Photoelectrochemical device for capturing, enriching and collecting atmospheric carbon dioxide

Abstract

The present invention relates to a photoelectrochemical device for capturing, enriching and collecting atmospheric carbon dioxide. Specifically, it relates to a carbon dioxide capture device comprising a first reactor and a second reactor, both of which exhibit an (photo)anode containing or connected to an oxygen evolution and / or carbon dioxide evolution catalyst and a (photo)cathode containing or connected to an oxygen reduction catalyst, wherein the first reactor includes an anion exchange membrane disposed between a porous (photo)anode and a porous (photo)cathode, and the second reactor includes a proton exchange membrane disposed between a porous (photo)anode and a porous (photo)cathode. There is a fluid inlet capable of transporting carbon dioxide, air and water on the porous (photo)cathode side of the first reactor, and a fluid outlet capable of transporting carbon dioxide and water on the porous (photo)cathode side of the second reactor.

Description

Technical Field

[0001] The present invention relates to a carbon dioxide capture device comprising a first reactor and a second reactor, both showing an (photo)anode containing or connected to an oxygen evolution and / or carbon dioxide evolution catalyst and a (photo)cathode containing or connected to an oxygen reduction catalyst, wherein the first reactor comprises an anion exchange membrane disposed between a porous (photo)anode and a porous (photo)cathode, and the second reactor comprises a proton exchange membrane disposed between a porous (photo)anode and a porous (photo)cathode. There is a fluid inlet capable of carrying carbon dioxide, air and water on the porous (photo)cathode side of the first reactor, and a fluid outlet capable of carrying carbon dioxide and water on the porous (photo)cathode side of the second reactor, and the device is configured to transfer the fluid leaving the porous (photo)cathode side of the first reactor to the porous (photo)anode side of the second reactor, and to transfer the fluid leaving the porous (photo)anode of the first reactor to the porous (photo)cathode side of the second reactor.

[0002] In a preferred embodiment of the present invention, the fluid involved in the fluid inlet flow is gaseous, namely water and carbon dioxide and oxygen captured from ambient air. Background Art

[0003] Anthropogenic carbon dioxide emissions are causing a global environmental crisis, such as an increased propensity for natural disasters (such as floods and droughts), massive ice melting leading to a rise in the average sea level, and the mass extinction of plants and animals that cannot evolve quickly enough to survive in the new climate conditions.

[0004] With the introduction of renewable power sources and improved energy efficiency, it is hoped that carbon dioxide levels will decline in the coming years. However, this alone is not sufficient to solve the climate crisis. In fact, recent reports from the International Panel on Climate Change indicate that carbon capture and storage - the capture of emitted carbon dioxide and its long-term storage (e.g., underground) - will play an important role in limiting the extent of global warming. Specifically, it will be necessary to capture and store 14% of carbon dioxide emissions in the 2°C scenario and 32% in the below 2°C scenario by 2050.

[0005] While the capture of enriched carbon dioxide solutions is well known and has been commercialized on a medium scale, there is now less response to carbon dioxide emitted from inevitable and non-enriched sources, such as transportation (currently), manufacturing with built-in carbon dioxide emissions that may need to be offset, and agriculture. The capture of non-enriched carbon dioxide is called direct air capture.

[0006] In the prior art, electrochemical direct air capture is disclosed in WO 2019 / 136374A1. Here, proton-coupled redox-active substances such as quinones, phenazines, phenoxazines, isoalloxazines, or polyoxometalates are used, and their protonation and deprotonation can be electrochemically controlled to change the pH of an aqueous solution or aqueous suspension. This change in pH can be used to sequester and release CO2. Alternatively, the oxidation and reduction cycles of amines, quinones, and other ionic liquids can be utilized. CO2 can be selectively bound and separated based on the oxidation state of the molecule, allowing for controlled capture and then release of the gas at the collection inlet.

[0007] Photoelectrochemical carbon dioxide capture is disclosed in US8791354B2. A redox mediator is used to transfer CO2 from one side of the device to the other through a liquid electrolyte (a non-aqueous solvent or ionic liquid). Instead of using electricity to transfer CO2 from an external source, light is used to generate charge in a semiconductor (although an external source can also be used, for example, at night). Then, this charge can be used to drive CO2 through the device. Additionally, when the CO2 inhibition is by-passed, the device can be used as a photovoltaic cell.

[0008] In addition to the amine cycle and (photo)electrochemical direct air capture of carbon dioxide as described above, membrane matrix methods are also known, as disclosed in US7993432B2, US2015 / 0165373A1, US2012 / 0220019A1, and US 10150112B2. A CO2 adsorbent is exposed to a gas mixture and allowed to adsorb CO2. The gas is then released from the adsorbent through a regeneration process to produce a gas-rich mixture, and then the CO2-rich gas mixture is contacted with an aqueous solution, which selectively absorbs CO2. The adsorbent material can be a solid-phase anion exchange membrane - an open matrix with a relatively large surface area (for air flow with minimal resistance) or coated on a carrier material such as a cellulose matrix.

[0009] Regarding CO2 capture devices, the current solutions are i energy-intensive, ii costly, and iii provide very little financial incentive for installation (except for avoiding future carbon taxes, and future costs are still uncertain).

[0010] Compared with electrochemical, membrane matrix, and amine cycle methods, it is desirable to provide an incentive concept for generating electricity in parallel with CO2 capture. Preferably, a solid-state device is proposed - to simplify installation and operation and avoid the use of exotic chemicals such as expensive and difficult-to-scale redox mediators. Summary of the Invention

[0011] The present invention described herein is a device for solar-driven direct air carbon dioxide capture and separation. It uses an anion exchange membrane to selectively capture carbon dioxide in the first reactor of the device, preferably using a bias-free current, and transfers it to a storage area on the other side of the first reactor of the device. Then, the second reactor of the device converts oxygen into water through a proton exchange membrane to facilitate the separation of carbon dioxide. Additionally, electricity is also provided by the device in parallel with carbon dioxide capture. It can be considered a photovoltaic device with carbon dioxide capture functionality. The device of the present invention can be used to capture CO2 from ambient air or point (enriched) sources. Capturing CO2 from ambient air is preferred because when the concentration is too high, the solar energy that can be generated per unit area can limit the transfer of CO2 from one side of the membrane to the other side.

[0012] Accordingly, the present invention describes a photoelectrochemical solid-state device for capturing and enriching CO2 through an anion exchange membrane via an oxidation and reduction cycle. Then, the enriched gas stream enters a second photoelectrochemical cell (reactor), which acts as a CO2 purifier by removing unwanted oxygen.

[0013] In this context, the present invention thus provides a carbon dioxide capture device, comprising:

[0014] (a) A first reactor comprising an anion exchange membrane disposed between a porous (photo)anode and a porous (photo)cathode, wherein the (photo)anode contains or is physically or electrically connected to an oxygen evolution and / or carbon dioxide evolution catalyst, and the (photo)cathode contains or is physically or electrically connected to an oxygen reduction catalyst;

[0015] (b) A second reactor comprising a proton exchange membrane disposed between a porous (photo)anode and a porous (photo)cathode, wherein the (photo)anode contains or is physically or electrically connected to an oxygen evolution catalyst, and the (photo)cathode contains or is physically or electrically connected to an oxygen reduction catalyst;

[0016] wherein the porous (photo)cathode of the first reactor has at least a fluid inlet capable of transporting carbon dioxide, air, and water, and the porous (photo)anode of the first reactor has at least a fluid inlet capable of transporting water and oxygen,

[0017] the porous (photo)cathode of the second reactor has at least a fluid outlet capable of transporting carbon dioxide and water, and the porous (photo)anode of the second reactor has at least a fluid outlet capable of transporting water and oxygen,

[0018] wherein the carbon dioxide capture device is configured to transfer the fluid leaving the porous (photo)cathode of the first reactor to the porous (photo)anode of the second reactor, and transfer the fluid leaving the porous (photo)anode of the first reactor to the porous (photo)cathode of the second reactor.

[0019] In a preferred embodiment, the anodes of the first and second reactors are both photoanodes. However, the light absorber may not be on the anode side that serves as the photoanode, but on the cathode side, in the combination of the anode and the photocathode of the first and second reactors. Alternatively, a combination of a photoanode and a photocathode may be used. For the first and second reactors, there should be at least one light absorber. Thus, a cathode-anode combination in which neither of them is a light absorber is not suitable, but other combinations are possible, such as photoanode-cathode, anode-photocathode, and photoanode-photocathode.

[0020] In the device of the present invention, in its various embodiments, all inlets can be inlets for liquids or gases. In a preferred embodiment, the incoming water comes from ambient air (humidity), and inlets suitable for gas transport are preferred. The appropriate outlets of the device of the present invention are also outlets that are particularly suitable for gas transport.

[0021] The (photo)electrodes for use in the present invention (as the porous (photo)cathode or porous (photo)anode of the first or second reactor) are advantageously deposited or grown on or supported by a porous electrically conductive carrier material. In the practice of the present invention, the porous electrically conductive carrier in particular provides the porous characteristics to the (photo)cathode or porous (photo)anode construct rather than to the (photo)cathode or porous (photo)anode material itself. Suitable (photo)electrode carrier materials for the porous (photo)cathode or porous (photo)anode of the first and / or second reactor are, for example, porous (e.g., mesh, felt, foam, cloth, paper) substrates related to carbon, titanium, tungsten, stainless steel, nickel, or electrically conductive oxides. Such porous carrier materials, which may also be referred to in the art as "gas diffusion electrodes", may suitably contain 10 to 90%, more preferably 30 to 80%, voids and preferably allow fluid penetration, particularly gas transfer. The porous carrier material may be, for example, in the form of a mesh or a felt. A mesh, a single-layer porous material, may exhibit 10 to 80% voids (open areas), preferably 20 - 60% voids. The surface area of the porous carrier material may suitably be from 10 to 1000 cm 2 per geometric area of 10 to 1000 cm 2within the range of (for felt). The porous carrier material may suitably exhibit a bulk layer thickness of 1 to 1000 microns, preferably 100 to 400 microns. In terms of the thickness of the photo-electrode, up to 5 microns, preferably at most 1 micron is usually appropriate. On such a porous carrier material, a (photo)cathode or (photo)anode material specially selected to promote the electrocatalytic reaction can be deposited, as will be described in more detail below. The thickness of the porous (photo)cathode or porous (photo)anode material can be less than 5 microns, more preferably less than 1 micron, for example about 300 nm. A suitable (co)catalyst material can be provided as a layer with a thickness preferably less than 200 nm, more preferably less than 50 nm. For the (photo)cathode or (photo)anode material, the (co)catalyst material can provide a performance gain of up to 100 times. The amount of the added (photo)electrode material specially selected to promote oxygen reduction or oxygen evolution and / or carbon dioxide evolution can generally be 1% by mass or less, compared to the mass of the porous carrier material, such as in the form of a mesh, felt, or foam, and the amount of the added (co)catalyst material will generally be less than the amount of the added material.

[0022] In the device of the present invention, there can be an electrically conductive line between the (photo)anode and (photo)cathode of the first and / or second reactor. This means that the (photo)anode and (photo)cathode of either reactor do not need to be close to each other - the (photo)cathode can be in different chambers, provided that it has an electrical connection. Most suitably, the (photo)anode and (photo)cathode are connected through an electrical contact (such as a wire) between them. The generated electricity can be used for a lamp or forced convection in the advantageous function of the device of the present invention. Brief Description of the Drawings

[0023] Figure 1 Shows a schematic diagram of the carbon dioxide (CO2) enrichment in the first reactor of the carbon dioxide capture device of the present invention, including a photo-cathode capable of performing an oxygen reduction reaction (ORR) and a photo-anode capable of performing an oxygen evolution reaction (OER) / carbon dioxide evolution reaction (CO2ER). Here, the symbol "h + " refers to a positive hole that absorbs electrons.

[0024] Figure 2 Shows the band gaps of various semiconductors, with the potentials of oxygen evolution and reduction represented by dashed lines - based on the reference Nanoscale Horiz., 2016, 1, 243 - 267.

[0025] Figure 3 Shows a schematic diagram of the carbon dioxide (CO2) separation in the second reactor of the carbon dioxide capture device of the present invention, which includes a (photo)cathode capable of performing an oxygen reduction reaction (ORR) and a photo-anode capable of performing an oxygen evolution reaction (OER).

[0026] Figure 4A A combined device configuration is shown, in which the capture and separation functions are combined into one device, which is shown here in an exemplary configuration as Figure 4A .

[0027] Figure 4B A combined device configuration is shown, in which the capture and separation functions are combined into one device, which is shown here in an exemplary configuration as Figure 4B .

[0028] Figure 5 Capture of carbon dioxide (CO2) by absorption in an anion exchange membrane is shown. In Figure 5 , light is irradiated from the (photo)anode side. In the case where only the photocathode (and the anode) is present, it is preferred to irradiate light from the opposite side.

[0029] Figure 6A Gas collected on the opposite side of the device is shown, and the part of the device involved is as Figure 6A shown.

[0030] Figure 6B Gas collected on the opposite side of the device is shown, and the result is in Figure 6B .

[0031] Figure 7A Experimental data on CO2 separation using the concept of the present invention is shown, and the part of the device involved is as Figure 7A shown.

[0032] Figure 7B Experimental data on CO2 separation using the concept of the present invention is shown, and the result is in Figure 7B .

[0033] Figure 8 Possible device structural elements that can be used within the present invention are shown. Detailed Description

[0034] The present invention relates to a device comprising two membrane reactors connected to each other. The reactors can be placed in various configurations, such as but not limited to next to each other or one on top of the other, if the first reactor is sufficiently transparent.

[0035] Among one or more advantages observable with respect to known carbon dioxide capture devices, the present invention can be seen to provide:

[0036] 1) An easily implementable stand-alone device; and / or

[0037] 2) A new method for separating O2 and CO2 by converting O2 to H2O (gas to liquid).

[0038] The present invention provides a new mechanism for transferring CO2 from an adsorbent to a collector through a continuous oxygen reduction / oxidation cycle. So far, (photo)electrochemical CO2 adsorption has been limited to ionic liquids, and redox mediators are usually expensive exotic materials. The present invention provides a mechanism for a simple solid-state device design that captures CO2 and simultaneously generates electricity - motivating its use. Additionally, a photoelectrochemical method for separating O2 / CO2 by converting O2 into H2O is proposed. The present invention designs:

[0039] i. Utilize the oxygen reduction and oxygen evolution reaction cycles to generate a bias-free current as a driving force for HCO3 - ions to pass through the anion exchange membrane.

[0040] ii. Utilize water to drive H + ions to pass through the proton exchange membrane.

[0041] iii. Use solar energy to drive the reaction, with parallel power generation in the same device (however, the present invention can also be powered or supported by an external power source).

[0042] The function of the first reactor is to remove CO2 from the atmosphere, which can ideally be directly removed from ambient air or alternatively from a concentrated solution such as KHCO3. In fact, in this alternative embodiment, the effort to capture CO2 in a liquid solution, for example, through the conversion of KOH → KHCO3, can be combined with the system integrated in the present invention to deduct CO2 from KHCO3 and enrich it particularly at the fluid outlet side of the photoanode of the first reactor (117).

[0043] The first reactor contains an anion exchange membrane placed between a porous (photo)anode and a porous (photo)cathode. The (photo)anode contains or is connected (physically or electrically) to an oxygen evolution and / or carbon dioxide evolution catalyst, while the (photo)cathode contains or is connected to an oxygen reduction catalyst. This can generate a bias-free current, where only photocurrent is generated by light irradiation and no applied potential bias is required. To effectively generate photocurrent from the photoelectrode, sunlight and an applied potential bias across the photoelectrode may be required. Its main function is to improve the charge separation between e - and h + However, applying a potential increases the degree of additional complexity. In an advantageous embodiment of the present invention, photocurrent can be generated only under light irradiation, i.e., no applied potential bias is required. The anion exchange membrane absorbs CO2 from the atmosphere through natural or forced convection to form HCO3 - ions. Forced convection can be carried out, for example, by using a fan or a pump to force / recirculate air through the device. The device can operate without forced convection, but this is a possible embodiment to accelerate CO2 adsorption within the anion exchange membrane. Under solar irradiation, under a bias-free current, HCO3- The other side of the ion forcing device, i.e., the OER and CO2ER fluid outlets of the photoanode of the first reactor (117). The collection step can be appropriately carried out mainly at night, but collection in parallel with the transfer step under sunlight irradiation ( Figure 1 ) is also possible. The mixture collected on the opposite side is a mixture of CO2 and O2, but preferably a higher concentration of CO2. The total overpotential loss for oxygen evolution and oxygen reduction is about 0.7 V, providing various materials with suitable bandgaps as potential photoanodes ( Figure 2 ).

[0044] In the present invention, suitable materials for the porous (photo)anodes (113, 213, 313, 413) of the first reactor (1) containing anion exchange membranes (AEMs) (112, 212, 312, 412) are n-type or p-type (photo)electrode materials compatible with the AEMs having suitable bandgaps (according to Figure 2 ). Examples include BiVO4, TiO2, WO3, which can be combined with a (photo)cathode to achieve OER / CO2ER and ORR potentials. TiO2 is a practical example for device fabrication, but the large bandgap of TiO2 basically limits the absorption of UV light. Materials with smaller bandgaps (where the conduction band (CB) and valence band (VB) are on either side of the OER / CO2ER and ORR reaction potentials) are advantageous. The smaller the bandgap, the higher the absorption of visible light will be possible, which allows significantly more energy to be used in practical applications. Materials with a bandgap of about 1.0 to 2.0 eV and a conduction band edge below about 0.7 eV (vs. NHE) and a valence band above 1.7 eV (vs. NHE) are suitable, where NHE (= normal hydrogen electrode) is the reference electrode and the potential of platinum in a 1M acid solution (pH = 0). Preferred materials for the porous (photo)anode of the first reactor (1) can be selected from: BiVO4, TaO x N y, LaTiO2N, BaTaO2N, SrTaO2N, WO3, CuWO4, Fe2O3, ZnFe2O4, TiO2. A particularly preferred list consists of: BiVO4, TiO2, WO3. A protective layer or co-catalyst (catalyst on the photoanode, the material can be the same) can enhance performance and / or provide chemical compatibility for the alkaline environment. The OER / CO2ER (co-)catalyst material of the porous (photo)anode (113, 213, 313, 413) of the first reactor (1) can suitably include a catalyst based on one or more of the following: (A) OER: Ni, Ni Raney, NiCo, NiFe, NiP, CoP, CoPi, SrCoO3, Ru, Mg, Ag, Au; (B) CO2ER: Ni, Ni Raney, LaNiO3, LaMnO3, Ag, Ru, Au, Pt, Pt3M where M = Ni, Co, Y, PtRu, Co, NiP, CoP, FeP, NiCo, NiMo, NiW (and oxides of all metals in this list). For CO2ER, these materials can be separate or supported on, for example, carbon. Protection can be provided by an outer coating such as TiO2. In addition, in the case of using TiO2 as the material of the porous photoanode, no co-catalyst is required - TiO2 is self-catalytic.

[0045] In the present invention, the suitable material of the porous (photo)anode (123, 223, 333, 423) of the second reactor (2) containing a proton exchange membrane (PEM) (122, 222, 322, 422) is not the same but similar to the material described for the porous (photo)anode of the first reactor above. In fact, the different environments of the two reactors give rise to different potential stability problems, and the membrane of reactor 1 is alkaline and the membrane of reactor 2 is acidic.

[0046] Therefore, the preferred materials for the porous (photo)anode of the second reactor (2) can be selected from: BiVO4, TaO x N y, LaTiO2N, BaTaO2N, CuWO4, WO3, TiO2. The protective layer or co - catalyst can enhance performance and / or provide chemical compatibility for the alkaline environment. The OER catalyst can advantageously include: Ir, Mg, Ru, Rh and their oxides (e.g., IrOx, RhOx), Pt, Pd, Au. The ORR catalyst can advantageously include: Ru, Au, Pt, Pt3M where M = Ni or Co or Y, PtRu, NiP, CoP, FeP, NiCo, NiMo, NiW. These can be used alone or loaded on, for example, carbon. The OER (co - ) catalyst material for the porous (photo) anode (123, 223, 323, 423) of the second reactor (2) can preferably include a catalyst based on: Ir, Mg and / or Ru. Protection can be provided by an outer coating such as TiO2. Additionally, in the case of using TiO2, no co - catalyst is required as TiO2 is self - catalytic.

[0047] In the present invention, the suitable material (112, 212, 312, 412) of the porous (photo) cathode (111, 211, 311, 411) of the first reactor (1) containing the anion exchange membrane (AEM) (112, 212, 312, 412) is generally a p - type (photo) electrode material compatible with the alkaline exchange membrane having a suitable bandgap and edge (according to Figure 2)). Examples of cathode materials include: Pt / C, Pt-Ru / C, Au / C, Ni / C, and Ni-felt, among which Pt and Pt-Ru / C are preferred. Materials with a band gap of about 1.0 to 2.0 eV and a conduction band edge lower than about 0.7 eV (Vs. NHE) and a valence band higher than about 1.7 eV (Vs. NHE) are suitable. The preferred materials for the porous (photo) cathode of the first reactor (1) can be selected from: Si, MoS2, MoSe2, WS2, GaP, CdS, CdSe, ZnSe, CuNbO4, PMPDI, InP, WSe2, ZnFe2O4, CuNbO3, PMPDI, Cu2O, g-C3N4, CIGS, CIGSe, CaFeO2, and / or CuFeO2. A protective layer or co-catalyst can enhance the performance. The ORR (co-) catalyst material for the porous (photo) cathode (111, 211, 311, 411) of the first reactor (1) can suitably include catalysts based on the following: Ni, Raney Ni, LaNiO3, LaMnO3, Ag, Ru, Au, Pt, Pt3M where M = Ni, Co, Y, PtRu, Co, NiP, CoP, FeP, NiCo, NiMo, NiW, Ir, Mg, Ru, Pt, Rh, and / or RhOx. Protection and / or chemical compatibility with the alkaline environment can be provided by an outer coating such as TiO2. Carbon is also a suitable cathode, but a catalyst such as platinum is required. The Pt / C cathode is usually 60:40 Pt:C (by weight).

[0048] In the present invention, the suitable materials for the porous (photo) cathode (121, 221, 321, 421) of the second reactor (2) containing a proton exchange membrane (PEM) (122, 222, 322, 422) are different but similar to those for the porous (photo) cathode of the first reactor (1) above. Thus, the preferred materials for the porous (photo) cathode of the second reactor (2) can be selected from: Si, MoS2, MoSe2, WS2, GaP, CdS, CdSe, ZnSe, CuNbO4, PMPDI, InP, WSe2, ZnFe2O4, CuNbO3, PMPDI, Cu2O, g-C3N4, CIGS, CIGSe, CaFeO2, and CuFeO2. A protective layer or co-catalyst can enhance the performance. The ORR (co-) catalyst materials for the porous (photo) cathode (121, 221, 321, 421) of the second reactor (2) can suitably include catalysts based on the following: Ru, Au, Pt, Pt3M where M = Ni, Co, Y, PtRu, NiP, CoP, FeP, NiCo, NiMo, and / or NiW. Protection can be ensured by an outer coating such as TiO2. Carbon is also a suitable cathode, but a catalyst such as platinum is required, and the Pt / C cathode is typically 60:40 Pt:C (by weight).

[0049] In the present invention, the anion exchange membrane (AEM) (112, 212, 312, 412) for the first reactor can suitably be: anion exchange membrane materials containing quaternary ammonium groups (such as those sold under the following trade names: FAA, A201, TM1, ) or low-density polyurethanes having quaternary ammonium groups; anion exchange membrane materials containing imidazolium or polybenzimidazole groups (such as those sold under the following trade names: ) or triamine- or diamine-crosslinked quaternized polysulfones. The preferred anion exchange membrane materials are anion exchange membrane materials containing quaternary ammonium groups, low-density polyurethanes having quaternary ammonium groups, or anion exchange membranes containing imidazolium or polybenzimidazole groups. A particularly preferred choice is to use an anion exchange membrane based on a material having vinylbenzyl chloride and imidazolium groups (such as the material sold under the trade name: ). Low-density polyethylene (LDPE) including grafted LDPE is another preferred embodiment of the anion exchange membrane (AEM) in the present invention.

[0050] The proton exchange membrane (PEM) (122, 222, 322, 422) for the second reactor is suitably based, for example, on polysulfonic acid materials, such as the names and Those that are commercially available. Other proton exchange membranes can be used. Generally speaking, the materials of the proton exchange membranes that can be used to implement the present invention can be perfluorocarbon sulfonic acid or polysulfonic acid polymers (such as those commercially available under the following names: -F, SX ), polybenzimidazole membranes (especially for possible high-temperature use), such as those commercially available under the following names: AM, ST, polyacrylic acid and hydrocarbon membranes (such as those commercially available under the following names: ST, P, E). The preferred materials of the proton exchange membranes are: perfluorocarbon sulfonic acid or polysulfonic acid polymers, or polyacrylic acid, and most preferably perfluorocarbon sulfonic acid or polysulfonic acid polymers.

[0051] In the present invention, the porous (photo)anode and / or porous (photo)cathode of the first or second reactor can be ionomer-coated, which can help increase the CO2 adsorption capacity. The ionomers used for such coatings can particularly include the ionomer materials mentioned above that are used as anion exchange membranes (AEMs) or proton exchange membranes (PEMs). In the first reactor (with AEM), the loading of the ionomer coating is preferably at most 50 mg / cm 2 , more preferably 0.5 to 10 mg / cm 2 . In the second reactor (with PEM), the loading of the ionomer coating is preferably at most 50 mg / cm 2 , more preferably 0.5 to 10 mg / cm 2 , more preferably 1.0 to 5.0 mg / cm 2 , for example, about 3.0 mg / cm 2 . The ionomer coating is not necessary for implementing the present invention, and for example, the ionomer coating of the porous (photo)anode and / or porous (photo)cathode of the second reactor does not require an ionomer coating such as that of the porous (photo)anode and / or porous (photo)cathode of the first reactor. In addition, the ionomers do not need to be the same on the (photo)anode and (photo)cathode sides of the first or second reactor, but this option is designed for the practice of the present invention.

[0052] The present invention provides a device that can be completely solid-state. Therefore, as Figure 1 shown, the bicarbonate HCO3 - anions can be generated in the absence of any liquid, while both the cathode and the anode are in the gaseous state. It can be noted here that for most ion exchange membrane materials, such as polysulfonic acid materials, including those sold under the name ), the membrane itself is hygroscopic. Therefore, in practice, there is water inside the membrane, which allows HCO3 -Flow. However, there may not be completely "liquid" water, and the membrane still retains a plastic-like / polymeric structure when hydrated. In the proper in-field use of the device of the present invention, the hydrated water can come from ambient humidity. However, in very dry conditions (low relative humidity, desert), additional liquid water may be required.

[0053] The function of the second reactor is to convert any remaining O2 in the CO2 / O2 mixture, which can be transferred through a pipeline into the second reactor and into water to facilitate the purification of CO2 (separation of liquid and gas). The second reactor includes a proton exchange membrane placed between a porous (photo)anode and a porous (photo)cathode. The (photo)anode is (physically or electrically) connected to an oxygen evolution catalyst, while the (photo)cathode is connected to an oxygen reduction catalyst ( Figure 3 ). The CO2 / water mixture can be easily separated and stored / used for other applications.

[0054] There is the possibility of combining the capture and separation functions into one device, for example, the two configurations shown in FIG. 4.

[0055] Thus, in the device of the exemplary embodiment shown in FIG. 4a, the present invention provides a carbon dioxide capture device, wherein:

[0056] - The porous (photo)cathode of the first reactor has a fluid inlet and a fluid outlet, both of which are capable of carrying carbon dioxide in air and water, and the porous (photo)anode of the first reactor has a fluid inlet and a fluid outlet, both of which are capable of carrying water and oxygen;

[0057] - The porous (photo)cathode of the second reactor has a fluid inlet and a fluid outlet, both of which are capable of carrying carbon dioxide, oxygen, and water, and the porous (photo)anode of the second reactor has a fluid inlet and a fluid outlet, both of which are capable of carrying water and oxygen,

[0058] wherein the fluid outlet of the porous (photo)cathode of the first reactor is fluidly connected to the fluid inlet of the porous (photo)anode of the second reactor, and the fluid outlet of the porous (photo)anode of the first reactor is fluidly connected to the fluid inlet of the porous (photo)cathode of the second reactor.

[0059] Thus, in the device of the exemplary embodiment shown in FIG. 4b, the present invention provides a carbon dioxide capture device, wherein:

[0060] The first and second reactors are placed in a consolidated block separated by a separator such that the porous (photo) cathode of the first reactor is located opposite and separated from the porous (photo) anode of the second reactor by the separator, and the porous (photo) anode of the first reactor is opposite and separated from the porous (photo) cathode of the second reactor by the separator, and a single fluid line including the fluid inlet of the porous (photo) cathode of the first reactor and the fluid outlet of the porous photoanode of the second reactor travels along one wall of the consolidated block, and another single fluid line including the fluid inlet of the porous (photo) anode of the first reactor and the fluid outlet of the porous (photo) cathode of the second reactor travels along another wall of the consolidated block, the two walls facing each other and both in contact with the separator.

[0061] The hashed boundary region in the middle in Figure 4b is the frame / space separating Reactors 1 and 2 (the first and second reactors). The basic function of the hashed boundary region is to avoid contact between the two reactors.

[0062] Operation example

[0063] In a suitable method for using the carbon dioxide capture device of the present invention, first, during the night, the anion exchange membrane absorbs CO2. After 15 hours, a membrane of this type absorbs approximately 95% of its CO2 capacity ( Figure 5 ), making it ideally suited for a day-night cycle with sunlight.

[0064] Then, light irradiation is started to enrich CO2. This generates charge (photocurrent - I (mA) - Figure 6), which drives ions through the anion exchange membrane ( Figure 1 ). The gas collected on the opposite side of the first reactor (Figure 6) is in a ratio of approximately 4:1 O2:CO2 (for comparison, ambient air is 2000:1 O2:CO2). As the gas is collected, CO2 is obtained in the fluid output, as shown at the bottom in Figure 1 as part of the gaseous mixture H2O, O2, and CO2.

[0065] Table 1

[0066] I (mA) OER (ppm) <![CDATA[CO2ER(ppm)]]> <![CDATA[Selectivity to CO2]]> Experiment 3 630 170 27％ Theory 3 560 1120 (35％)

[0067] Here, OER refers to a reaction (oxygen evolution reaction) and CO2 ER means CO2 evolution reaction. OER (ppm) refers to the oxygen level in the fluid outlet (117, 217) of the first reactor, and CO2 ER (ppm) refers to the CO2 level in the fluid outlet (117, 217) side of the first reactor.

[0068] Here, (OH is carried out with the following -) - Carbon dioxide capture and separation in the PEC cell:

[0069] - Inlet - cathode: 3% H2O + 400 ppm CO2 in He;

[0070] - Inlet - anode: > 3% H2O in He;

[0071] - Electrolyte: Grafted LDPE anion - exchange membrane. Here, LDPE is low - density polyethylene, and "electrolyte" is an anion - exchange membrane (AEM)

[0072] - Photoanode: TiO2 / Ti - felt (substrate)

[0073] - Cathode: Pt / C

[0074] - UV lamp: 7 mW cm -2 Intensity

[0075] - Pretreatment in carbon dioxide: overnight

[0076] Here, "(AEM) - PEC cell" refers to the first reactor containing an anion - exchange membrane. PEC stands for "photoelectrochemical". The second reactor is a (PEM) - PEC cell, which also contains an anion - exchange membrane.

[0077] The oxygen reduction reaction / CO2ER of different cathodes has been tested. Pt / Ru, Au, and Ni. Pt / Ru and Pt gave promising results and are considered in the preferred selection.

[0078] The next step is to convert O2 into H2O through the proton - exchange membrane, again through the oxygen reduction and oxygen evolution cycles ( Figure 3 ). Again, the reaction starts when light shines on the device to generate charge carriers, which drives H + ions through the membrane. When the light is turned on, a clear decrease in the O2 concentration can be seen.

[0079] Here, the following is used for oxygen purification in the PEM (H + ) - PEC cell:

[0080] - Inlet - anode: 3% H2O + 500 ppm CO2 + 500 ppm O2 in He;

[0081] - Inlet - cathode: 2% H2O;

[0082] - Flow rate: 50 sccm (standard cubic centimeters per minute)

[0083] - Electrolyte: Proton - exchange membrane (PEM)

[0084] - Photoanode: TiO2 / Ti-Felt, ion-coated

[0085] - Cathode: Pt / C

[0086] - UV lamp: 7 mW cm -2

[0087] The data shows a stable CO2 signal and a 25 ppm decrease in the O2 signal, corresponding to an induction efficiency of approximately 65%.

[0088] Summary of reference numerals

[0089] 1: First reactor

[0090] 111, 211, 311, 411: (Photo)cathode of the first reactor

[0091] 112, 212, 312, 412: Anion exchange membrane (AEM) of the first reactor

[0092] 113, 213, 313, 413: Photoanode of the first reactor

[0093] 114, 214, 314, 414: Fluid inlet of the (photo)cathode of the first reactor

[0094] 115, 215, 315, 415: Photoanode fluid inlet of the first reactor

[0095] 116, 216: Fluid outlet of the (photo)cathode of the first reactor

[0096] 117, 217: Fluid outlet of the photoanode of the first reactor

[0097] 2: Second reactor

[0098] 121, 221, 321, 421: (Photo)cathode of the second reactor

[0099] 122, 222, 322, 422: Proton exchange membrane (PEM) of the second reactor

[0100] 123, 223, 323, 423: Photoanode of the second reactor

[0101] 124, 224: Fluid inlet of the (photo)cathode of the second reactor

[0102] 125, 225: Photoanode fluid inlet of the second reactor

[0103] 126, 226, 326, 426: Fluid outlet of the (photo)cathode of the second reactor

[0104] 127, 227, 327, 427: Fluid outlets of the photoanodes of the second reactor

[0105] 330, 430: Dividers for the solid agglomerate assemblies of the first and second reactors.

Claims

1. A carbon dioxide capture device, comprising: (a) a first reactor, which comprises an anion exchange membrane disposed between a porous photoanode and a porous photocathode, wherein the photoanode contains or is physically or electrically connected to an oxygen evolution catalyst and / or a carbon dioxide evolution catalyst, and the photocathode contains or is physically or electrically connected to an oxygen reduction catalyst; (b) a second reactor, which comprises a proton exchange membrane disposed between a porous photoanode and a porous photocathode, wherein the photoanode contains or is physically or electrically connected to an oxygen evolution catalyst, and the photocathode contains or is physically or electrically connected to an oxygen reduction catalyst; wherein the porous photocathode of the first reactor has at least fluid inlets capable of transporting carbon dioxide, air, and water, and the porous photoanode of the first reactor has at least fluid inlets capable of transporting water and oxygen, the porous photocathode of the second reactor has at least fluid outlets capable of transporting carbon dioxide and water, and the porous photoanode of the second reactor has at least fluid outlets capable of transporting water and oxygen, wherein the carbon dioxide capture device is configured to transfer the fluid exiting the porous photocathode of the first reactor to the porous photoanode of the second reactor and transfer the fluid exiting the porous photoanode of the first reactor to the porous photocathode of the second reactor.

2. The carbon dioxide capture device according to claim 1, wherein: - the porous photocathode of the first reactor has a fluid inlet and a fluid outlet, both of which are capable of transporting carbon dioxide in air and water, and the porous photoanode of the first reactor has a fluid inlet and a fluid outlet, both of which are capable of transporting water and oxygen; - the porous photocathode of the second reactor has a fluid inlet and a fluid outlet, both of which are capable of transporting carbon dioxide, oxygen, and water, and the porous photoanode of the second reactor has a fluid inlet and a fluid outlet, both of which are capable of transporting water and oxygen, wherein the fluid outlet of the porous photocathode of the first reactor is fluidly connected to the fluid inlet of the porous photoanode of the second reactor, and the fluid outlet of the porous photoanode of the first reactor is fluidly connected to the fluid inlet of the porous photocathode of the second reactor.

3. The carbon dioxide capture device according to claim 1, wherein the first and second reactors are disposed in a solid mass separated by a partition such that the porous photocathode of the first reactor is located opposite the porous photoanode of the second reactor and is separated therefrom by the partition, and the porous photoanode of the first reactor is opposite the porous photocathode of the second reactor and is separated therefrom by the partition, and a single fluid pipeline including the fluid inlet of the porous photocathode of the first reactor and the fluid outlet of the porous photoanode of the second reactor travels along one wall of the solid mass, and another single fluid pipeline including the fluid inlet of the porous photoanode of the first reactor and the fluid outlet of the porous photocathode of the second reactor travels along another wall of the solid mass, the two walls face each other and both are in contact with the partition.

4. The carbon dioxide capture device according to any one of claims 1 to 3, wherein the porous photoanode of the first reactor comprises: BiVO4, TaO x N y , LaTiO2N, BaTaO2N, SrTaO2N, WO3, CuWO4, Fe2O3, ZnFe2O4, and / or TiO2.

5. The carbon dioxide capture device according to claim 4, wherein the porous photoanode of the first reactor further comprises a cocatalyst material based on one or more of the following: Ni, Raney Ni, NiCo, NiFe, NiP, CoP, CoPi, SrCoO3, Ru, Mg, Ag, Au, Fe-OOH, Ni-OOH, IrOx, CoOH, FeOx, Pt, Rh, RhOx, RuOx, and PtOx.

6. The carbon dioxide capture device according to any one of claims 1 to 3, wherein the porous photoanode of the second reactor comprises: BiVO4, TaO x N y , LaTiO2N, BaTaO2N, CuWO4, WO3, and / or TiO2.

7. The carbon dioxide capture device according to claim 6, wherein the porous photoanode of the second reactor further comprises a cocatalyst material based on one or more of the following: Ir, IrOx, Rh, RhOx, Pt, PtOx, Ni, Co, CoOx, NiOx, MnOx, cobalt phosphate, Mg, Ru, Au, Pt3M where M = Ni or Co or Y, PtRu, NiP, CoP, FeP, NiCo, NiMo, and NiW.

8. The carbon dioxide capture device according to any one of claims 1 to 3, wherein the porous photocathode of the first reactor comprises one or more of the following: MoS2, MoSe2, WS2, GaP, CdS, CdSe, ZnSe, CuNbO4, PMPDI, InP, WSe2, ZnFe2O4, CuNbO3, PMPDI, Cu2O, g-C3N4, CIGS, CIGSe, CaFeO2, CuFeO2.

9. The carbon dioxide capture device according to claim 8, wherein the porous photocathode of the first reactor further comprises a cocatalyst material based on one or more of the following: Ni, Raney Ni, LaNiO3, LaMnO3, Ag, Ru, Au, Pt, Pt3M where M = Ni or Co or Y, PtRu, Co, NiP, CoP, FeP, NiCo, NiMo, NiW, Ir, Mg, Ru, Pt, Rh, and RhOx.

10. The carbon dioxide capture device according to any one of claims 1 to 3, wherein the porous photocathode of the second reactor comprises one or more of the following: MoS2, MoSe2, WS2, GaP, CdS, CdSe, ZnSe, CuNbO4, PMPDI, InP, WSe2, ZnFe2O4, CuNbO3, PMPDI, Cu2O, g-C3N4, CIGS, CIGSe, CaFeO2, and CuFeO2.

11. The carbon dioxide capture device according to claim 10, wherein the porous photocathode of the second reactor further comprises a cocatalyst material based on the following: Ru, Au, Pt, Pt3M where M = Ni, Co, Y, PtRu, NiP, CoP, FeP, NiCo, NiMo, and / or NiW.

12. The carbon dioxide capture device according to any one of claims 1 to 3, wherein the porous photoanode of the first reactor and / or the porous photoanode of the second reactor and / or the porous photocathode of the first reactor and / or the porous photocathode of the second reactor comprises a porous substrate, and the porous substrate comprises a material selected from carbon; titanium; tungsten; stainless steel; nickel; and conductive oxides.

13. The carbon dioxide capture device according to claim 12, wherein the porous substrate is in the form of a mesh, felt or foam.

14. The carbon dioxide capture device according to any one of claims 1 to 3, wherein the anion exchange membrane of the first reactor comprises a material selected from the following: a material containing a quaternary ammonium group; a low density polyurethane having a quaternary ammonium group; a material containing an imidazolium or polybenzimidazole group; and a tri- or di-amine crosslinked quaternized polysulfone.

15. The carbon dioxide capture device according to claim 14, wherein the anion exchange membrane of the first reactor comprises a material having a vinylbenzyl chloride and an imidazolium group.

16. The carbon dioxide capture device according to any one of claims 1 - 3, wherein the proton exchange membrane of the second reactor comprises a material selected from the following: perfluorocarbon sulfonic acid polymers; polysulfonic acid polymers; polybenzimidazoles; polyacrylic acids; and hydrocarbon membrane materials.

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