefore, the present invention provides a layered electrode comprising Molybdenum-sulphide (MoS) electrocatalyst layer uniformly coated over sulphonated Graphene (G) again deposited over porous Ni foam (Ni) as conducting substrate for electrolysis of seawater having excellent durability quality. The electrodes fabricated altogether offered large surface area, high activity and durability which make it an ideal material for sea water splitting application. This superior electrochemical performance was attributed to the enhanced electron and ion transfer and synergistic effects of Mo-S and sulphonated graphene sheets. Hence, the design of anodes and electrolytes solves the chloride corrosion problem and allow direct splitting of seawater into renewable fuels without desalination. Catalyst of similar composition for sea water splitting has not been yet reported or tested. Specifically, there is no report which display the effect of sulphonated moieties in enhancing activity and repelling tendencies.
OBJECTS OF THE INVENTION:
The principal object of present invention is to provide a layered electrode for seawater electrolysis.

Another object of the invention is to provide a double layer electrode for seawater electrolysis comprising a Molybdenum (Mo) based electrocatalyst layer uniformly deposited on sulfonated Graphene again deposited over porous Ni foam (Ni) as conducting substrate.
Another object of the invention is to provide a novel electrode having superior catalytic activity and corrosion resistance properties in alkaline seawater electrolysis, allowing direct splitting of seawater into renewable fuels without desalination.
Another object of the invention is to provide a Ni-graphene substrate supported Molybdenum sulphide electrocatalyst electrode (Ni-G-MoS) that enhances Oxygen evolution reaction (OER) activity and Hydrogen evolution reaction (HER) activity and minimizes Chlorine evolution reaction (CER).
Another object of the invention is to provide development of a low-cost catalyst (Ni-G-MoS) owing to simple synthetic route of fabrication.
Yet another object of the invention is to provide a process for formation of a layer of Molybdenum sulphide (Mo-S) electrocatalyst over Graphene supported Nickel foam, with abundant sulphonic functionalized graphene which is altogether responsible for the high OER activity and corrosion resistance to chloride anions in seawater.
A further object of the invention is to provide a durable and robust electrocatalyst layer on electrode having high endurance power for surviving under harsh chlorous conditions.

SUMMARY OF THE INVENTION:
Accordingly, the present invention provides and discloses a layered electrode for seawater electrolysis. The present invention relates to a double layer electrocatalyst having a Molybdenum (Mo) based electrocatalyst layer. More particularly, the invention relates to a Molybdenum-sulphide (MoS) electrocatalyst layer uniformly coated over sulphonated Graphene (G) again deposited over porous Ni foam (Ni) as conducting substrate. The Ni-graphene substrate supported Molybdenum sulphide electrocatalyst possess superior specificity for Hydrogen evolution reaction (HER) and Oxygen evolution reaction (OER) and repelling of Chlorine evolution reaction (CER) or chloride ions.
The present invention provides low cost, robust, highly active electrode materials for large industrial scale sea water splitting. The low-cost catalyst material Ni-G-MoS synthesized via simple fabrication technique. Ni-G-MoS is highly durable, even it could survive under harsh condition in presence of sulphonated graphene, Mo-S chiefly. They altogether bring excessive active sites and high surface area for Hydrogen evolution reaction (HER) and Oxygen evolution reaction (OER) catalysis.
The most important is the sulphonated graphene generation inside Ni-G-MoS which imparted chlorine repellent tendency and making electrode specific for OER. Additionally, it added mechanical integrity into electrode and increases durability. The sulphonated graphene imparted chlorine repellent tendency into electrodes.
In one aspect, the present invention discloses a layered electrode for seawater electrolysis, characterized in that, the electrode comprises a Molybdenum (Mo) based electrocatalyst layer uniformly deposited on sulfonated Graphene (G) over a conducting substrate,
wherein the layers of the electrode comprise:

a first inner layer of sulphonated Graphene (G) coated over a conducting substrate of Nickel foam (Ni) forming a Nickel-Graphene (Ni-G) conductive substrate; and
a second outer layer of Molybdenum (Mo) based electrocatalyst uniformly deposited on Ni-G conductive substrate.
In the present invention the Molybdenum (Mo) based electrocatalyst layer is selected from Molybdenum-sulphides, Molybdenum-carbides, Molybdenum-phosphides, Molybdenum-borides, Molybdenum-nitrides, and alloys thereof.
The Molybdenum (Mo) based electrocatalyst layer of the present invention is Molybdenum-sulphides (MoS).
In another aspect, the present invention discloses a Nickel-Graphene-Molybdenum-sulphide (Ni-G-MoS) electrode for seawater electrolysis, comprises of layers coated over Ni-foam (Ni) conducting substrate, characterized in that the layers comprise:
- a first inner layer of Sulphonated Graphene (G) coated over a conducting
substrate of Nickel foam (Ni) forming a Nickel-Graphene (Ni-G) conductive substrate; and
- a second outer layer of Molybdenum-sulphide (MoS) electrocatalyst
uniformly deposited on Ni-G substrate,
wherein the sulphonated Graphene (G) deposited over Nickel foam (Ni) forms a protective layer at the time of generation of Molybdenum sulphide (MoS) electrocatalyst layer over the electrode and imparts high catalytic activity, superior specificity for HER and OER, repelling of CER reactions or chloride ions and enhanced durability in simulated sea water condition.
The said Ni-graphene (Ni-G) substrate supported Molybdenum sulphide (MoS) electrocatalyst electrode of the present invention possesses excellent activity and durability in alkaline seawater splitting.

In another aspect, the present invention discloses a simple synthetic route of fabrication of the Nickel-Graphene-Molybdenum-sulphide (Ni-G-MoS) electrode.
The fabrication of the Nickel-Graphene-Molybdenum-sulphide (Ni-G-MoS) electrode involves two steps:
a) a first step comprises preparing a Graphene oxide supported Ni foam electrodes
(Ni-G), and
b) a second step comprises in-situ generation of sulphonated Graphene Mo-S
nanoparticles deposited over Ni-G conductive substrate.
TheNickel-Graphene-Molybdenum-sulphide (Ni-G-MoS) electrode of the present invention has industrial faradaic current density (400-600 mAcm-2) < 1000 mV at combined over potential of Hydrogen evolution reaction (HER) and Oxygen evolution reaction (OER) and eliminates the side chloride oxidation reaction by being target specific and chlorine repelling.
The industrial current density of the said electrode is 700 mA/cm2 at the temperature of70°C.
In yet another aspect, the present invention discloses a novel process for preparation of Nickel-Graphene-Molybdenum-sulphide (Ni-G-MoS) electrode.
A process for preparation of Nickel-Graphene-Molybdenum-sulphide (Ni-G-MoS) electrode, wherein the process comprises steps of:
(a) coating and deposition of thick layer of Graphene (G) over Ni foam via dipping method or soaking method forming a Nickel-Graphene (Ni-G) conductive substrate; and
(b) in-situ generation of sulphonic groups and Mo-S nanoparticles catalyst over Ni-G conductive substrate,
wherein the in-situ immobilization of catalyst is proceeded via a hydrothermal process.

In the said process the hydrothermal process comprises:
adding the precursor's graphene deposited nickel and Mo-S into the hydrothermal bomb consisting of 10/60 ml of methanol/water, followed by keeping the hydrothermal bomb inside the muffle furnace operated at 180°C for 24 h.
The aim of the present invention is to develop a novel kind of electrode material Ni-G-MoS which would turn out to be extremely helpful in sea water electro-splitting process.
DETAILED DESCRIPTION OF THE INVENTION:
The present invention relates to a layered electrode for seawater electrolysis. The present invention provides a layered electrode comprising Molybdenum based electrocatalyst layer uniformly coated over sulphonated Graphene (G) again deposited over porous Ni foam (Ni) as conducting substrate for electrolysis of seawater splitting having excellent durability quality.
Generally, in seawater splitting, the side chlorine evolution reaction at the anodic electrode together with leaching and rusting is the main disadvantage. The thought-provoking issues for seawater electrolysis comprises the competition of chlorine evolution reaction (CER) with oxygen evolution reaction (OER) on the anode and use of expensive electrocatalysts to sustain against chloride corrosion, and the formation of precipitates on the electrode surface.
Typically, looking inside the concentration of pure sea water the amount of salt type dissolved have 78, 11, 4, 3, 2 % of NaCl, MgCb, MgS04, CaS04, K2S04 respectively, and the rest CaC03, and MgBr2. So, in terms of competitive ions all these are present and influence the extent of electrode reactions preferably Hydrogen evolution reaction (HER) and Oxygen evolution reaction (OER) and durability.

If the catalyst would be target specific and have repelling properties against all these odd ions, then it might help in resolving the issue mentioned above under sea water splitting. The present invention resolves all the problems by providing a double layer Molybdenum (Mo) based electrocatalyst electrode for seawater splitting.
The present invention discloses a layered electrode for seawater electrolysis wherein the electrode comprises a Molybdenum (Mo) based electrocatalyst layer uniformly deposited on sulfonated graphene over a conducting substrate. The layers of the electrode comprise:
a first inner layer of sulphonated Graphene (G) coated over a conducting substrate of Nickel foam (Ni) forming a Nickel-Graphene (Ni-G) conductive substrate; and
a second outer layer of Molybdenum (Mo) based electrocatalyst uniformly deposited on Ni-G conductive substrate.
The said layered electrode possesses excellent activity and durability in alkaline seawater splitting.
In the said electrode sea water electrolysis has been possible because of the formation of protective layer of abundant sulphonated graphene (G) over Ni-Foam (Ni). Also, it serves as supporting material for immobilization of Molybdenum (Mo) based electrocatalyst layer. It altogether increases the surface area and catalytic sites and provides good durability even in harsh condition. The electrode exhibits specificity for Oxygen evolution reaction (OER) process and has chlorine repelling tendencies.
In one embodiment of the invention the Molybdenum (Mo) based electrocatalyst layer is selected from Molybdenum-sulphides, Molybdenum-carbides,

Molybdenum-phosphides, Molybdenum-borides, Molybdenum-nitrides, and alloys thereof.
In one preferred embodiment of the invention the Molybdenum (Mo) based electrocatalyst layer is Molybdenum-sulphides (MoS).
According to said preferred embodiment, the present invention discloses a novel kind of electrode material Ni-G-MoS which is extremely helpful in sea water electro splitting process.
The present invention discloses a Nickel-Graphene-Molybdenum-sulphide (Ni-G-MoS) electrode for electrolysis of seawater consisting of layers coated over a conducting substrate of Ni-foam (Ni). The layers include:
- a first inner layer of Sulphonated Graphene (G) coated over a conducting
substrate of Nickel foam (Ni) forming a Nickel-Graphene (Ni-G) conductive substrate; and
- a second outer layer of Molybdenum-sulphide (MoS) electrocatalyst
uniformly deposited on Ni-G substrate,
wherein the sulphonated graphene deposited over Nickel foam (Ni) forms a protective layer at the time of generation of Molybdenum sulphide (MoS) electrocatalyst layer over the electrode and imparts high catalytic activity, superior specificity for HER and OER, repelling of CER reactions or chloride ions and enhanced durability in simulated sea water condition.
The said Ni-graphene substrate supported Molybdenum sulphide electrocatalyst electrode possesses excellent activity and durability in alkaline seawater splitting
The present invention discloses a double layer anode consisting of a Molybdenum sulfide electrocatalyst layer which is uniformly deposited on sulfonated graphene-Ni foam electrode, offering superior catalytic activity and corrosion resistance properties in alkaline seawater electrolysis. The specific design of the double layer

electrode is durable and exhibited an outstanding OER activity for seawater electrolysis. It requires very low over potential of 300 mV to reach current densities of 100 mAcm2 at 27 °C. This particular electrode can also withstand harsh condition of NaCl (0.5 M) for long duration.
Most importantly, the invention discloses that sulphonated form of graphene uniquely has safeguard properties, act like CI" repellent, enhances durability and minimized chlorine evolution reaction to good extent. Further, in situ-generated polyatomic sulfate over graphene oxide has been the responsible agent in maximizing activities and enhancing of the resistive factors.
Sea water electrolysis has been possible because of the formation of protective layer of abundant sulphonated graphene over Ni-Foam. Also, it serves as supporting material for immobilization of Mo-S. It altogether increases the surface area and catalytic sites. Good durability even in harsh condition (0.5/0.1 M ratio of NaCl/KOH) observed, activity under this border lining has not been reported. Industrial faradaic current density (400-600 mAcm-2) at combined over potential of HER and OER < 1000 mV has been achieved. Apart from this, the electrode exhibited specificity for OER process, and has chlorine repelling tendencies.
The resultant Ni-G-MoS electrode shows superior activity and corrosion resistance properties in alkaline seawater electrolysis. The superior chlorine repelling properties and target specificity inducted inside electrode accounts for high durability and activity. Moreover, the deposited graphene further added mechanical integrity to the electrodes.
The Ni-G-MoS electrode reach the desired industrial faradaic current density (400-600 mAcm-2 @ temperature between 40 -70 °C) below a 1000 mV combined over potential of Hydrogen evolution reaction (HER) and Oxygen evolution reaction (OER) and as well as eliminating the possibilities of chloride oxidation reaction by being target specific and chlorine repelling.

Ni-G-MoS stable active electrode for sea water splitting is the core product. Formation of sulphonated graphene protective layer over Ni-foam, brought additional benefits like chloride repellent tendency and added integrity into electrodes. It also serves as supportive material for uniform immobilization of nanoparticles Mo-S and combined together imparted high surface area and activity too.
Sulfur (S) is simultaneously introduced on the surface of Ni-Mo via doping with thiourea in-situ at the time of fabrication. These S induction inside Ni-Mo electrode component could tune the valence state of Ni/Mo, enhances the absorption energy of the OER intermediates and thus improving the OER activity. Importantly, graphene supported Ni enhances many of the properties of respective system catalyst. Both graphene and sulfur synergistically enhance stability with an improved water splitting performance. Also, functionalization with sulphonated moieties benefited with many desirable features like; superior specificity for HER and OER and repelling of CER reactions or chloride ions.
Two major problems which are solved by the present invention, are chiefly associated with sea water splitting and all credited to chloride ions.
- First is the competition between OER (oxygen evolution reaction) and CER
(Chlorine evolution reaction) owing to small potential difference of 0.48 V
between these two reactions (1-2). Selective OER than CER by electrode be
the most important challenge under this operation, somewhat it could be
overcome taking of alkaline electrolytes but still the kinetics show more
favorability to CER owing to 2e- transfer process.
2Cl-(aq) + OH- -> OC1- (aq) + H20 + 2e- E° = 0.89 V vs SHE, pH=14 (1)
40H-(aq) -> 02 (g) + 2H20 + 4e- E° = 0.41 V vs SHE, pH= 14 (2)
The minimization of CER is only possible by having electrode specific to OER and have chlorine repellent properties. The Ni-G-MoS electrode of the

present invention has the strong tendency to repel chlorine ions and is specific for OER process.
Second challenge is the long-term electrode durability as an industrial current density (400-1000 mA/cm2). The aggressive chloride anions have potential to corrode the active catalyst through metal chloride-hydroxide formation mechanisms. In the present invention, the Ni-G-MoS catalyst reach the desired industrial faradaic current density (400-600 mAcm"2 @ temperature between 40 -70 °C) below a 1000 mV combined over potential of HER and OER, and as well as enhancing the durability by being target specific and chlorine repelling. Moreover, it also lowers down the full over potential of HER and OER value which is the key requirement under this sea water splitting technologies.
With all prior knowledge, the present invention forward towards the fabrication step and have synthesized a target specific catalyst via simply one-step hydrothermal approach with prior mobilization of graphene over Ni- foam as support. Sulfur is simultaneously introduced on the surface and in the lattice of Molybdenum catalyst during the reaction.
Importantly, graphene supported over Ni introduces two essentials features inside catalyst system, first is the integrity and second the specificity for electrode process typically Oxygen evolution reaction (OER).
It is mainly owing to the functionalization of sulphonated moieties over graphene. In situ-generated polyatomic sulfate over graphene oxide has been the responsible agent in maximizing activities and enhancing of the resistive factors.
The present invention discloses the sulphonated graphene generation inside Ni-G-MoS which imparts chlorine repellent tendency and making electrode specific for

Oxygen evolution reaction (OER). Additionally, it added mechanical integrity into electrode and increases durability.
Ni-G-MoS electrode has superior activity, industrial current density of 700 mA/cm2 at the temperature of 70 °C has been achieved.
The foremost characteristic is that Ni-G-MoS is highly durable, even it could survive under harsh condition. It all credited to presence of sulphonated graphene, Mo-S chiefly. They altogether bring excessive active sites and high surface area for HER and OER catalysis. Typically, sulphonated graphene imparted chlorine repellent tendency into electrodes.
Present invention discloses a Ni-graphene substrate supported Molybdenum sulphide electrocatalyst electrode (Ni-G-MoS).
The role of important components are discussed below:
(i) Graphene- Graphene brings many benefits like it enhances the conductivity of electrocatalyst, it also accelerates the charge transfer kinetics of overall system. It improves the uniform dispersion of loaded catalyst or electro active components, thus providing more catalytic active sites, suppresses catalytic leaching and aggregation under harsh conditions, thus elongating the life-time of electrocatalyst and stability in broad pH conditions, modulate the electronic structure of active center as a result of synergistic interaction between graphene and electro active components (TMCs), thus improving their catalytic activity. Most importantly, its low cost, make them available for large scale commercialization purpose.
(ii) Ni foam- Commercial porous conductive substrates and it would provide an underlying network for the fabrication of three-dimensional (3D) architectures electrodes, offering large interfacial areas, reduced ionic diffusion distances and facilitate charge separation and transport. The unique properties of conductive foams, such as high specific surface area and structural rigidity, make them suitable

and popular freestanding support on which the active catalyst materials can be grown.
(iii) Molybdenum Sulfide (Mo-S) - Mo-S found to be an efficient electrocatalyst. Among all the transition metal sulfide (TMS), the molybdenum sulphides catalyst has attracted immense attention owing to their impressive catalytic activity and hydrogenase properties. But to further enhance the activity several alterations like, functionalization, doping with Co-element, etc., would be proceeded. Generally, a facile solvothermal approach is well enough to synthesize the Mo-S nanoparticles.
Fabrication of electrode:
Further, the invention discloses a low cost, robust, highly active electrode materials for large industrial scale sea water splitting. The invention provides a low-cost catalyst material Ni-G-MoS synthesized via simple fabrication technique.
The fabrication of the said electrode involves two steps:
a) a first step comprises preparing a Graphene oxide supported Ni foam electrodes
(Ni-G), and
b) a second step comprises in-situ generation of sulphonated Graphene Mo-S
nanoparticles deposited over Ni-G conductive substrate.
PROCESS FOR PREPARATION:
The present invention provides a process for preparation of Ni-G-MoS electrode. The invention provides a method/step for preparing a double layer anode consisting of a Molybdenum sulfide electrocatalyst layer, uniformly deposited on sulfonated graphene Ni-foam electrode offering superior catalytic activity and corrosion resistance properties in alkaline seawater electrolysis.

Accordingly, present invention discloses a process for preparation of Nickel-Graphene-Molybdenum-sulphide (Ni-G-MoS) electrode, wherein the process comprises steps of:
(a) coating and deposition of thick layer of Graphene (G) over Ni foam via dipping method or soaking method forming a Nickel-Graphene (Ni-G) conductive substrate; and
(b) in-situ generation of sulphonic groups and Mo-S nanoparticles catalyst over Ni-G conductive substrate,
wherein the in-situ immobilization of catalyst is proceeded via a hydrothermal process.
The present invention discloses two step procedure, which are explained below in details:
(a) Preparing Graphene oxide Supported Ni foam electrodes (Ni-G)
In this step the Ni-foam is coated and deposited by the thick layer of the graphene. The coating and deposition of thick layer of graphene over Ni foam can be done via simple and effective dipping method or soaking method. Dipping or soaking method of electrodes provides more uniformly distribution of the graphene layer.
(b) In-situ Sulphonated Graphene alongside Mo-S deposition over Ni-G
In the second step, the product of first step i.e. Nickel Graphene (Ni-G) is coated and deposited via the hydrothermal deposition of active components (nanoparticles catalyst over to conductive substrate). The molybdenum sulphide electrocatalyst layer has been uniformly coated over graphene oxide Supported Ni foam electrodes (Ni-G). Thus, after completing both the steps resulted electrode forms Ni-G-MoS. The deposition of graphene over Ni-foam, the formation of abundant sulphonated graphene or sulphonic groups over graphene is highly advantageous. Further, the

presence of sulphonic group is critically essential in catalyst as defending component against chloride ions.
During this optimization the in-situ formation of sulphonated graphene with Mo-S deposition, over Ni substrate appeared to be very effective. Their formation is highly remarkable, it introduces many valuable properties to Ni-G-MoS and altogether make them viable for sea water splitting application. Significant improvement in activity and stability observed owing to the presence of sulphonated form of graphene inside Ni-G-MoS.
Role of sulphonated graphene is in enhancing of durability, integrity and more importantly imparting of chloride repelling tendency inside the catalyst system.
The major components Ni foam (Ni) deposited Graphene and Mo-S come in contact at the time of fabrication process via hydrothermal approach. There is a uniform growth of nanoparticles of Mo-S all over the substrate. This has been confirmed by the Scanning Electron Microscopy (SEM) micrograph taken for respective catalyst. It confirms the interaction between Mo-S and graphene. It also results into appearance of sulphonated functional groups on graphene.
Overall, the novel aspects are the formation of a layer of Mo-S catalyst over graphene supported Nickel-foam, with abundant sulphonic functionalized graphene which is altogether responsible for the high OER activity and corrosion resistance to chloride anions in seawater. The Ni-G-MoS exhibited higher OER activity than the bare Ni-MoS or Ni-G and it is owing to synergistic cooperation of all the components Ni foam, sulphonated graphene, Mo-S.
The process consists of two steps- the first is the deposition of graphene oxide over Nickel foam (Ni-G). The second step involves the in-situ generation of sulphonic groups and Mo-S nanoparticles over Ni-G conductive substrate. The in-situ immobilization of catalyst has proceeded via a facile hydrothermal process. This

quick fabrication cuts down the use of sophisticated instrument and high temperature which one generally used in making of active catalysts.
Simple hydrothermal approach was used in fabrication of electrode. The precursor's graphene deposited nickel and Mo-S were added into the hydrothermal bomb consisted of 10/60 ml of methanol/water. After the addition, the hydrothermal bomb was kept inside the muffle furnace for in-situ immobilization of nanocatalyst. Electrode fabrication process is highly feasible with as ease in operation. The essentials here under this optimization is the use of hydrothermal bomb and temperature of 180 °C, without which immobilization of catalyst is difficult. For said immobilization, the muffle furnace was operated at 180 °C for 24 h.
Present invention provides completely new approach of electrode fabrication and very simple in operation.
Sulphonic group abundantly appeared on the surface of catalyst by in-situ fabrication Ni-G-MoS and has been the responsible agent in bringing in excellent durability inside system, even in harsh conditions. Furthermore, in terms of applicability of developed product Ni-G-MoS, this particular has used as electrode materials for sea water splitting in commercially acceptable range. The Ni-G-MoS is highly active and durable. Electrode catalyst Ni-G-MoS reach the desired industrial faradaic current density of 400-600 mAcm"2 @ temperature between 40 -70 °C at combined over potential of ITER and OER < 1000 mV, and as well as possesses good durability.
The fabricated Ni-G-MoS catalyst product is highly unique, formation of sulphonated graphene as protective layer in Ni-G-MoS is highly appreciable for sea water splitting. This Ni-G-MoS could be achieved by simple fabrication process. This quick fabrication cuts down the use of sophisticated instrument. Persistence of durability at industrial current density (400-1000 mA/cm2) make them available for large scale production.

Ni-G-MoS electrodes would be used as electrode material in electrolyzer for large scale production of H2 and O2. Most importantly, it allows the direct use of abundant sea water as electrolyte. It possesses great durability in harsh sea water conditions and this quality is essential requirement in establishing technology of sea water splitting. The Ni-G-MoS electrodes could be used in companies especially working towards commercialization of electrolyzers and production of H2, i.e. for example various oil & gas domain public sector and private sector companies.
Sea water electrolysis has been possible because of the formation of protective layer of abundant sulphonated graphene over Ni-Foam. Also, it serves as supporting material for immobilization of Mo-S. It altogether increases the surface area and catalytic sites. Good durability even in harsh condition (0.5/0.1 M ratio of NaCl/KOH) observed, activity under this border lining has not been reported. Industrial faradaic current density (400-600 mAcm"2) at combined over potential of HER and OER < 1000 mV has been achieved. Apart from this, the electrode exhibited specificity for OER process, and has chlorine repelling tendencies.
The inventors of the present invention have verified that bare electrodes (in absence of sulphonated graphene) wouldn't even withstand the harsh condition even for half an hour. The electrodes fabricated altogether of the present invention offered large surface area, high activity and durability which makes it an ideal material for sea water splitting application. This superior electrochemical performance was attributed to the enhanced electron and ion transfer and synergistic effects of Mo-S and sulphonated graphene sheets. Hence, careful design of anodes and electrolytes can fully solve the chloride corrosion problem and allow direct splitting of seawater into renewable fuels without desalination, it has been well supported by the below example.

Activity optimization and study of chloride repellent tendency
The performances of the catalyst material were measured in an alkaline seawater electrolyte by varying concentration ratios of KOH:NaCl in three-electrode cell configuration.
The electrochemical performance of electrodes was evaluated using u-Autolab III potentiostat involving three electrode configurations with:
platinum metal as counter electrode,
Ag/AgCl as reference electrode, and - Ni-G-MoS as working electrode.
All these three electrodes were dipped in 2/0.5 M ratio of KOH/NaCl (simulated alkaline seawater), the same were also tested in 0.1/0.5 M ratio of KOH/NaCl, at particular as harsh condition. The catalyst was first stabilized by cyclic voltammetry (CV) at a 30 mV s"1 scan rate in the potential window of-1.5 to 0.7 V vs. Ag/AgCl, then the LSV experiments were conducted at a scan rate 5 mV s"1. Chronoamperometry studies were carried out to check the stability and the durability of the working electrode with time. Studies on varying temperature and potential were done with DC voltage source in two electrode configurations. The purpose was to understand the phenomena associated with the electrode process under simulated alkaline sea water condition.
Acceptable industrial current density 400-1000 mA/cm2 by Ni-G-Mo-S in simulated alkaline (2M KOH) sea water, has been achieved at the temperature between 40-70 °C only by the Ni-G-MoS working electrode. Thus, in the present electrode for sea water splitting the temperature is vital criteria, below 40 °C the industrial current density (CD) would be difficult to achieve. Industrial current density at room temperature would also be possible by increasing alkalinity.

Optimum Condition:
(a) Optimum condition for the fabrication of electrode product- Ni-G-MoS
Simple hydrothermal approach has been used in fabrication of electrode. The precursor's graphene deposited nickel and Mo-S were added into the hydrothermal bomb consisted of 10/60 ml of methanol/water. After the addition, the hydrothermal bomb was kept inside the muffle furnace operated at 180 °C for 24 h.
Electrode fabrication process is highly feasible with as ease in operation. The essentials here under this optimization is the use of hydrothermal bomb and temperature of 180°C, without which immobilization of catalyst is difficult.
(b) Optimum condition to achieve industrial current density by Ni-G-MoS
Acceptable industrial current density 400-1000 mA/cm2 by Ni-G-Mo-S in simulated alkaline (2M KOH) sea water, has been achieved at the temperature between 40-70°C only. Accordingly, the present electrode for sea water splitting the temperature is vital criteria, below 40°C the industrial CD would be difficult to achieve. Industrial current density at room temperature would also be possible by increasing alkalinity.
The best ideal condition to achieve industrial current density 700 mA cm"2 by bi-functional Ni-G-MOS at combined over potential < 1000 mV of HER and OER has been 0.5/2 M ratio of NaCl/KOH, and at the temperature of 70 °C.
ADVANTAGES OF THE INVENTION:
The present invention provides a layered electrode for seawater electrolysis. The implemented steps are very unique and novel kind of electrode material Ni-G-MoS has been developed which would turn out to be extremely helpful in sea water

electro splitting process. Most importantly, the present invention has suggested that sulphonated form of graphene uniquely have safeguard properties, act like CI" repellent, enhances durability and minimized chlorine evolution reaction to good extent.
The major advantages associated with the present fabricated electrode Ni-G-MoS are the following:
(a) The foremost is the development of a low-cost catalyst (Ni-G-MoS) owing to
simple synthetic route of fabrication.
(b) Second is the high activity, which is because of the Mo-S nano catalyst uniformly deposition over graphene oxide Ni conductive substrate, which altogether extends its surface area, hence increases the activity.
(c) Third is the in-situ conversion of graphene oxide to sulphonated form of graphene which inducted chloride resistance properties and making them selective for OER and HER. All other side reactions get terminated. Also, it imparted excellent durability and integrity within catalyst system.
Overall, the electrodes of the present invention offered large surface area, high activity and durability which make it an ideal electrode material for sea water splitting.

We claim:

1. A layered electrode for seawater electrolysis, characterized in that, the electrode
comprises a Molybdenum (Mo) based electrocatalyst layer uniformly deposited
on sulfonated Graphene (G) over a conducting substrate,
wherein the layers of the electrode comprise:
a first inner layer of sulphonated Graphene (G) coated over a conducting substrate of Nickel foam (Ni) forming a Nickel-Graphene (Ni-G) conductive substrate; and
a second outer layer of Molybdenum (Mo) based electrocatalyst uniformly deposited on Ni-G conductive substrate.
2. The layered electrode as claimed in claim 1, wherein the Molybdenum (Mo) based electrocatalyst layer is selected from Molybdenum-sulphides, Molybdenum-carbides, Molybdenum-phosphides, Molybdenum-borides, Molybdenum-nitrides, and alloys thereof.
3. The layered electrode as claimed in claim 1, wherein the Molybdenum (Mo) based electrocatalyst layer is Molybdenum-sulphides (MoS).
4. A Nickel-Graphene-Molybdenum-sulphide (Ni-G-MoS) electrode for seawater electrolysis comprises of layers coated overNi-foam (Ni) conducting substrate, characterized in that the layers comprise:
- a first inner layer of Sulphonated Graphene (G) coated over a conducting
substrate of Nickel foam (Ni) forming a Nickel-Graphene (Ni-G) conductive substrate; and
- a second outer layer of Molybdenum-sulphide (MoS) electrocatalyst
uniformly deposited on Ni-G substrate,
wherein the sulphonated Graphene (G) deposited over Nickel foam (Ni) forms a protective layer at the time of generation of Molybdenum sulphide (MoS) electrocatalyst layer over the electrode and imparts high catalytic activity,

superior specificity for HER and OER, repelling of CER reactions or chloride ions and enhanced durability in simulated sea water condition.
5. The electrode as claimed in claim 4, wherein the said Ni-graphene (Ni-G) substrate supported Molybdenum sulphide (MoS) electrocatalyst electrode possesses excellent activity and durability in alkaline seawater splitting.
6. The electrode as claimed in claim 4, wherein the fabrication of the said electrode involves two steps:
a) a first step comprises preparing a Graphene oxide supported Ni foam
electrodes (Ni-G), and
b) a second step comprises in-situ generation of sulphonated Graphene Mo-S
nanoparticles deposited over Ni-G conductive substrate.
7. The electrode as claimed in claim 4, wherein the said electrode has industrial
faradaic current density (400-600 mAcm-2) < 1000 mV at combined over
potential of Hydrogen evolution reaction (HER) and Oxygen evolution reaction
(OER) and eliminates the side chloride oxidation reaction by being target
specific and chlorine repelling.
8. The electrode as claimed in claim 4, wherein the industrial current density of the said electrode is 700 mA/cm2 at the temperature of 70 °C.
9. A process for preparation of Nickel-Graphene-Molybdenum-sulphide (Ni-G-MoS) electrode, wherein the process comprises steps of:

(a) coating and deposition of thick layer of Graphene (G) over Ni foam via dipping method or soaking method forming a Nickel-Graphene (Ni-G) conductive substrate; and
(b) in-situ generation of sulphonic groups and Mo-S nanoparticles catalyst over Ni-G conductive substrate,

wherein the in-situ immobilization of catalyst is proceeded via a hydrothermal process.
10. The process as claimed in claim 9, wherein the hydrothermal process comprises: adding the precursor's graphene deposited nickel and Mo-S into the hydrothermal bomb consisting of 10/60 ml of methanol/water, followed by keeping the hydrothermal bomb inside the muffle furnace operated at 180°C for 24 h.