Photocatalyst for capturing and converting low concentrations of carbon dioxide in the atmosphere

Abstract

A photocatalyst for capturing and converting low concentrations of carbon dioxide in the atmosphere, and a method for capturing and photoconverting carbon dioxide in the atmosphere using the same are disclosed. The photocatalyst for capturing and converting carbon dioxide may include a bismuth oxyhalide supported with one or more metals and having oxygen vacancies.

Description

Technical Field

[0001] The present invention relates to a photocatalyst for carbon dioxide collection and conversion capable of directly collecting low-concentration carbon dioxide under actual atmospheric conditions and converting it into high-value-added substances, and a method for collecting and photocatalytically converting carbon dioxide in the atmosphere using the same.

Background Art

[0002] The emission amount of carbon dioxide has been continuously increasing, and it is predicted that the global temperature will rise by about 2.1 °C by 2100. To solve this problem, research on the development of technologies for carbon dioxide reduction has been actively carried out. However, it is difficult to rapidly reduce the emission amount of carbon dioxide in a short period of time in reality. As a solution for sustainable growth, currently, carbon capture technology (CCS) or CCU technology has been adopted as a practical solution for carbon dioxide reduction, and the demonstration of direct air capture (Direct Air CO2 Capture: DAC) technology is underway.

[0003] However, such technologies mainly use metal-organic frameworks (MOFs), zeolites, etc. as capture agents, but the consumption of water resources for the regeneration of the captured substances and the consumption of additional energy such as thermal energy are raised as problems. In addition, due to the competitive adsorption method, it is greatly affected by oxygen and moisture contained in actual air, and since MOFs have reduced durability at high temperatures, it becomes a problem when applying a reaction for continuously removing carbon dioxide in actual air.

Summary of the Invention

Problems to be Solved by the Invention

[0004] One object of the present invention is to provide a photocatalyst for carbon dioxide collection and conversion that can selectively collect low-concentration carbon dioxide in the atmosphere under conditions containing oxygen and moisture and convert it into high-value-added compounds using sunlight. Another object of the present invention is to provide a method for capturing and photoconverting carbon dioxide in the atmosphere using the photocatalyst. [Means for solving the problem]

[0005] In one aspect, the present invention provides a photocatalyst for capturing and converting carbon dioxide, comprising bismuth oxyhalide having oxygen vacancies and supported by one or more metals. In one embodiment, the metal may be selected from Cu, Fe, Co, Ni, Mn, Ru, Pt, Au, and Ag. In one embodiment, the metal may be present in an amount of 0.01 to 2 wt% relative to the total weight of the catalyst. In one embodiment, the metal comprises Cu and Fe, and the Cu may be present in an amount of 0.01 to 0.5 wt% and the Fe in an amount of 0.3 to 1 wt% relative to the total weight of the catalyst. In one embodiment, the photocatalyst can selectively capture carbon dioxide at concentrations of 1000 ppm or less in the atmosphere under dark conditions, and can convert the captured carbon dioxide into CO or CH4 upon irradiation with light. In other aspects, the present invention provides a method for capturing and photoconverting carbon dioxide from the atmosphere, comprising a first step of selectively capturing carbon dioxide from the atmosphere using the photocatalyst, and a second step of irradiating the catalyst on which the carbon dioxide has been captured with light to reduce it to a photoconversion product. In one embodiment, the first step may be performed under dark conditions. In one embodiment, the photoconversion product may include CO or CH4. [Effects of the Invention]

[0006] The photocatalyst according to the present invention has improved carbon dioxide adsorption and catalytic activity due to the oxygen vacancy activity of bismuth oxyhalide, and the photoconversion rate of the collected carbon dioxide can be further improved by the structure on which one or more metals are supported. Furthermore, by using the photocatalyst of the present invention, low concentrations (approximately 450 ppm) of carbon dioxide in the atmosphere can be selectively adsorbed under dark conditions (nighttime) where oxygen and moisture are present, and the adsorbed carbon dioxide can be photoconverted under conditions with light (daytime) to reduce it to high value-added substances. [Brief explanation of the drawing]

[0007] [Figure 1] This is a drawing showing a photocatalyst for carbon dioxide capture and conversion according to an embodiment of the present invention. [Figure 2] This is a schematic diagram illustrating a method for capturing and photoconverting carbon dioxide from the atmosphere according to an embodiment of the present invention. [Figure 3] This is a drawing showing experimental results from an experimental example of the present invention. [Figure 4] This is a drawing showing experimental results from an experimental example of the present invention. [Figure 5] This is a drawing showing experimental results from an experimental example of the present invention. [Figure 6] This is a drawing showing experimental results from an experimental example of the present invention. [Figure 7] This is a drawing showing experimental results from an experimental example of the present invention. [Figure 8] This is a drawing showing experimental results from an experimental example of the present invention. [Figure 9] This is a drawing showing experimental results from an experimental example of the present invention. [Figure 10] This is a drawing showing experimental results from an experimental example of the present invention. [Figure 11] This is a drawing showing experimental results from an experimental example of the present invention. [Figure 12] This is a drawing showing experimental results from an experimental example of the present invention. [Figure 13] This is a drawing showing experimental results from an experimental example of the present invention. [Modes for carrying out the invention]

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention can be subjected to various modifications and can have various forms. Specific embodiments are illustrated in the drawings and will be described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, and it should be understood that it includes all modifications, equivalents, or alternatives included in the spirit and technical scope of the present invention. When explaining each drawing, similar reference numerals are used for similar components. In the accompanying drawings, the dimensions of the structures are shown enlarged for the clarity of the present invention.

[0009] The terms used in this application are only used to explain specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, terms such as "comprising" or "having" are intended to specify the presence of features, numbers, steps, operations, components, or combinations thereof described in the specification, and do not pre-exclude the presence or addition possibility of one or more other features, numbers, steps, operations, components, or combinations thereof.

[0010] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention pertains. Terms defined as in commonly used dictionaries should be interpreted to have a meaning consistent with the meaning in the context of the related art, and should not be interpreted in an ideal or overly formal sense unless clearly defined in this application.

[0011] FIG. 1 is a drawing showing a photocatalyst for carbon dioxide collection and conversion according to an embodiment of the present invention.

[0012] Referring to FIG. 1, the photocatalyst for carbon dioxide collection and conversion according to an embodiment of the present invention may include bismuth oxyhalide having one or more metals supported thereon and oxygen vacancies.

[0013] The bismuth oxyhalide of the present invention can be represented by BiOX (X = Cl, Br, I). Further, the bismuth oxyhalide of the present invention may have oxygen vacancies. The bismuth oxyhalide activated by oxygen vacancies can adsorb carbon dioxide in the atmosphere about three times or more than that of the bismuth oxyhalide without vacancies.

[0014] On the other hand, the bismuth oxyhalide having oxygen vacancies of the present invention may support one or more metals. By supporting the metal, the carbon dioxide collection performance of the catalyst is improved, and the photocatalytic conversion performance can be improved about 2.5 times or more compared to the bismuth oxyhalide activated by oxygen vacancies.

[0015] In one embodiment, the metal can be selected from Cu, Fe, Co, Ni, Mn, Ru, Pt, Au, and Ag, but is not particularly limited. Further, in order to improve the selective collection and photocatalytic conversion performance of carbon dioxide at low concentrations (about 1000 ppm or less) in the atmosphere, the metal can be contained at 0.01 to 2 wt% based on the total weight of the catalyst, but is not limited thereto, and can be contained at an appropriate content according to each metal.

[0016] Preferably, the photocatalyst may contain a bimetal. At this time, it may contain two metals selected from the above-mentioned metals, and most preferably, it may contain Cu and Fe. Further, in order to obtain optimal carbon dioxide collection and photocatalytic conversion performance, the Cu is contained at 0.01 to 0.5 wt% and the Fe may be contained at 0.3 to 1 wt% based on the total weight of the catalyst.

[0017] The photocatalyst of the present invention can selectively collect carbon dioxide of 1000 ppm or less in the atmosphere under dark conditions and can convert the carbon dioxide collected during light irradiation into CO or CH4. More specifically, the photocatalyst of the present invention can selectively adsorb low-concentration (approximately 450 ppm) carbon dioxide in the atmosphere under dark conditions (nighttime) where oxygen and moisture are present, and then convert the adsorbed carbon dioxide into high-value-added substances, CO or CH4, under conditions where light is present (daytime).

[0018] Figure 2 is a schematic diagram showing a method for capturing and photoconverting carbon dioxide from the atmosphere according to an embodiment of the present invention.

[0019] Referring to Figure 2, the method for capturing and photoconverting carbon dioxide from the atmosphere according to an embodiment of the present invention may include a first step of selectively capturing carbon dioxide from the atmosphere using the photocatalyst of the present invention, and a second step of irradiating the catalyst on which the carbon dioxide has been captured with light to reduce it to a photoconversion product.

[0020] The first step is to selectively capture low concentrations of carbon dioxide in the atmosphere using the photocatalyst of the present invention. The first step can be carried out under dark conditions. Using the photocatalyst of the present invention, carbon dioxide can be effectively adsorbed even in a typical atmospheric environment that contains oxygen and moisture and low concentrations (about 450 ppm) of carbon dioxide.

[0021] The second step involves irradiating the catalyst containing the collected carbon dioxide with light to reduce it to a photoconversion product. Here, the light irradiation can be sunlight, or light of the same or similar wavelength as sunlight. For example, AM 1.5 (100 mW cm²). -2 Light may be irradiated under the following conditions. On the other hand, by irradiation with light, carbon dioxide can be reduced to a photoconversion product containing CO or CH4.

[0022] According to the present invention, low-concentration (approximately 450 ppm) carbon dioxide in the atmosphere can be selectively adsorbed under dark conditions (nighttime) where oxygen and moisture are present, and the adsorbed carbon dioxide can be photoconverted under conditions with light (daytime) to reduce it to high-value-added substances.

[0023] The following describes embodiments of the present invention in detail. However, the embodiments described below represent only some embodiments of the present invention, and the scope of the present invention is not limited to these embodiments.

[0024] [Example 1: Production of bismuth oxyhalide (Pure BiOX (X=Cl, Br, I))] Dissolve Bi(NO3)3·5H2O (5 mmol) in 50 mL of distilled water (DI water) by sonication for at least 10 minutes. Add 5 mmol each of NaX(X=Cl,Br,I) and stir for 30 minutes. Place the completely dissolved solution into a 100 mL PTFE liner and perform hydrothermal synthesis at 160°C for 16 hours. After the reaction is complete and the solution has cooled to room temperature, wash it several times with water and ethanol. After obtaining the powder using a centrifuge, dry it in an oven at 60°C for at least 12 hours.

[0025] [Example 2: Production of bismuth oxyhalide activated by oxygen vacancies (Ov BiOX)] Add Bi(NO3)3·5H2O (5 mmol) to 50 mL of ethylene glycol solution and sonicate completely for at least 10 minutes. Add 5 mmol of NaX (X=Cl,Br,I) and stir for 30 minutes. Add 0-2 mL of 1 M HX (X=Cl,Br,I) and stir for 5 minutes. Place the completely dissolved solution into a 100 mL PTFE liner and perform hydrothermal synthesis at 160°C for 16 hours. After the reaction is complete and the mixture has cooled to room temperature, wash several times with water and ethanol. After obtaining the powder by centrifugation, dry it in a 60°C oven for at least 12 hours. To remove trace amounts of organic matter from the dried powder, heat treat it at 300°C (10°C / min) for 1 hour under an Ar atmosphere.

[0026] [Example 3: Production of bismuth oxyhalide activated by metal-bonded oxygen vacancies (M / Ov BiOX)] To bond a metal to the Ov BiOX catalyst prepared according to Example 2, 400 mg of Ov BiOX was placed in a PTFE beaker and 60 mL of distilled water was added. After adding the metal precursor at a concentration of 0.01-3 wt%, the mixture was immersed in a preheated 90°C water bath and stirred for 1 hour and 30 minutes. After the reaction was complete and the mixture cooled to room temperature, it was washed with water, centrifuged, and dried in a 60°C oven for at least 12 hours.

[0027] [Example 4: Production of bismuth oxyhalide activated by oxygen vacancies formed by the bonding of two metals (M1M2 / Ov BiOX)] To bond other metals to the M / Ov BiOX catalyst prepared according to Example 3, 400 mg of M / Ov BiOX was placed in a PTFE beaker and 60 mL of distilled water was added. After adding the metal precursor at a concentration of 0.01-3 wt%, the mixture was immersed in a preheated 90°C water bath and stirred for 1 hour and 30 minutes. After the reaction was complete and the mixture cooled to room temperature, it was washed with water, centrifuged, and dried in a 60°C oven for at least 12 hours.

[0028] [Experimental Example 1: Catalyst Characterization] To analyze the crystal structure of the catalysts according to Examples 1-4, the Pure BiOCl (Example 1), Ov BiOCl (Example 2), and CuFe / Ov BiOCl (Example 4) powders were measured using an EMPUREAN instrument from PANalytical, irradiated with Cu-Kα radiation at a wavelength of 1.5406 Å (40 kV, 30 mA).

[0029] Referring to Figure 4, which shows the results, it can be seen that there is good agreement with BiOCl (JCPDS 06-0249). The diffraction peak of Ov-BiOCl with activated oxygen vacancies showed a tendency to be lower in intensity and broader in peak width compared to the pure BiOCl catalyst. Furthermore, CuFe / Ov BiOCl, each supported with CuFe ions, did not show significant changes in XRD.

[0030] Meanwhile, to measure the composition and components of the catalyst surface, a ThermoFisher (NEXSA) instrument was irradiated with Al-Kα (1486.6 eV) and measured in powder form: Pure BiOCl (Example 1), Ov BiOCl (Example 2), and CuFe / Ov BiOCl (Example 4). The surface elemental composition of the prepared samples was analyzed to show the composition of Bi, Cl, and O elements, and the elemental composition of Cu and Fe was also confirmed in the case of CuFe / Ov BiOCl.

[0031] As shown in Figure 5, which illustrates the results, first, comparing the Bi 4f peaks, the peaks at 159.2 eV and 164.5 eV are Bi 4f 7 / 2 and Bi 4f 5 / 2 Two peaks appeared, and Ov BiOCl with activated oxygen vacancies shifted by only 0.2 eV at lower binding energies (159 and 164.3 eV). This is due to the oxygen vacancy in Bi. (3-x)+ This phenomenon is caused by formation. The Cl 2p spectrum also shows Cl 2p 3 / 2 and Cl 2p 1 / 2 Two peaks belonging to this group were identified. The new peak in Ov BiOCl, where the O 1s peak is observed at a higher bond energy, may be due to oxygen coordination such as OH or adsorbed oxygen. This also suggests the presence of oxygen vacancies. It was revealed that the contribution of Bi-O decreases in BiOCl where Ov is formed by the removal of the oxygen atom bonded to the Bi atom. In Figure 5(d), Cu and Fe ions are well supported in CuFe / Ov BiOCl, and the elements are identified.

[0032] Next, to observe the change in catalyst color after surface modification and to identify the catalyst's light absorption region, measurements were taken using Shimadzu analytical instruments. Using BaSO4 (Barium sulfate) as a baseline, the light absorption spectrum in the catalyst powder form was measured in the wavelength range of 200 nm to 900 nm.

[0033] As a result, as can be seen from the catalyst color in Figure 6, the catalyst color changed to a dark brown (Ov BiOCl) upon activation of oxygen vacancies. Furthermore, as seen in the DRS, the absorption in the visible and infrared wavelength ranges of the catalyst with activated oxygen vacancies was significantly increased compared to conventional BiOCl. The catalyst supported with CuFe ions did not show significant differences in catalyst color and DRS compared to Ov BiOCl.

[0034] On the other hand, for image observation of the ultrafine region of the catalysts according to Examples 1-4, as well as for component and structural analysis, CuFe / Ov BiOCl sample powders were measured using a field emission transmission electron microscope (FE-TEM) (200kV).

[0035] As a result, the (001) and (101) lattices of BiOCl were confirmed by TEM analysis, similar to the crystalline phase confirmed by XRD (Figure 7(a)). Furthermore, metal cluster-like deposits were observed on the surface in Figures 7(b) and (c). The presence or absence of Bi, O, Cl, Cu, and Fe elements was confirmed by EDS analysis, and the BiOCl catalyst was confirmed by TEM, revealing that Cu and Fe were well supported.

[0036] [Experimental Example 2: Adsorption and Conversion Experiment of Carbon Dioxide in the Atmosphere] To evaluate the adsorption and conversion performance of atmospheric carbon dioxide, actual atmospheric conditions of approximately 0.05% carbon dioxide (CO2) / air atmosphere (Air Balance) were used. 150 mg of the catalyst from Example 4 was placed in a 3 cm wide area. 2 The sample was placed in a sample holder and positioned at the bottom of a stainless steel reactor containing approximately 120 mL of gas. For surface pretreatment (removal of carbon and organic matter), air was flowed through the mixture at 200°C for 12 hours. The concentrations of carbon dioxide and air were adjusted by controlling the flow rates using flow controllers (MFCs), and the mixture was passed through an impinger containing water to maintain a humidity of ±45%. This mixed gas was pre-packaged in a sampling gas bag, and after the pretreatment was complete, the reactor was evacuated and the pre-prepared gas bag was used to fill the reactor.

[0037] Carbon dioxide was collected for 2 hours, and the change in the collected concentration was observed. (Light source: sunlight, AM 1.5, 100mW cm) -2 The reactor was irradiated with ) and the gas inside was sampled for a predetermined time to confirm the substances and amounts produced. The amount of decomposition and production of the gas was confirmed by quantitative analysis of carbon monoxide and carbon dioxide using GC-FID(YL) (see Figure 3).

[0038] [Experimental Example 3: Results of experiments on the adsorption and conversion of carbon dioxide in the atmosphere] Comparison of atmospheric carbon dioxide capture and conversion using Pure BiOCl and Ov BiOCl catalysts. Figure 8 shows the capture and conversion of atmospheric carbon dioxide using Pure BiOCl and Ov BiOCl catalysts activated with oxygen vacancies. (a) shows the results of capture under approximately 0.05% carbon dioxide conditions in an oxygen-containing air atmosphere similar to atmospheric carbon dioxide conditions, and (b) and (c) show the concentrations of carbon monoxide and methane, which are products converted by sunlight using the captured carbon dioxide. The results showed that the carbon dioxide capture efficiency of the catalyst activated by oxygen vacancies was 150 ppmv, approximately three times higher than that of Pure BiOCl. This confirmed that carbon dioxide was selectively and relatively better adsorbed by the oxygen vacancy-activated portion. Furthermore, the photoconversion product of the captured carbon dioxide showed that the Ov BiOCl catalyst produced more than three times more carbon dioxide than Pure BiOCl.

[0039] Evaluation of the collection performance of Ov BiOCl under atmospheric carbon dioxide concentration and humidity conditions. Figure 9 shows the results of evaluating the carbon dioxide capture performance of the Ov BiOCl catalyst at atmospheric carbon dioxide concentrations (0.05-1%). The results showed that at 0.1% (1000 ppmv), approximately 250 ppmv was captured, and the photoconversion products were CO and CH4 at 15 ppmv and 2 ppmv, respectively. Furthermore, at a carbon dioxide concentration of 1% (10000 ppmv), approximately 1200 ppmv was captured, and the photoconversion products were CO and CH4 at 18 ppmv and 3 ppmv, respectively. We compared the amount of carbon dioxide collected and the resulting photoconversion products based on the concentration of carbon dioxide in the atmosphere. The results showed a tendency for collection and photoconversion performance to increase as the carbon dioxide concentration increased. Next, we evaluated the carbon dioxide capture and conversion performance under different humidity levels. The results showed that there was no significant difference in carbon dioxide capture levels due to humidity. It appears that selective carbon dioxide adsorption is unaffected by competition with water. However, in terms of photoconversion performance, the highest product concentrations of CO and CH4 were observed at RH 85%, which is attributed to the difference caused by H generated on the surface as water dissociates.

[0040] Comparison of atmospheric carbon dioxide capture and conversion using M / Ov BiOCl Figures 10(a) to (c) show the results of comparing the carbon dioxide capture and conversion performance of catalysts supported with Cu, Fe, and Co, respectively, on Ov BiOCl catalysts. The performance was compared by supporting various metals according to their content (0.01 to 2 wt%), and the differences in carbon dioxide capture and photoconversion performance were confirmed. By supporting a metal, carbon dioxide capture was increased by approximately 30-50 ppmv compared to conventional Pure BiOCl and Ov BiOCl, and the photoconversion performance was improved by more than four times compared to Pure BiOCl. The carbon dioxide capture and conversion performance was optimized with 0.05 wt% Cu, 1 wt% Fe, and 0.3 wt% Co.

[0041] Comparison of atmospheric carbon dioxide capture and conversion using M1M2 / Ov BiOCl Figure 11(a) shows the results of a comparison of the carbon dioxide capture and conversion performance of bimetallic photocatalysts M1M2 / Ov BiOCl (M1M2 = CuCo, CuNi, CuFe). The results showed that the CuFe-supported photocatalyst exhibited the best carbon dioxide capture and conversion performance. Compared to Pure BiOCl and Ov BiOCl, the capture performance increased by approximately 160 ppmv and 100 ppmv, respectively, and the conversion performance improved by approximately 5 times and more than 2.5 times, respectively. Thus, it was confirmed that performance is improved when Cu+Co, Cu+Ni, or Cu+Fe are supported in combination with conventional catalysts. Figure 11(b) shows the results of evaluating the carbon dioxide capture and conversion performance by fixing the 0.05 wt% Cu content, which yielded the best performance, and adding Fe at different content levels in order to optimize the final selected Cu and Fe content. The best performance was observed when the Cu content was 0.05 wt% and the Fe content was 0.3 wt%.

[0042] Optimized catalyst's performance in capturing and converting atmospheric carbon dioxide. Figure 12 shows the carbon dioxide capture and conversion performance of the optimized catalysts. Referring to Figure 12, Fe / Ov BiOCl containing 1 wt% Fe showed the highest carbon dioxide capture performance, followed by CuFe / Ov BiOCl containing 0.05 wt% Cu and 0.3 wt% Fe, which also showed high carbon dioxide capture performance. On the other hand, the photoconversion performance of the bimetallic catalyst (CuFe / Ov BiOCl) was significantly higher than that of Fe / Ov BiOCl and Cu / Ov BiOCl.

[0043] Comparison of atmospheric carbon dioxide capture and conversion using Pure BiOX and Ov BiOX (X=Cl, Br, I). Figure 13 shows the carbon dioxide capture and conversion performance of catalysts with varying halogen elements. Referring to Figure 13, catalysts containing Cl, Br, and I all demonstrated carbon dioxide capture and conversion performance. Although the above has been described with reference to preferred embodiments of the present invention, a person with ordinary skill in the art should understand that the present invention can be modified and altered in various ways without departing from the spirit and scope of the invention as described in the claims.

Claims

1. A photocatalyst for capturing and converting carbon dioxide, comprising a bismuth oxyhalide supported by one or more metals and having oxygen vacancies.

2. The photocatalyst for capturing and converting carbon dioxide according to claim 1, wherein the metal is selected from Cu, Fe, Co, Ni, Mn, Ru, Pt, Au, and Ag.

3. The photocatalyst for capturing and converting carbon dioxide according to claim 1, wherein the metal is contained in an amount of 0.01 to 2 wt% relative to the total weight of the catalyst.

4. The photocatalyst for capturing and converting carbon dioxide according to claim 1, wherein the metal comprises Cu and Fe.

5. The photocatalyst for capturing and converting carbon dioxide according to claim 4, wherein Cu is contained in an amount of 0.01 to 0.5 wt% and Fe is contained in an amount of 0.3 to 1 wt% based on the total weight of the catalyst.

6. The photocatalyst for capturing and converting carbon dioxide according to claim 1 is characterized in that the photocatalyst selectively captures carbon dioxide in the atmosphere at concentrations of 1000 ppm or less under dark conditions.

7. The aforementioned photocatalyst converts carbon dioxide collected during light irradiation into CO or CH4. ４ The photocatalyst for capturing and converting carbon dioxide according to claim 6, characterized by converting to

8. A first step of selectively capturing carbon dioxide from the atmosphere using a photocatalyst according to any one of claims 1 to 7; and The second step involves irradiating the catalyst containing the collected carbon dioxide with light to reduce it to a photoconversion product; A method for capturing and photoconverting carbon dioxide from the atmosphere, including [a specific component].

9. The method for capturing and photoconverting atmospheric carbon dioxide according to claim 8, characterized in that the first step is carried out under dark conditions.

10. The aforementioned photoconversion product is CO or CH ４ A method for capturing and photoconverting carbon dioxide from the atmosphere according to claim 8, comprising:

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