ELECTROCATALYTIC METHOD AND APPARATUS FOR THE SIMULTANEOUS CONVERSION OF METHANE AND CO2 TO METHANOL THROUGH AN ELECTROCHEMICAL REACTOR OPERATING AT ORDINARY TEMPERATURES AND PRESSURES, INCLUDING AMBIENT ONES

Abstract

Electrocatalytic apparatus for the simultaneous conversion of methane and CO.sub.2 into methanol via an elctrochemical reactor operating at ambient temperature and pressure, said electrochemical reactor simultaneously converts CO.sub.2 to methanol by surficial catalytic reaction on the cathode, and methane to methanol by surficial catalytic reaction on the anode. The electrochemical reactor futher works with an electrolyte consisting of electrolytic complexes of water-soluable transition metals and small molecules as co-catalyst of the electrocatalytic reactions and facilitator of ionic transfer and solubility of CO.sub.2 and CH.sub.4 molecules in the electrolyte. The electrochemical reactor is further equipped with zero-gap membrane electrocatalytic electrode assemlics, the cathode and anode comprising two electrocatalytic mesoporous surfaces and being tubular and coaxial, delineating two regions, which are separated one from the other by an ion exchange membrane (27). The tubular electrodes pack vertically together, the external gaps being filled by an insulating material. The packed electrodes are electronically connected to the power source in a parallel electrical circuit.

Claims

1. Electrocatalytic apparatus for the simultaneous conversion of methane and CO.sub.2 into methanol via an electrochemical reactor operating at standard ambient temperature and pressure, consisting of: electrochemical reactor; feeder for transformation of raw materials; transfer of the products to be transformed and of the product obtained from the transformation process, and characterized by the fact that the electrocatalytic reactor (FIG. 1), in which CO.sub.2 and methane flow from the outside: simultaneously, converts to methanol: CO.sub.2 by surficial catalytic reaction on the cathode, and methane, by surficial catalytic reaction on the anode; works with an electrolyte consisting of an aqueous solution of redox mediators and ionic fractions to control the electrochemical neutrality and pH of the reaction medium, in addition, it consists of electrolytic complexes of water-soluble transition metals and small molecules as co-catalyst of the electrocatalytic reactions and facilitator of ionic transfer and solubility of CO.sub.2 and CH.sub.4 molecules in the electrolyte; is equipped with zero-gap membrane electrocatalytic electrodes in which the reaction takes place consisting of two electrocatalytic mesoporous surfaces of electrode, cathode and anode, tubular and coaxial delineating two regions electrocatalytic: “catholyte” and “anolyte” (FIGS. 26, 28), which are separated one from the other by an ion exchange membrane (27). the tubular electrodes pack vertically together without any gap (the external gaps fills by insulating material). The packed electrodes electrically connect to the power source in a parallel electrical circuit in which the anode and cathode parts of each electrode connect to the anode and cathode of other packed electrodes, respectively and the final joint of anodes and cathodes connect to the power source. the electrolyte enters from down part of vertical electrodes and fluid through mesoscopic structure of both cathode and anode surfaces of the packed electrodes and exit from top side of the packed electrodes. the feed gas mixture including but not limited to mixture of methane and CO.sub.2 blows into the bottom of the reactor and both gaseous molecules physically dissolve in the electrolyte and fluid through mesoscopic part of vertical electrodes.

2. Apparatus, as in the previous claim, characterized in that the cathodic part, “catholyte”, is formed by layered deposition (FIG. 3) of semiconductor films of the p-type and/or conductive electroactive nanocomposites on a conductive surface so that the layer structure has a high affinity to capture of CO.sub.2 on the surfaces, an amplification effect on the received polarization potential, minimize the required energy for surficial, direct and selective reduction of adsorbed CO.sub.2 to methanol; is permeable to pass dissolved gas and electrolyte on both top and bottom sides: a decorated nanocomposites structure (FIG. 4) of fully earth abundant elements consists of well combination of 3D nanostructures with 2D top layers and immobilized molecular catalysts, uses as precursor of the mesoscopic films of the cathode surface. the 3D part of the decorated nanocomposites consists of earth-abundant elements in the structures including but not limited to, metal oxides, metal sulfides, metal nitrides, polyoxomethalates, aluminosilicates, metal organic frameworks, zeolitic imidazolate frameworks and hybrid organic-inorganic materials. the 2D part of the decorated nanocomposites consists of earth-abundant materials in the structures including but not limited to, 2D transition metals carbides and nitrides (MXenes), organic polymers and co-polymers, inorganic polymers, grapheme or other 2D allotropes of carbon, carbon nanotubes (CNTs), 2D metal oxides and 2D metal sulfides. the immobilized molecular catalysts on top of 3D/2D decorated nanocomposites consist of earth-abundant compounds in the structures including but not limited to, metal complexes, small organic molecules and biomolecules. the first layer deposits as a compact nanoscale thicknesses (40-150 nm) and subsequently one or two mesoporous layers of the decorated nanocomposites materials deposits on the compact layer with microscale thicknesses (0.5-8 .Math.m). the decorated layer of the nanocomposites when deposits as cathode surface can support polarization-induced piezopotential in addition a piezoelectrocatalytic effect to finally create a piezoelectrocatalyst in order to favour band bending and charge transfer kinetics of the electrode by using the piezopotential that create by electrolyte fluid through the mesoporous structure of the electrodes. in the cathodic region, by applying the bias potential from electric source the decorated 3D/2D/molecular multilayer structure of the cathodic piezoelectrocatalysts catalyze selective reduction of the CO.sub.2 to methanol through a surficial reaction mechanism via formation of H*, CO* and CH.sub.30* active intermediate moieties from H.sub.2O and CO.sub.2 molecules on the cathode surface. the cathodic surficial conversion of CO.sub.2 to methanol effectively takes place at standard ambient temperature and pressure.

3. Apparatus, as in the preceding claims, characterized in that the anodic part, “anolyte”, is formed by layered deposition (FIG. 3) of semiconductor films of the n-type and/or conductive electroactive nanocomposites on a conductive surface so that the structure of the layer has a high affinity to capture of methane on the surfaces, an amplification effect on the received polarization potential, minimizes the required energy for surficial, direct and selective oxidation of adsorbed methane to methanol and is permeable to pass gas and electrolyte on both top and bottom sides. a decorated nanocomposites structure (FIG. 4) of fully earth abundant elements consists of well combination of 3D nanostructures with 2D top layers and immobilized molecular catalysts, uses as precursor of the mesoscopic films of the anode surface. the 3D part of the decorated nanocomposites consists of earth-abundant elements in the structures including but not limited to, metal oxides, metal sulfides, metal nitrides, polyoxomethalates, aluminosilicates, metal organic frameworks, zeolitic imidazolate frameworks and hybrid organic-inorganic materials. the 2D part of the decorated nanocomposites consists of earth-abundant materials in the structures including but not limited to, 2D transition metals carbides and nitrides (MXenes), organic polymers and co-polymers, inorganic polymers, graphene or other 2D allotropes of carbon, carbon nanotubes (CNTs), 2D metal oxides and 2D metal sulfides. the immobilized molecular catalysts on top of 3D/2D decorated nanocomposites consist of earth-abundant compounds in the structures including but not limited to, metal complexes, small organic molecules and biomolecules. the first layer deposits as a compact nanoscale thicknesses (40-150 nm) and subsequently one or two mesoporous layers of the decorated nanocomposites materials deposits on the compact layer with microscale thicknesses (0.5-8 .Math.m). the decorated layer of the nanocomposites when deposits as anode surface can support polarization-induced piezopotential in addition a piezoelectrocatalytic effect to finally create a piezoelectrocatalyst in order to favour band bending and charge transfer kinetics of the electrode by using the piezopotential that create by electrolyte fluid through the mesoporous structure of the electrodes. in the anodic region, by applying the bias potential from electric source the decorated 3D/2D/molecular multilayer structure of the anodic piezoelectrocatalysts catalyze selective oxidation of methane to methanol through a surficial reaction mechanism via formation of OH* and/or other active oxygen molecules, and CH.sub.3* active intermediate moieties from H.sub.2O and CH.sub.4 molecules on the anode surface. the anodic surficial conversion of CH.sub.4 to methanol is effectively take place at standard ambient temperature and pressure.

4. Apparatus, as in the preceding claims, characterized by a feeding system: electrolyte, reaction components, methane and CO.sub.2 to be transformed, as well as extraction of the methanol produced, which consists of (FIG. 1): a. a flow line of the gaseous feedstocks including methane and CO.sub.2 or any mixture of methane/CO.sub.2 or any mixture of methane and CO.sub.2 with other gaseous species and vaporized water and other chemical contents, which is injected and passed through the pressure regulator 11, the flow regulator 12 and the gas sensor 13 and blown to the reactor through the flow line 17; b. the gaseous molecules mix with and/or dissolve in the aqueous electrolyte and flow from bottom to the top of the packed electrodes via diffusion through mesoporous cathodic and anodic regions of the packed electrodes; c. a flow line 18 containing possible formed vaporized methanol, transfer to the storage tank 9 through the line 20 after the liquefaction step in the condenser 14; d. the vapor phase of the condenser 14 consists of possible unreacted CO.sub.2 and CH.sub.4 molecules, bypass to the reactor through line 19, passing a one-way valve 15; e. pump 6, lines 21 and 22 which carry out the circulation of the electrolyte in the reactor; f. any mixture of water including but not limited to the sea water, waste water from residential and industrial and agricultural sewage and fresh water from rivers and underground sources and dehumidification of atmospheric moisture, insert in the electrolyte reservoir 25; g. the produced methanol in the liquid phase separate from the aqueous phase via passing the electrolyte through a methanol separation membrane 7 and transferred to the methanol storage tank 8 through the line 23; h. the methanol separation membrane 7 consists of two pervaporation hallow fiber membranes selective to methanol and water included but not limited to organic and/or inorganic polymers composited with 2D MXenes nanoflakes or 3D inorganic catalysts like zeolites and polyoxomethalates.

Description

[0025] The invention will be described with reference to the attached table where:

[0026] FIG. 1 represents the apparatus that carries out the transformation method of methane and CO.sub.2 in methanol with the reactor where the transformation takes place and the components for feeding the reagents, the electrolyte and the extraction of methanol,

[0027] FIGS. 2, 3 and 4 details of the structure and mutual positioning of the electrodes and decorated nanocomposites.

[0028] The reactor of the present invention consists of electrodes connected in parallel and each electrode consists of two electrocatalytic regions, i.e. the catholyte and the anolite, which are separated from each other by an ion-exchange membrane.

[0029] The core of each electrode consists of a cathode which is formed by a layer by layer deposition of at least, but not limited to (non-binding limit), 3 p-type semiconductor films and / or conductive electro-active nanocomposites on a conductive surface.

[0030] A decorated (well combination of 3D nanostructures with 2D top layers and immobilized molecular catalysts) nanocomposites structure of fully earth abundant elements (not utilization of any amounts of rare-elements e.g., platinum, ruthenium, iridium, etc), are used as precursor of the p-type semiconductor films of cathode.

[0031] The 3D part of the decorated nanocomposites consists of earth-abundant elements including iron, copper, zinc, titanium, tungsten, zirconium, silicon, carbon and molybdenum in the structures including but not limited to, metal oxides, metal sulfides, metal nitrides, polyoxomethalates, aluminosilicates, metal organic frameworks, zeolitic imidazolate frameworks, hybrid organic-inorganic materials.

[0032] The 2D part of the decorated nanocomposites consists of earth-abundant materials including iron, copper, zinc, titanium, tungsten, zirconium, silicon, carbon and molybdenum in the structures including but not limited to, 2D transition metals carbides and nitrides (MXenes), organic polymers and co-polymers, inorganic polymers, grapheme or other 2D allotropes of carbon, carbon nanotubes (CNTs), 2D metal oxides and/or 2D metal sulfides.

[0033] The immobilized molecular catalysts on top of 3D/2D decorated nanocomposites consists of earth-abundant compounds in the structures including but not limited to, metal complexes, biomolecules and small organic molecules.

[0034] For example, the decorated 3D/2D/molecular nanocomposites may consist of polyoxometalates of the type Si/Mo/W/Cu, CuO/ZnO, ZnFe.sub.2O.sub.4, ZnCO.sub.2O.sub.3, natural doped aluminosilicates with polymers, carbon-doped carbon fibers, imidazolate zeolitic structures (ZIF), immobilized and modified enzymes, MXenes, structured phase of some oxides/sulphides/metal nitrides such as WO.sub.3, ZnS, TiN, TiO.sub.2, SnO.sub.2 and FeS.

[0035] The layers are formed from inks and/or pastes and/or powders formulated from the decorated nanocomposites through different techniques including, but not limited to, dip-coating, sputtering, chemical vapor deposition, physical vapor deposition, blade coating, slot-die coating, spray coating, spray pyrolysis, magnetron sputtering, atomic layer deposition, chemical bath deposition, co-precipitation, hot pressing, powder coating, brush coating, sol-gel, electrochemical coating, self-assembly, mechanical stacking, photocatalytic formation and biocatalytic formation.

[0036] The first layer deposits as a compact nanoscale thicknesses (40-150 nm) and subsequently one or two mesoporous layers of the decorated nanocomposites materials deposits on the compact layer with microscale thicknesses (0.5-8 .Math.m). The decorated layer of the nanocomposites when deposits as mesoporous cathode surface can support polarization-induced piezopotential in addition a piezoelectrocatalytic effect to finally create a piezoelectrocatalyst in order to favour band bending and charge transfer kinetics of the electrode by using the piezopotential that create by electrolyte fluid through the mesoporous structure of the electrodes. In the piezoelectrocatalyst, external strain can generate a spontaneous internal electric field due to the presence of polarized charges. The surface energy level with positive polarization charge is downward bent throughout the domain, such that the surface will be at a higher potential compared with before. This case is beneficial for electron migration to the electrolyte, and its reduction ability is further enhanced. By contrast, with negative polarization charges, a potential is gained across the domain and the band is upward bent, thus the surface is at a lower potential than before. And in this case, the transfer kinetics of electroinduced electrons is suppressed for the increased energy barrier, while the hole transfer will be facilitated (but slightly reduces the reduction potential). In total, determined by the strength of internal electric field, different degrees of band bending obtained by tuning the direction/strength of applied strain can result in varied transfer kinetics of surface charges. Meanwhile the driving force (redox potential of charges) toward the surficial cathode reaction (reduction of CO.sub.2 to methanol at surface of the cathode) in the electrolyte solution can also be manipulated.

[0037] The working functions of the porous layers in the cathodic part of the electrode are optimized to minimize the required electrical power of the redox reaction. The band structure of each layer is engineered to amplify the potential applicator and reduce the barrier to the electrochemical reaction by minimizing the activation energy of the rate determination step.

[0038] In the cathodic region, by applying the bias potential from electric source the decorated 3D/2D/molecular multilayer structure of the cathodic piezoelectrocatalysts catalyze selective reduction of the CO.sub.2 to methanol through following surficial reaction mechanism:

##STR1)##

##STR2)##

##STR3)##

##STR4)##

[0039] In order to improve the selectivity of the reaction towards methanol, the active redox complexes of abundant transition metals use as a co-catalyst of the cathodic reaction.

[0040] The composition layer by layer of the films produces an amplification effect due to the bias potential of performing the reaction under environmental conditions and low electrical power with high conversion efficiency.

[0041] The composition of the anode part of the electrode contains electro-active nanocomposites of the n-type semiconductor and conductor of at least, but not limited to, 3 films of earth-abundant elements.

[0042] A decorated (well combination of 3D nanostructures with 2D top layers and immobilized molecular catalysts) nanocomposites structure of fully earth abundant elements are used as precursor of the n-type semiconductor films of anode.

[0043] The 3D part of the decorated nanocomposites consists of earth-abundant elements including iron, copper, zinc, titanium, tungsten, zirconium, silicon, carbon and molybdenum in the structures including but not limited to, metal oxides, metal sulfides, metal nitrides, polyoxomethalates, aluminosilicates, metal organic frameworks, zeolitic imidazolate frameworks, hybrid organic-inorganic materials.

[0044] The 2D part of the decorated nanocomposites consists of earth-abundant materials including iron, copper, zinc, titanium, tungsten, zirconium, silicon, carbon and molybdenum in the structures including but not limited to, 2D transition metals carbides and nitrides (MXenes), organic polymers and co-polymers, inorganic polymers, grapheme or other 2D allotropes of carbon, carbon nanotubes (CNTs), 2D metal oxides and/or 2D metal sulfides.

[0045] The immobilized molecular catalysts on top of 3D/2D decorated nanocomposites consists of earth-abundant compounds in the structures including but not limited to, metal complexes, biomolecules and small organic molecules.

[0046] The anode layers are formed from inks and/or pastes and/or powders formulated from the decorated nanocomposites through different techniques including, but not limited to, dip-coating, sputtering, chemical vapor deposition, physical vapor deposition, blade coating, slot-die coating, spray coating, spray pyrolysis, magnetron sputtering, atomic layer deposition, chemical bath deposition, co-precipitation, hot pressing, powder coating, brush coating, sol-gel, electrochemical coating, self-assembly, mechanical stacking, photocatalytic formation and biocatalytic formation.

[0047] For example, the decorated 3D/2D/molecular nanocomposites of anode can be made with Si/W/Co-based of n-type polyoxometalates, Co.sub.2O.sub.3/ZnO, Nb.sub.2O.sub.3, ZnSnO.sub.3, MnO.sub.2, NiO, ZnFe.sub.2O.sub.4, ZnCo.sub.2O.sub.3, vanadium oxide, inorganic perovskites such as CsPbX.sub.3, natural metal aluminosilicate metal structure, MOF and modified structured phase of some metal oxides/sulphides/nitrides such as WO.sub.3, TiN, TiO.sub.2, SnO.sub.2 and ZnS.

[0048] The first layer deposits as a compact nanoscale thicknesses (40-150 nm) and subsequently one or two mesoporous layers of the decorated nanocomposites materials deposits on the compact layer with microscale thicknesses (0.5-8 .Math.m).

[0049] Similar to the cathode, the decorated layer of the nanocomposites when deposits as mesoporous anode surface can support polarization-induced piezopotential in addition a piezoelectrocatalytic effect to finally create a piezoelectrocatalyst in order to favour band bending and charge transfer kinetics of the electrode by using the piezopotential that create by electrolyte fluid through the mesoporous structure of the electrodes. Accordingly, the driving force toward the surficial anode reaction (oxidation of methane to methanol at surface of the anode) in the electrolyte solution can also be manipulated. The working functions of the porous anode layers are aimed at minimizing the electrical power required for the oxidation reaction.

[0050] In the anodic region, by receiving the applied bias potential from electric source the decorated 3D/2D/molecular multilayer structure of the anodic piezoelectrocatalysts catalyze partial oxidation of the methane to methanol through following surficial reaction mechanism:

##STR1)##

##STR2)##

##STR3)##

[0051] The formed active oxygen fractions react immediately with methane molecules in the space charge region of the anode and produce methanol.

[0052] The selectivity of this reaction also improves by using hemogenious co-catalysts of earth-abundant transition metal complexes.

[0053] The working function of the anodic layers is aimed at amplifying the polarization potential and improving the faradic efficiency in ambient environmental conditions.

[0054] The electrolyte consists of an aqueous solution of redox mediators and ion fractions for the control of electrochemical neutrality and pH of the reaction solution, Some complexes of water-soluble transition metals, including, by way of example, Schiff bases of Cu/Co/Cr, salens, salophen, chelates and metallocenes, as co-catalyst of the electrocatalytic reaction. The co-catalysts acts three separate roles at the same time namely, i) enhancement the solubility of the CO.sub.2 and CH.sub.4 in aqueous solution, ii) electrochemical stable and fast redox scuttles to facilitate the ionic transport inside the electrochemical regions, and iii) enhancement the selectivity of the surficial reactions toward formation of CH.sub.3O* intermediate phase. However, the mentioned co-catalysts can also immobilized on the surface of the decorated 3D/2D piezoelectrocatalysts as well.

[0055] A threshold voltage of 0.8 V is required to start the electrochemical reaction and the total consumed electrical energy is relative to the reactor capacity.

[0056] A bipolar membrane consists of but not limited to organic and/or inorganic polymers composited with 2D MXenes nanoflakes installs between cathode and anode without any gap (zero-gap membrane structure) for maintain the electric neutrality of the reaction medium. Accordingly, the formed OH.sup.- and H.sup.+ ions in the catholyte and anolyte mesostructure, respectively, can migrate through bipolar ion-selective membrane to maintain electrical neutrality of the electrochemical system.

[0057] FIG. 1 represents the apparatus that carries out the overall transformation process for the feeding phases of the cylindrical reactor 1, which can be constructed, for example, in polyethylene or glass or stainless steel or any corrosion-resistive coated metals, to extract and store the produced methanol. [0058] The tubular electrodes 2 are arranged inside the reactor; [0059] The electrodes are connected in parallel to the electric jointer 3, which is connected to a potentiostat/galvanostatic instrument 4; [0060] The driving force of the electrochemical reaction is provided by a DC power source 5 through the wires 24; [0061] The electrodes are permeable to pass gas and electrolyte on both sides; [0062] Any type of gaseous raw material including atmospheric air, industrial CO.sub.2-rich air, pure CO.sub.2, natural gas, biogas and pure methane can be injected into the system through line 16 and using the compressor 10, individually and/or simultaneously as blend. The feed mixture can contain any gaseous (e.g., O.sub.2, CO, NO.sub.x, SO.sub.x, H.sub.2S, N.sub.2) and/or vaporized (e.g., H.sub.2O, mercaptans, hydrocarbons, solvents) moieties without any limitation; [0063] The injected flow line is passed through the pressure regulator 11, the flow regulator 12 and the gas sensor 13 and blows to the reactor and mix with the electrolyte through the flow line 17; [0064] The flow line 18 containing possible formed vaporized methanol, possible unreacted methane and CO.sub.2 and other possible gaseous moieties of the injected feed, flow in the condenser 14 which led to the liquefaction of the vaporized methanol and transfer to the methanol storage tank 9 through the line 20; [0065] On the other hand, the vapor phase of the condenser, bypasses into the system through line 19 passing through a one-way valve 15; [0066] The reactor electrolyte circulates from pump 6, line 21 and line 22; [0067] Any mixture of water including but not limited to the sea water, waste water from residential and industrial and agricultural sewage and fresh water from rivers and underground sources and dehumidification of atmospheric moisture, insert in the electrolyte reservoir 25;

[0068] The produced methanol in the liquid phase of the electrolyte is separated from the aqueous phase by the methanol separation membrane 7 and transferred to the methanol storage tank 8 through the line 23. The fresh electrolyte is stored in the storage tank 25 and injected into the reactor during production.

[0069] The methanol separation membrane 7 consists of two pervaporation hallow fiber membranes selective to methanol and water included but not limited to organic and/or inorganic polymers composited with 2D MXenes nanoflakes or 3D inorganic catalysts like zeolites and polyoxomethalates.

[0070] The internal structure of each packed tubular zero-gap membrane electrode is shown in FIG. 2. [0071] The core 26 is related to the cathode, which is formed by the deposition of at least 3 p-type decorated semiconductor mesoporous films on a conductive surface; The shell of the tubular electrode is structured by the anode 28, which is formed by the deposition of at least 3 n-type decorated semiconductor mesoporous films on a conductive surface; [0072] The cathode and the anode are separated by an ion exchange membrane 27 without any physical gap between electrodes and the membrane. The conductive parts of the anode and the cathode are connected to the electrical joint 3; [0073] The external surface of the anode covers by insulating coating 29. The tubular electrodes packed vertically together without any gap (the external gaps fills by insulating material). The packed electrodes electrically connect to the power source in a parallel electrical circuit in which the anode and cathode parts of each electrode connect to the anode and cathode of other packed electrodes, respectively and the final joint of anodes and cathodes connect to the power source.

[0074] The layer by layer structure of the tubular electrodes is shown in FIG. 3. [0075] The zero-gap membrane tubular electrode is consists of a rod-like compact core 30 of cathode substrate which covered by a nanoscale compact film 31 of an earth-abundant p-type semiconductor and subsequently one and/or two microscale mesoscopic porous films 32 and 33 composited by decorated earth-abundant piezoelectrocatalysts of the cathode. A microscale film of ion-selective membrane 34 covers cathode without any gap between cathode and internal surface of the membrane; [0076] The ion-selective membrane is designed by using of a composition of earth-abundant polymer/MXenes layers with bipolar structure and cation and anion exchange characteristic and non-permeability to methane and CO.sub.2 molecules; [0077] A tubular anode substrate 38 which consists of metallic flexible foil which internally covered by a nanoscale compact film 37 of a n-type semiconductor and subsequently one and/or two microscale mesoscopic porous films 35 and 36 composited by decorated earth-abundant piezoelectrocatalysts of the anode, cover on the ion-selective membrane 34 without any gap between anode and external surface of the ion-selective membrane; [0078] The electrolyte including the mixture of gaseous feedstocks enter from bottom part of vertical electrodes and fluid through mesoscopic structure of both cathode and anode.

[0079] The structure of the decorated nanocomposites which utilized as precursor of piezoelectrocatalysts in the mesoscopic layers of the cathode and anode is shown in FIG. 4. [0080] The decorated nanocomposites synthesize from fully earth abundant elements consists of a core 39 of 3D nanostructures which covered by a shell 40 of 2D nanostructures and immobilized molecular catalysts 41, uses as precursor of the mesoscopic films of the anode and cathode surfaces. The decorated 3D/2D/molecular structure of the nanocomposites can induce the piezoelectrocatalytic effect when deposit as mesoporous layers of cathode and anode surfaces. Furthermore, the decorated structure can markedly enhance the adsorption of the CO.sub.2 and CH.sub.4 molecules on the surface of cathode and anode, respectively. In addition, the decorated structure can improve the selectivity of the surficial reaction of CO.sub.2 and CH.sub.4 toward methanol (as a selective product) in the cathode and anode, respectively.

[0081] The performance of the process and of the apparatus described above (engineered) to subject it to different tests.

[0082] The design construction details adopted for carrying out the experimentation and showing the feasibility of the invention do not constitute a form of limitative embodiment of the method and of the related apparatus for which patent protection is requested.

[0083] It is used pure methane gas in capsules with a purity of 99% (sample M1), the natural residential distribution line with 80% of methane (sample M2) and biogas provided by the bacterial digestion of urban organic waste with about 60% of methane (sample M3) as methane-based raw materials. Furthermore, pure CO.sub.2 gas as a capsule with 99% purity (sample C1), concentrated CO.sub.2 flow from a cement production line with ∼ 75% CO.sub.2 (sample C2), a biogas flow from bacterial digestion of urban organic waste containing ∼ 40% CO.sub.2 (Sample C3) and normal atmospheric agricultural air containing ∼ 400 ppm of CO.sub.2 (sample C4), are used as carbon-based raw materials.

[0084] The quality and quantity of all the samples and gases contained are analyzed by sampling from the gas lines entering and leaving the reactor, using a portable gas analyzer with precise sensors for CO.sub.2, CH.sub.4, CO, H.sub.2, O.sub.2, N.sub.2, NO.sub.2 , SO.sub.2 and H.sub.2S. The quantities of methanol produced in the liquid phases are analyzed by GC-Mass analysis. The faradic response of the reactor is controlled through the reaction by means of a potentiostatlgalvanostate instrument and through chronopotentiocholometric (CPC) analysis.

[0085] The results of the electrocatalytic reaction are shown in the Table. The conversion is calculated based on the raw material for the incoming gas and the difference in the percentage of methane/CO.sub.2 in any supply is not considered.

TABLE-US-00001 Results of the electrocatalytic reaction for three methane-based samples and four CO.sub.2-based samples as feedstock of the reactor Number Sample Feed Conversion (%) Selectivity (%) Temperature (°C) Pressure (atm) Time (min) 1 M1 69 65 25 1 15 2 M1 88 83 25 1 30 3 M1 91 87 25 1 45 4 M1 93 91 25 1 60 5 M1 97 94 25 1 90 6 M2 38 35 25 1 15 7 M2 51 45 25 1 30 8 M2 59 54 25 1 45 9 M2 68 60 25 1 60 10 M2 75 64 25 1 90 11 M3 40 36 25 1 15 12 M3 47 42 25 1 30 13 M3 54 49 25 1 45 14 M3 62 52 25 1 60 15 M3 69 60 25 1 90 16 C1 34 30 25 1 15 17 C1 52 48 25 1 30 18 C1 67 59 25 1 45 19 C1 79 70 25 1 60 20 C1 96 91 25 1 90 21 C2 29 24 25 1 15 22 C2 48 39 25 1 30 23 C2 60 45 25 1 45 24 C2 73 56 25 1 60 25 C2 82 61 25 1 90 26 C3 30 22 25 1 15 27 C3 45 33 25 1 30 28 C3 51 39 25 1 45 29 C3 64 48 25 1 60 30 C3 71 55 25 1 90 31 C4 17 15 25 1 15 32 C4 29 25 25 1 30 33 C4 48 40 25 1 45 34 C4 60 52 25 1 60 35 C4 67 60 25 1 90

[0086] The results show a high conversion efficiency in environmental conditions both for methane and CO.sub.2 raw materials with a high selectivity of the electrocatalytic reaction toward methanol as a product.