ELECTROCATALYTIC REDUCTION OF GREEN-HOUSE GAS (GHG) EMISSIONS INTO p-XYLENE AND OTHER VALUE-ADDED PRODUCTS

Abstract

An electrocatalytic reactor for conversion of Green House Gas (GHG) emissions that include CO2, CH4 and N2 into p-Xylene and other value-added products (VAPs), wherein the electrocatalytic reactor is equipped with symmetric or asymmetric electrodes (cathode and anode) that act as electrocatalyst, which are dipped in an electrolytic reaction solution that includes acidified deionised water (H3O+) and a catalyst initiator An external current of 1 to 5 A applied to the electrodes in a voltage range of 1 to 5 V, which initiates C-C coupling or C-O coupling reactions on the cathode surface forming short-lived cation radical intermediates, wherein the short-lived cation radical intermediates react among themselves, or react with in-situ produced H2 gas, leading to the formation of p-Xylene as the major product and other VAPs, wherein the other VAPs formed include benzene, toluene and substituted benzene.

Description

[0001] TITLE

[0002] ELECTROCATALYTIC REDUCTION OF GREEN-HOUSE GAS (GHG) EMISSIONS INTO -X YLENE AND OTHER VALUE-ADDED PRODUCTS

[0003] CROSS REFERENCE TO RELATED APPLICATIONS

[0004] The present application is based upon and claims priority to India complete patent application number 202443036111 filed on May 07, 2024, which is an improvement or modification to the invention disclosed in PCT / IN2024 / 050242 filed on March 09, 2024 and the corresponding India complete patent application number 202341066700 filed on March 08, 2024, which in turn is based upon and claims priority to India provisional patent application number 202341066700 filed on October 05, 2023, the entire contents of which are herein incorporated by reference.

[0005] FIELD

[0006] The present disclosure relates to conversion of green-house gas (GHG) emissions into -Xylcnc and other value-added products (VAPs), more particularly relates to electrocatalytic C-C coupling and C-0 coupling reduction of green-house gas (GHG) emissions into -Xylcnc as the major product.

[0007] BACKGROUND

[0008] Gases that trap heat in the atmosphere are called greenhouse gases (GHG). During the daytime, the sun warms the earth’s surface by shining through the atmosphere, and at night, the earth's surface cools, releasing the heat back into the air. But some of the heat is trapped by the greenhouse gases in the atmosphere. That's what keeps the earth’s temperature at an average 14°C (57°F). The gases act like the glass walls of a greenhouse - hence the name, greenhouse gases. Without this greenhouse effect, temperatures would drop to as low as -18°C (-0.4°F); too cold to sustain life on earth. But human activities are changing earth's natural greenhouse effect with a dramatic increase in the release of greenhouse gases. Scientists agree greenhouse gases are the cause of global warming and climate change. Since the Industrial Revolution, humans have been releasing larger quantities of greenhouse gases into the atmosphere. In the past century that amount has increased dramatically, with the knock-on effect of global warming. Global temperatures have accelerated in the past 30 years and are now the highest since records began. Greenhouse gases include carbon dioxide, methane, ozone, nitrous oxide, chlorofluorocarbons, and water vapor.

[0009] The urgency of the climate crisis and the increase in natural gas production accelerate the need for an efficient way to convert GHG such as methane into liquid fuels and other commodity chemicals. p-Xylene is the prime and vital constituent in the paint, varnish, chemical industry. Conventionally, p-Xylene is used as organic solvent in many organic reactions in pharmaceuticals as well. Normally, the source of methane is feedstock from natural gas, coal bed, methane hydrate due to its less cost and abundance. As the methane conversion to p-Xylene is a high temperature operated process i.e., 700-850°C, a direct conversion of methane without forming syngas as intermediate makes the process more economical and environmentally benign. Therefore, design and development of process and technology for selective conversion of methane to high-value-added chemicals under room temperature and ambient conditions becomes a challenging task. It had been demonstrated at R&D scale that metal complexes of Hg, Pt, Pd, Au, Ru, Rh, and V acts as catalyst for selective oxidation of methane in a strong acid medium, such as oleum, trifluoroacetic acid, hydrochloric acid, or hydrobromic acid at 80°C-500°C. Other methods involved molecule-sieve-based catalysts, such as ZSM-518-21 and MOR, to convert methane to methanol at much lower temperatures like 50°C- 225°C. But all the said methods or catalysts converted methane with low yield. Thus, the major bottleneck involves (i) the direct room-temperature conversion of methane without other energy input and (ii) replacement of precious-metal catalysts.

[0010] Hence, there is a need for developing an electrocatalytic technology that can directly convert methane into p-Xylene with high selectivity and specificity with optimum Faradaic Efficiency (FE%) of methane and GHG conversion with specificity to p-Xylene as the major product. IN202341047481 discloses a method of electrochemical conversion of carbon dioxide into value-added products, wherein the method utilises an electrochemical reactor having metallic Copper (Cu) or Cu-alloy symmetric electrodes (cathode and anode).

[0011] US9816035B2 discloses a process and system for producing a synthetic hydrocarbon having a desired H / C ratio is disclosed. Organic material is biochemically digested in a two stage biodigester for separately producing a hydrogen containing biogas substantially free of methane in a first stage and a methane containing biogas in a second stage. The methane containing biogas is reformed in a first reformer to generate hydrogen gas and carbon monoxide gas, which are then combined in a mixer with the hydrogen containing biogas into a syngas in amounts to achieve in the syngas an overall H / C ratio substantially equal to the desired H / C ratio. The syngas is reacted with a catalyst in a second reformer, a Fischer-Tropsch (FT) reactor, to produce the hydrocarbon. Using a two stage biodigester allows for the generation of separate hydrogen and methane streams, a more economical generation of the FT syngas and reduced fouling of the FT catalyst.

[0012] US9163180B2 discloses a process for the conversion of carbon-based material to fuel bases by a hybrid route combining direct ebullent bed liquefaction and indirect liquefaction by gasification followed by a Fischer-Tropsch synthesis, including a stage of production of hydrogen resulting from non-fossil resources and a reverse water gas reaction stage

[0013] US20230287286A1 discloses processes for producing high biogenic concentration Fischer-Tropsch liquids derived from the organic fraction of municipal solid wastes (MSW) feedstock that contains a relatively high concentration of biogenic carbon (derived from plants) and a relatively low concentration of non-biogenic carbon (derived from fossil sources) wherein the biogenic content of the Fischer-Tropsch liquids is the same as the biogenic content of the feedstock. WO2020176575A1 discloses method of electrochemical reduction of CO2 includes the use of a catalyst of CU / CU2O particles including CU / CU2O interfaces, which is included in an electrochemical cell for the conversion of CO2 to value- added products. The electrochemical cell may include an anode, a cathode including the CU / CU2O particles including CU / CU2O interfaces, and an aqueous medium containing CO2 or CO3’2. The CO2 or CO3’2is reduced by contacting the CU / CU2O particles with the aqueous medium while supplying electricity to the cell.

[0014] Journal article, “Oxide Derived Copper for Electrochemical Reduction of CO2 to C2+Products”, Nanomaterials, 2022, 12(8):1380; doi:10.3390 / nanol2081380, discloses a study directed to electrochemical reduction of CO2 on copper electrode derived from cupric oxide (CuO), named oxide derived copper (ODCu), in the potential range of -1.0 V to -1.5 V versus RHE. The CuO nanoparticles were prepared by the hydrothermal method. The ODCu electrode was used for carbon dioxide reduction and the results revealed that this electrode is highly selective for C2+products with enhanced current density at significantly less overpotential.

[0015] Journal article “Electroreduction of carbon dioxide to hydrocarbons using bimetallic Cu-Pd catalysts with different mixing patterns”, J. Am. Chem. Soc. 2017, vol. 139, issue.l, pages: 47-50; doi:10.1021 / jacs.6bl0740, discloses bimetallic Cu-Pd catalysts for reduction of carbon dioxide to Ci or C2 chemicals.

[0016] CN 104321293 A discloses a process for the preparation of methanol having the process a carbon oxides per-pass conversion equal to or higher than 65%, and a selectivity to methanol formation equal to or higher than 75% by submitting carbon dioxide, carbon monoxide or a mixture of carbon monoxide and carbon dioxide to a hydrogenation reaction using a specific metal compound and specific reaction conditions of temperature, pressure, space velocity and a specific range of molar ratio of hydrogen to carbon dioxide, of hydrogen to carbon monoxide, or of hydrogen to the mixture of carbon monoxide and carbon dioxide. It further relates to a process for converting the methanol obtained into dimethyl ether or into a mixture of (C2-C8) alkene and (C1-C8) alkane.

[0017] Journal article “Chong Wang et al. Silver-modified copper foam electrodes for enhanced reduction of CO2 to C2+ products, Mater. Adv., 2022, 3, 4964-4972, DOI: 10.1039 / D2MA00188H” discloses an Ag-modified Cu / CuO-Ag catalyst with a porous structure via a galvanic replacement reaction method, which reduced CO2 to C2+ products with the faradic efficiency (FE) of 52.5% at 1.1 V (vs. RHE). DI states that the experimental results and density functional theory (DFT) calculations show that the addition of Ag in Cu is beneficial to increasing the coverage of *CO on the Cu surface, which can decrease the potential barrier energy of the C-C coupling reaction and favour the generation of C2+ products.

[0018] Journal article “Mun, Yeongdong et al. (2019). Cu-Pd Alloy Nanoparticles as Highly Selective Catalysts for Efficient Electrochemical Reduction of CO2 to CO. Applied Catalysis B: Environmental, (), S0926337319300219. doi: 10.1016 / j.apcatb.2019.01.021” discloses alloying of Cu with Cu-Pd in 1:1 ratio achieves CO2 to CO electrochemical reduction of 87% CO faradic efficiency (FE). D2 discloses that this increase in the FE of CO2 to CO conversion suppresses the formation of hydrocarbons from CO2.

[0019] Journal article “M. Watanabe, M. Shibata, A. Kato, M. Azuma, T. Sakata, J. Electrochem. Soc. 1991, 138, 3382-3389” discloses Cu based alloys such as Cu- Zn, Cu-Cd, Cu-Ag, Cu-Sn and Cu-Pb as electrocatalyst for CO2 electrochemical reduction into CH3OH, HCOOH, and CO in highly selective approach via low overpotentials on Cu-alloy catalysts.

[0020] US2022119966A1 discloses a method of electrochemical reduction of CO2 involving the use of a catalyst of Cu / Cu2O nanoparticles including Cu / Cu2O interfaces wherein the catalyst may be included in an electrochemical cell for the conversion of CO2 to value-added products. The electrochemical cell may include an anode, a cathode including the Cu / CmO nanoparticles including Cu / Cu2O interfaces. GB202202262D0 discloses a catalyst for the electrochemical conversion of carbon dioxide or carbon monoxide to a C2+ product wherein the catalyst comprises copper and a metal (M) selected from the group consisting of: yttrium (Y), zinc (Zn), lanthanum (La) and gadolinium (Gd); wherein the molar ratio of Cu: M is from 100: 1 to 100: 10.

[0021] SUMMARY

[0022] The present disclosure provides an electrocatalytic reactor for conversion of Green House Gas (GHG) emissions that include CO2, CH4 and N2 into -Xylcnc and other value-added products (VAPs), wherein the electrocatalytic reactor is equipped with electrodes (cathode and anode), wherein the cathode includes a combination of a Steel electrode and one or more of a metallic Copper (Cu), a Cu- alloy, or a Cu-doped Ti mesh electrode, and the anode is selected from metallic Copper (Cu), Cu alloy, Ti Mesh, Cu-doped Ti Mesh, wherein these electrodes act as electrocatalyst, and acidified deionised water (H3O+) as electrolyte for generation of H2 gas through bulk electrocatalysis, wherein a catalyst initiator is included in the acidified deionised water (H3O+).

[0023] The method of electrocatalytic reduction operation occurs at ambient temperature, and 1 atm pressure. An external current of 1 to 5 A was applied to the electrodes in a voltage range of 1 to 5 V, which initiates C-C coupling or C-0 coupling reactions on the cathode surface forming short-lived cation radical intermediates, wherein the short-lived cation radical intermediates react among themselves, or the short-lived cation radical intermediates react with the in-situ produced H2 gas, or both, leading to the formation of -Xylcnc as the major product and other VAPs, wherein the other VAPs formed include benzene, toluene and substituted benzene.

[0024] The concentrated acid is selected from HC1, H2SO4, HNO3, H3PO4.

[0025] The catalyst initiator is a mixture of 60% by weight of carbonates or bicarbonates of Mg or Na or K or a combination of carbonates and bicarbonates of Mg, Na and K with 40% by weight of MgO. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0026] Fig. 1 illustrates the design of the electrocatalytic reactor to convert GHG to p- Xylene as the major product, and other value-added products (VAPs).

[0027] Fig. 2 illustrates GC-MS spectra of the product solution obtained by the electrocatalytic reduction of GHG in Example 1.

[0028] Fig. 3 illustrates GC-MS spectra of the product solution obtained by the electrocatalytic reduction of GHG in Example 2.

[0029] Fig. 4 illustrates GC-MS spectra of the product solution obtained by the electrocatalytic reduction of GHG in Example 3.

[0030] Fig. 5 illustrates the reaction mechanism of the VAPs formed from the reduction of GHG.

[0031] DETAILED DESCRIPTION

[0032] The subject matter of the present disclosure is described in detail with reference to the accompanying drawings. Unless otherwise specified, all the technical and scientific terms used herein have the same meaning as is generally understood by a person skilled in the art pertaining to the present disclosure. Headings are used solely for organizational purposes, and are not intended to limit the disclosure in any way.

[0033] The use of the singular includes the plural unless specifically stated otherwise. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well. The use of “or” means “and / or” unless stated otherwise. Unless otherwise indicated, all numbers used herein to express quantities, dimensions, and so forth used should be understood as being modified in all instances by the term "about." It is to be understood that wherein a numerical range is recited, it includes all values within that range, and all narrower ranges within that range, whether specifically recited or not. As used herein, "including," "containing" and like terms are understood to be synonymous with "comprising" and are therefore open-ended and do not exclude the presence of additional undescribed or unrecited elements, materials, phases or method steps.

[0034] In addition, it should be appreciated that any figures are provided herewith, they are for explanation purposes to persons ordinarily skilled in the art and that the drawings of them are not necessarily drawn to scale.

[0035] Any method / process steps and / or operations and / or instructions used in this disclosure, are for illustrative purposes in a particular order and / or grouping. Other orders and / or grouping of the process steps or its portions and / or operations or its portions and / or instructions or its portions are possible and, one or more of the process steps and / or operations and / or instructions can be combined and / or deleted.

[0036] The present disclosure provides an electrocatalytic reactor and method for electrocatalytic reduction of Green House Gase (GHG) emissions that include CO2, CH4 and N2 into -Xylcnc and other value-added products (VAPs), wherein the other VAPs formed include benzene, toluene and substituted benzene.

[0037] The method of electrocatalytic reduction operation occurs at ambient temperature, and 1 atm pressure. An external current of 1 to 5 A was applied to the electrodes in a voltage range of 1 to 5 V, which initiates C-C coupling or C-0 coupling reactions on the cathode surface forming short-lived cation radical intermediates, wherein the short-lived cation radical intermediates react among themselves, or the short-lived cation radical intermediates react with the in-situ produced H2 gas, or both, leading to the formation of -Xylcnc as the major product and other VAPs, wherein the other VAPs formed include benzene, toluene and substituted benzene.

[0038] In an aspect CH4 in the GHG is electrocatalytically reduced to ethylene through the following reaction pathway:

[0039] 2CH4->C2H6+ 4H++ 2e"

[0040] The pathway of the elementary steps involves The electrocatalytic reactor:

[0041] The electrocatalytic reactor of the present disclosure for conversion of Green House Gas (GHG) emissions that include CO2, CH4 and N2 into -Xylcnc and other value-added products (VAPs), wherein the electrocatalytic reactor is equipped with electrodes (cathode and anode), wherein the cathode includes a combination of a Steel electrode and one or more of a metallic Copper (Cu), a Cu- alloy, or a Cu-doped Ti mesh electrode, and the anode is selected from metallic Copper (Cu), Cu alloy, Ti Mesh, Cu-doped Ti Mesh, wherein these electrodes act as electrocatalyst, and acidified deionised water (H3O+) as electrolyte for generation of H2 gas through bulk electrocatalysis, wherein a catalyst initiator is included in the acidified deionised water (H3O+).

[0042] In an aspect, the steel electrode is Stainless Steel.

[0043] In an aspect, the reactor vessel is made of Stainless Steel (SS), wherein the reactor vessel is enabled to act as the steel cathode by applying current density to the reactor vessel.

[0044] In another aspect, the steel electrode is mild Steel, where the mild steel electrode gets consumed in the electrocatalytic reaction process.

[0045] In an aspect, the reactor vessel is a double-walled reactor vessel, wherein the inner wall that comes in direct contact with the reaction solution is made of mild steel, and the outer wall is made of Stainless Steel (SS), wherein the inner mild steel wall of the reactor vessel is enabled to act as the steel cathode by applying current density to the reactor vessel.

[0046] A representation of the electrocatalytic reactor is shown in Fig. 1.

[0047] The catalyst initiator:

[0048] The catalyst initiator for the present disclosure is a mixture of 60% by weight of carbonates or bicarbonates of Mg or Na or a combination of carbonates and bicarbonates of Mg and Na with 40% by weight of MgO, which in distilled water facilitates the reaction of the short-lived cation radical intermediates formed by C- C coupling or C-0 coupling reactions on the cathode surface leading to hydrolysis and -Xylcnc and other VAPs formation with high specificity and selectivity.

[0049] In preferred embodiments of the present disclosure, the catalyst initiator mixture can be the following combinations:

[0050] - 60% by weight of MgCCh with 40% by weight of MgO.

[0051] - 60% by weight of a mixture of MgCCh and one or more of NaiCCh. K2CO3, NaHCCh. or KHCO3 with 40% by weight of MgO.

[0052] The method of electrocatalytic conversion of GHG into VAPs:

[0053] The method of electrocatalytic conversion of Green House Gas (GHG) emissions that include CO2, CH4 and N2 into -Xylcnc and other value-added products (VAPs) includes:

[0054] - adding deionised water to an electrocatalytic reactor vessel and dipping a cathode, and an anode in the deionised water, wherein the cathode includes a combination of a Steel electrode and one or more of a metallic Copper (Cu), a Cu-alloy, or a Cu-doped Ti mesh electrode; and the anode is selected from metallic Copper (Cu), Cu alloy, Ti Mesh, Cu-doped Ti Mesh, wherein the electrodes act as electrocatalyst;

[0055] - purging GHG that include CO2, CH4 and N2 into the deionised water in the reactor vessel from an external GHG source;

[0056] - applying current density to the cathode and anode through an external power source; wherein the power source set at voltage of up to 5V and current of up to 5A;

[0057] - adding a catalyst initiator to the deionised water in the reactor vessel forming an initiator solution; and

[0058] - adding a concentrated acid to the initiator solution in the reactor vessel with constant stirring to form an electrolytic reaction solution, which produces H2 gas in-situ from the electrolytic reaction solution on the cathode surface, wherein the applied current density initiates the C-C coupling or C-0 coupling reactions on the cathode surface forming short-lived cation radical intermediates, wherein the short-lived cation radical intermediates react among themselves, or the short-lived cation radical intermediates react with the in-situ produced H2 gas, or both, forming organic acid anions and alkoxides, wherein, on the anode, due to proton formation oxygen evolution occurs, wherein the evolved oxygen reacts with the cation radical resulting in its oxidization to form -Xylcnc and other value-added products (VAPs) such as benzene, toluene and substituted benzene, wherein, on the anode, when the anode contains Cu, dissolution of Cu occurs forming Cu2+ions, wherein, the organic acid anions and alkoxides react with the Cu2+ions forming metallorganic complexes; which further dissolutes in the presence of acid medium to form -Xylcnc and other value-added products (VAPs) such as benzene, toluene and substituted benzene.

[0059] The Cu-alloy for the electrodes can be selected from Cu / CuO, Cu / Ag, Cu / Ti, Cu / Pt, and Cu / Pd, wherein the alloying substance i.e., CuO, Ag, Ti, Pt, and Pd is present in an amount of less than or equal to 2.5% by weight.

[0060] In the Cu-doped Ti Mesh electrodes, the dopant Cu is present in an amount of less than or equal to 2% by weight.

[0061] The concentrated acid added to the initiator solution in the reactor vessel is selected from HC1, H2SO4, HNO3, H3PO4.

[0062] In an aspect, the purging of GHG into the reactor vessel from an external GHG source is at a flow rate of 30-50 Litre / hour (LPH).

[0063] An external power of 1 to 5 W (current of 1 to 5 A at a voltage 1 to 5 V) was applied to the electrodes for substantial amount of time for the completion of the reaction, which facilitates the formation of organic cation radical intermediates, which lead to the formation of - Xylene as the major product and other VAPs.

[0064] The application of the current density is continued for a sufficient time for completion of the reaction. In an aspect, application of current density is continued for 3 to 5 hours to achieve good yield of p-Xylcnc.

[0065] In an aspect, aliquots of the concentrated acid is added to the reaction solution in regular intervals during the reaction process to continue the generation of in-situ hydrogen gas until the completion of the reaction.

[0066] The Faradaic Efficiency (FE%) of methane and GHG conversion with specificity to -Xylcnc by the method of the present disclosure is about 80%.

[0067] The plausible mechanisms of formation of the VAPs have been provided in Fig. 5.

[0068] Examples:

[0069] The present disclosure will now be explained in further detail by the following examples. These examples are illustrative of certain embodiments of the disclosure without limiting the scope of the present disclosure.

[0070] Electrocatalytic reactor details used in all the examples:

[0071] As the representation shown in Fig. 1, the electrocatalytic reactor vessel of capacity 150 litres with applied current and voltage. An inlet is provided on the cap of the reactor is the provision to pass GHG. The electrodes are in form of a slab with rectangular handle. The handle of the electrode acts as the current collector that is connected to the power source (PS). The dimensions of the slab of each electrode is 60cm* 15cm*0.1cm (length*breadth*thickness).

[0072] The power source (from Won-a-Tech, Korea) with 20 V and 10 A capacity. The power source is provided with software interface to acquire the dynamic data of the voltage (V) and Current (I) during the course of the reaction. The electrodes are connected to the power source via cables (one terminal acts as anode, and the other acts as cathode).

[0073] The ratio of the ingredients in the catalyst initiator mixture used in all the examples are by their weight percentage.

[0074] Example 1

[0075] Reduction of GHG emissions involving symmetric Copper or Copper alloy electrodes in Cone. HC1 medium.

[0076] - Feed source: GHG emissions collected from natural gas well.

[0077] - GHG Feed includes: CO2, CH4 and N2.

[0078] - Electrocatalytic reactor capacity: 150 litres.

[0079] - Cathode: Cu plate.

[0080] - Anode: Cu plate.

[0081] - Catalyst initiator: 60% MgCOs with 40% MgO in distilled water.

[0082] - Flow rate of GHG: 50LPH.

[0083] The electrocatalytic reactor was prepared according to the above specifications. The experiment was carried out at ambient of 28°C. 50 litres of deionised water was taken in the electrocatalytic reactor vessel, and the electrodes (cathode and anode) were dipped into the deionised water through the reactor lid. GHG was purged into the deionised water in the reactor vessel at a flow rate of 50LPH at 50 bar pressure. Current density was applied to the cathode and anode at an applied power of 10 W, wherein the utilized power at any instant of the reaction is 5 W. 150 gm of the catalyst initiator was added to deionised water to form the initiator solution, and the initiator solution was acidified with 100 ml Cone. HC1 to initiate generation of in-situ hydrogen gas by bulk electrocatalysis of acidified deionised water, and thereafter aliquots of 100 ml Cone. HC1 is added in every 30 mins until the completion of the reaction, which continues the generation of in-situ hydrogen gas to facilitate the reduction of GHG into -Xylcnc and other VAPs. Application of the current density across the electrodes was continued for 90 minutes. The completion of the reaction was noticed by light blue colour of the solution. After the completion of the reaction, the solution and solid products are analyzed by Gas chromatography-mass spectrometry (GC-MS).

[0084] Fig. 2 illustrates GC-MS spectra of the product solution obtained by the electrocatalytic reduction of GHG in Example 1.

[0085] The GC-MS of the reaction product indicates formation of p -Xylene as major product and benzene, substituted benzene, toluene and l,5-Hexadien-3-yne 2- methyl- 1,3,5-Cycloheptatriene as other products as shown in Table 1.

[0086] Table 1

[0087] From Table 1, it is inferred that approximately 46.64% of p-Xylene, 25% benzene and 10% substituted benzene are formed. Due to incomplete reaction, unsaturated hydrocarbon such as l,5-Hexadien-3-yne 2-methyl-l,3,5- Cycloheptatriene was formed, which amounts to 17%. Upon increasing the reaction time and electrocatalytic parameters, these minor products can be pushed to formation of p -Xylene of up to 85%. Example 2

[0088] Reduction of GHG emissions involving symmetric Copper or Copper alloy electrodes in Cone. H2SO4 medium.

[0089] - Feed source: GHG emissions collected from natural gas well.

[0090] - GHG Feed includes: CO2, CH4 and N2.

[0091] - Electrocatalytic reactor capacity: 150 litres.

[0092] - Cathode: Cu plate.

[0093] - Anode: Cu plate.

[0094] - Catalyst initiator: 60% MgCCh with 40% MgO in distilled water.

[0095] - Flow rate of GHG: 50 LPH.

[0096] The electrocatalytic reactor was prepared according to the above specifications. The experiment was carried out at ambient of 28°C. 50 litres of deionised water was taken in the electrocatalytic reactor vessel, and the electrodes (cathode and anode) were dipped into the deionised water through the reactor lid. GHG was purged into the deionised water in the reactor vessel at a flow rate of 50LPH at 50 bar pressure. Current density was applied to the cathode and anode at an applied power of 20 W, wherein the utilized power at any instant of the reaction is 5 W. 150 gms of the catalyst initiator was added to deionised water to form the initiator solution, and the initiator solution was acidified with 100 ml Cone. H2SO4 to initiate generation of in-situ hydrogen gas by bulk electrocatalysis of acidified deionised water, and thereafter aliquots of 100 ml Cone. H2SO4 is added in every 30 mins until the completion of the reaction, which continues the generation of in- situ hydrogen gas to facilitate the reduction of GHG into -Xylcnc and other VAPs. Application of the current density across the electrodes was continued for 90 minutes. The completion of the reaction was noticed by a colourless solution.

[0097] After the completion of the reaction, the solution and solid products are analyzed by Gas chromatography-mass spectrometry (GC-MS).

[0098] Fig. 3 illustrates GC-MS spectra of the product solution obtained by the electrocatalytic reduction of GHG in Example 2. The GC-MS of the reaction product indicates formation of p -Xylene as major product and benzene, substituted benzene, toluene and l,5-Hexadien-3-yne-2- methyl- 1,3,5-Cycloheptatriene as other products as shown in Table 2. Table 2

[0099] From Table 2, it is inferred that approximately 47.78% of p-Xylene, 14.26% benzene, 10% toluene and 23% substituted benzene are formed. Due to incomplete reaction, unsaturated hydrocarbons such as l,5-Hexadien-3-yne 2- methyl- 1, 3, 5-Cycloheptatriene, 1 -ethyl, 2-methyl cyclopropane around 1.71% &

[0100] 2.44% respectively are formed. Upon increasing the reaction time and electrocatalytic parameters, these minor products can be pushed to formation of p- Xylene of up to 85%. Example 3

[0101] Reduction of GHG emissions involving asymmetric Copper and Cu-doped Ti Mesh electrodes in Cone. HC1 medium. - Feed source: GHG emissions collected from natural gas well.

[0102] - GHG Feed includes: CO2, CH4 and N2.

[0103] - Electrocatalytic reactor capacity: 150 litres.

[0104] - Cathode: Cu plate.

[0105] - Anode: Cu-doped Ti Mesh.

[0106] - Catalyst initiator: 60% MgC'CL with 40% MgO in distilled water.

[0107] - Flow rate of GHG: 50 LPH.

[0108] The electrocatalytic reactor was prepared according to the above specifications. The experiment was carried out at ambient of 28°C. 50 litres of deionised water was taken in the electrocatalytic reactor vessel, and the electrodes (cathode and anode) were dipped into the deionised water through the reactor lid. GHG was purged into the deionised water in the reactor vessel at a flow rate of 50 LPH at 50 bar pressure. Current density was applied to the cathode and anode at an applied power of 20 W, wherein the utilized power at any instant of the reaction is 5 W. 150 gms of the catalyst initiator was added to deionised water to form the initiator solution, and the initiator solution was acidified with 100 ml Cone. HC1 to initiate generation of in-situ hydrogen gas by bulk electrocatalysis of acidified deionised water, and thereafter aliquots of 100 ml Cone. HC1 is added in every 30 mins until the completion of the reaction, which continues the generation of in-situ hydrogen gas to facilitate the reduction of GHG into -Xylcnc and other VAPs. Application of the current density across the electrodes was continued for 90 minutes. The completion of the reaction was noticed by a light blue colour solution.

[0109] After the completion of the reaction, the solution and solid products are analyzed by Gas chromatography-mass spectrometry (GC-MS).

[0110] Fig. 4 illustrates GC-MS spectra of the product solution obtained by the electrocatalytic reduction of GHG in Example 3.

[0111] The GC-MS of the reaction product indicates formation of p -Xylene as major product and benzene, substituted benzene, toluene and l,5-Hexadien-3-yne-2- methyl- 1,3,5-Cycloheptatriene as other products as shown in Table 3. Table 3

[0112] From Table 3, it is inferred that approximately 49.74% of p-Xylene, 19.02 % toluene and 11.30 % substituted benzene are formed. Due to incomplete reaction unsaturated hydrocarbon such as l,5-Hexadien-3-yne of about 19.95% is formed.

[0113] As observed, with the Cu-doped Ti Mesh and Cu electrodes combination, the electrocatalytic process archives the yield of p-Xylene of about 50%.

[0114] Upon increasing the reaction time and electrocatalytic parameters, the minor products can be pushed to formation of p-Xylene of up to 85%.

[0115] Advantages:

[0116] The electrocatalytic reduction of GHG emissions of the present disclosure has the following non-limiting advantages.

[0117] - The air-polluting GHG emission converted into p-Xylene and other useful raw material for industries.

[0118] - VAPs produced is the prime and vital constituent in the paint, varnish, chemical industries, thus the demand is high, which can be availed at much lesser cost compared to the current market price.

[0119] - Carbon credits from industries towards carbon neutral.

[0120] - The electrodes as electrocatalyst employed is an earth abundant material and hence highly cost effective. - Recycling of the electrode and electrocatalyst is highly feasible and facile making the process highly closed loop.

[0121] - Completely renewables driven - zero waste concept with 5R compliance.

[0122] - Flow type electrocatalytic reactor design leads to high selectivity and yield of production of VAPs.

[0123] - Excellent Faradaic efficiency (FE) of the process, leading to good yield of -Xylcnc, thus highly economical.

[0124] - To process tonnes of GHG per day, continuous flow electrocatalytic reactor can be designed with ease and hence scaling up and mass production is highly feasible

[0125] - Fess chemical intensive process, easy design and operation.

[0126] Applications:

[0127] The electrocatalytic reduction of GHG emissions of the present disclosure has the following non-limiting industrial applications.

[0128] - Production of VAPs such as -Xylcnc as the major product, and benzene, toluene and substituted benzene as the minor products.

[0129] - Vital constituent in the paint, varnish, chemical industries.

[0130] Although the present disclosure is described in terms of one or more embodiments, it is to be understood that they have been presented by way of example, and are not limiting. Thus, the present disclosure should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

Claims

CLAIMS1. An electrocatalytic reactor for conversion of Green House Gas (GHG) emissions that include CO2, CH4 and N2 into -Xylcnc and other value-added products (VAPs) comprising: symmetric or asymmetric electrodes (cathode and anode), wherein the cathode is selected from metallic Copper (Cu), Cu- alloy, or Cu-doped Ti mesh; and the anode is selected from metallic Copper (Cu), Cu alloy, Ti Mesh, Cu-doped Ti Mesh, wherein the electrodes act as electrocatalyst, and acidified deionised water (H3O+) as electrolyte for generation of H2 gas through bulk electrocatalysis, wherein a catalyst initiator is included in the acidified deionised water (H3O+), wherein an external current of 1 to 5 A is applied to the electrodes in a voltage range of 1 to 5 V, which initiates C-C coupling or C-0 coupling reactions on the cathode surface forming short-lived cation radical intermediates, wherein the short-lived cation radical intermediates react among themselves, or the short-lived cation radical intermediates react with the in-situ produced H2 gas, or both, leading to the formation of -Xylcnc and other VAPs, wherein the other VAPs include benzene, toluene and substituted benzene.

2. The electrocatalytic reactor as claimed in claim 1, wherein Cu-alloy for the electrodes can be selected from Cu / CuO, Cu / Ag, Cu / Ti, Cu / Pt, and Cu / Pd, wherein the alloying substance i.e., CuO, Ag, Ti, Pt, and Pd is present in an amount of less than or equal to 2.5% by weight.

3. The electrocatalytic reactor as claimed in claim 1, wherein in the Cu-doped Ti Mesh electrodes, the dopant Cu is present in an amount of less than or equal to 2% by weight.

4. The electrocatalytic reactor as claimed in claim 1, wherein the concentrated acid added to the initiator solution in the reactor vessel is selected from HC1, H2SO4, HNO3, H3PO4.

5. The electrocatalytic reactor as claimed in claim 1, wherein the catalyst initiator mixture includes a mixture of 60% by weight of carbonates orbicarbonates of Mg or Na or a combination of carbonates and bicarbonates of Mg and Na with 40% by weight of MgO.

6. The electrocatalytic reactor as claimed in claim 1, wherein the catalyst initiator is a mixture of MgCCh and one or more of NaiCCh. K2CO3, NaHCCh, or KHCO3 with 40% by weight of MgO.

7. A method of electrocatalytic conversion of Green House Gas (GHG) emissions that include CO2, CH4 and N2 into -Xylcnc and other value-added products (VAPs) includes the steps of:- adding deionised water to an electrocatalytic reactor vessel and dipping a cathode, and an anode in the deionised water, wherein the cathode includes a combination of a Steel electrode and one or more of a metallic Copper (Cu), a Cu-alloy, or a Cu-doped Ti mesh electrode; and the anode is selected from metallic Copper (Cu), Cu alloy, Ti Mesh, Cu-doped Ti Mesh, wherein the electrodes act as electrocatalyst;- purging GHG that includes CO2, CH4 and N2 into the deionised water in the reactor vessel from an external GHG source;- applying current density to the cathode and anode through an external power source; wherein the power source set at a voltage of IV to 5V and current of 1A to 5A;- adding a catalyst initiator to the deionised water in the reactor vessel forming an initiator solution; and- adding a concentrated acid to the initiator solution in the reactor vessel with constant stirring to form an electrolytic reaction solution, which produces H2 gas in-situ from the electrolytic reaction solution on the cathode surface, wherein the applied current density initiates the C-C coupling or C-0 coupling reactions on the cathode surface forming short-lived cation radical intermediates, wherein the short-lived cation radical intermediates react among themselves, or the short-lived cation radical intermediates react with the in-situ produced H2 gas, or both, forming organic acid anions and alkoxides,wherein, on the anode, due to proton formation, oxygen evolution occurs, wherein the evolved oxygen reacts with the cation radical resulting in its oxidization to form -Xylcnc and other value-added products (VAPs) such as benzene, toluene and substituted benzene, wherein, on the anode, when the anode contains Cu, dissolution of Cu occurs forming Cu2+ions, wherein, the organic acid anions and alkoxides react with the Cu2+ions forming metallorganic complexes; which dissolutes to form -Xylcnc and other value-added products (VAPs), wherein the other VAPs include benzene, toluene and substituted benzene.

8. The method as claimed in claim 7, wherein the reactor vessel is enabled to act as the steel cathode by applying current density to the reactor vessel.

9. The method as claimed in claim 7, wherein the reactor vessel is a doublewalled reactor vessel, wherein the inner wall that comes in direct contact with the reaction solution is made of mild steel, and the outer wall is made of Stainless Steel (SS), wherein the inner mild steel wall of the reactor vessel is enabled to act as the steel cathode by applying current density to the reactor vessel.

10. The method as claimed in claim 7, wherein aliquots of the concentrated acid is added to the reaction solution in regular intervals during the reaction process to continue the generation of in-situ hydrogen gas until the completion of the reaction.

11. The method as claimed in claim 7, wherein the application of the current density is continued for 3 to 5 hours.

12. The method as claimed in claim 7 operates at ambient temperature, and 1 atm pressure.

13. The method as claimed in claim 7, wherein Cu-alloy for the electrodes can be selected from Cu / CuO, Cu / Ag, Cu / Ti, Cu / Pt, and Cu / Pd, wherein the alloying substance i.e., CuO, Ag, Ti, Pt, and Pd is present in an amount of less than or equal to 2.5% by weight.

14. The method as claimed in claim 7, wherein in the Cu-doped Ti Mesh electrodes, the dopant Cu is present in an amount of less than or equal to 2% by weight.

15. The method as claimed in claim 7, wherein the concentrated acid added to the initiator solution in the reactor vessel is selected from HC1, H2SO4, HNO3, H3PO4.

16. The method as claimed in claim 7, wherein the catalyst initiator mixture includes a mixture of 60% by weight of carbonates or bicarbonates of Mg or Na or a combination of carbonates and bicarbonates of Mg and Na with 40% by weight of MgO.

17. The electrocatalytic reactor as claimed in claim 7, wherein the catalyst initiator is a mixture of MgCCh and one or more of Na2CC>3, K2CO3, NaHCCh. or KHCO3 with 40% by weight of MgO.

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