Atomically dispersed catalyst and forming method therefor

Abstract

An atomically dispersed catalyst and a forming method therefor are provided. The atomically dispersed catalyst comprises a metal oxide support and metal atoms dispersed in the metal oxide support. The atomically dispersed catalyst forming method comprises the steps of: forming a metal oxide dispersion solution and a metal precursor solution; irradiating the metal oxide dispersion solution with light; and adding the metal precursor solution to the metal oxide dispersion solution irradiated with light.

Description

Atomic dispersion catalyst and method for forming the same

[0001] The present invention relates to an atomic dispersion catalyst and a method for forming the same.

[0002] Catalysts in which metal atoms are attached to a support in an atomic state have been extensively studied because they can increase atom utilization efficiency. However, conventional synthetic methods are often only applicable to specific metal atoms and support types, and the synthesis process often requires high thermal energy. Furthermore, the interaction between the metal atoms and the support is often simple and ends in physical adsorption, resulting in low catalytic performance.

[0003] The present invention provides an atomic dispersion catalyst having excellent performance.

[0004] The present invention provides a method for forming the above-described atomic dispersion catalyst.

[0005] Other objects of the present invention will become apparent from the following detailed description and the accompanying drawings.

[0006] An atomic dispersion catalyst according to embodiments of the present invention comprises a metal oxide support and metal atoms dispersed in the metal oxide support.

[0007]

[0008] A method for forming an atomic dispersion catalyst according to embodiments of the present invention includes a step of forming a metal oxide dispersion and a metal precursor solution, a step of irradiating light to the metal oxide dispersion, and a step of adding the metal precursor solution to the light-irradiated metal oxide dispersion.

[0009] The atomically dispersed catalyst according to embodiments of the present invention can exhibit excellent performance. For example, the metal atoms of the atomically dispersed catalyst can be uniformly distributed on a metal oxide support, thereby increasing the utilization efficiency of the metal atoms and resulting in high catalytic activity. Furthermore, the metal atoms are attached to the metal oxide support through strong and specific chemical interactions, and because they possess a large number of electrons, they can exhibit excellent catalytic performance in reduction reactions (e.g., hydrogen evolution reactions). Furthermore, the atomically dispersed catalyst can be readily formed through a simple process without requiring high thermal energy.

[0010] Figure 1 shows the surface Ti due to the movement of oxygen defects upon light irradiation on TiO2. 3+ The results of density function simulation of the generation and Pt loading process are shown.

[0011] Figure 2 shows the results of density functional simulations regarding the stable structure of Pt supported in an atomic state on TiO2.

[0012] Figure 3 shows the EPR spectrum for investigating Pt loading on photochemically generated defects in TiO2.

[0013] Figure 4 shows the EPR spectrum for investigating the air regeneration process of photo-irradiated TiO2.

[0014] Figure 5 shows EXAFS spectra of Pt-DSA / TiO2, Pt-NP / TiO2, PtO2, and Pt foil.

[0015] Figure 6 shows the XPS spectrum of Pt-DSA / TiO2.

[0016] Figure 7 shows the XANES spectrum of Pt-DSA / TiO2.

[0017] Figure 8 shows the EPR spectrum for investigating Pt loading on photochemically generated defects in ZnO.

[0018] Figure 9 shows the EPR spectrum for investigating Pt loading on photochemically generated defects in CeO2.

[0019] Figure 10 shows the hydrogen evolution reaction activity of Pt-DSA / TiO2 photocatalyst at different amounts of Pt loading.

[0020] Figure 11 shows the hydrogen evolution reaction activity of Pt-DSA / TiO2 photocatalyst and Pt-NP / TiO2 photocatalyst at different amounts of Pt loading.

[0021] Figure 12 shows the conversion frequency of the hydrogen evolution reaction of the catalyst of Figure 11.

[0022] Figure 13 shows the results of measuring the hydrogen generation reaction four times continuously at one-hour intervals using a Pt-DSA / TiO2 photocatalyst and a Pt-SA / hydrogenated TiO2 photocatalyst.

[0023] Figure 14 shows the initial yields of hydrogen generation through PET photomodification using Pt-DSA / TiO2, Pt-SA / hydrogenated TiO2, and Pt-NP / TiO2.

[0024] Figure 15 shows the results of scale-up and long-term cycling PET photomodification measurements of Pt-DSA / TiO2.

[0025] Figure 16 shows the conversion of PET to hydrogen in the photomodification of Pt-DSA / TiO2 of Figure 14.

[0026] Figure 17 schematically shows PET photomodification using Pt-DSA / TiO2.

[0027] Figure 18 shows the PET photomodification reaction using Pt-DSA / TiO2 before and after 40 hours. 1 H NMR spectrum is shown.

[0028] Hereinafter, the present invention will be described in detail through examples. The objects, features, and advantages of the present invention will be readily understood through the following examples. The present invention is not limited to the examples described herein and may be embodied in other forms. The examples introduced herein are provided so that the disclosed content can be thorough and complete, and so that the spirit of the present invention can be sufficiently conveyed to those skilled in the art to which the present invention pertains. Therefore, the present invention should not be limited by the following examples. In the examples of the present invention, TiO2, ZnO, CeO2 are described as metal oxide supports, and Pt, Ir, Cu are described as metal atoms, but the technical spirit of the present invention is not limited thereto and can be expanded and applied to other metal oxides and metal atoms.

[0029]

[0030] An atomic dispersion catalyst according to embodiments of the present invention comprises a metal oxide support and metal atoms dispersed in the metal oxide support.

[0031] The metal oxide support may include at least one of TiO2, ZnO, and CeO2. The metal atom may include at least one of Pt, Ir, and Cu.

[0032] The above metal atoms can be dispersed on the surface of the metal oxide support.

[0033] The above-described atomic dispersion catalyst can be formed by forming a metal oxide dispersion and a metal precursor solution, irradiating the metal oxide dispersion with light, and adding the metal precursor solution to the light-irradiated metal oxide dispersion. The light can include ultraviolet-visible (UV-Vis) light. The light irradiation can cause oxygen defects to form on the surface of the metal oxide. The light irradiation can cause oxygen defects within the metal oxide to move to the surface.

[0034]

[0035] A method for forming an atomic dispersion catalyst according to embodiments of the present invention includes a step of forming a metal oxide dispersion and a metal precursor solution, a step of irradiating light to the metal oxide dispersion, and a step of adding the metal precursor solution to the light-irradiated metal oxide dispersion.

[0036] The metal oxide dispersion may be formed by placing a metal oxide in an organic aqueous solution and then ultrasonicating the metal oxide. The metal oxide may include at least one of TiO2, ZnO, and CeO2, and the organic aqueous solution may include a methanol aqueous solution or an ethanol aqueous solution.

[0037] The above metal precursor solution can be formed by diluting a metal precursor with water. The metal precursor can include at least one of H2PtCl6, H2IrCl6, and CuCl2.

[0038] The light may include ultraviolet-visible (UV-Vis) light. By irradiating the light, oxygen defects may be formed on the surface of the metal oxide. By irradiating the light, oxygen defects within the metal oxide may move to the surface.

[0039]

[0040] [Examples and Comparative Examples]

[0041]

[0042] [Formation example of Pt-DSA / TiO2]

[0043] A TiO2 dispersion was prepared by adding 50 mg of anatase TiO2 to 10 mL of a 20% aqueous methanol solution in a 20 mL gas-tight vial and sonicating for 10 minutes. A 1 mL Pt precursor solution was prepared by diluting H2PtCl6 (50, 37.5, 25, and 12.5 μL for Pt-DSA 0.7, 0.6, 0.5, and 0.25 wt% / TiO2, respectively) with H2O. The TiO2 dispersion and the Pt precursor solution were purged with Ar gas for 10 minutes. The TiO2 dispersion was vigorously stirred and illuminated with a xenon lamp light source at 100 mW / cm2. 2 Irradiate with UV-Vis light of high intensity for 20 minutes. After the TiO2 dispersion turns blue, 0.5 ml of Pt precursor solution is injected into the TiO2 dispersion while stirring vigorously. After stirring for 10 minutes, the reaction solution is centrifuged and washed with water and ethanol. The product is dried overnight in an electric oven at 50°C. This results in the formation of Pt-DSA (dynamically stabilized atomic) / TiO2.

[0044]

[0045] [Formation example of Ir-DSA / TiO2]

[0046] 1 mL of Ir precursor solution is prepared by adding 62.2 mg of H2IrCl to H2O. Ir-DSA / TiO2 can be formed in the same manner as Pt-DSA / TiO2 except that the Ir precursor solution is used.

[0047]

[0048] [Formation example of Cu-DSA / TiO2]

[0049] Add 5.4 mg of CuCl2 to H2O to prepare 1 ml of Cu precursor solution. Cu-DSA / TiO2 can be formed in the same manner as Pt-DSA / TiO2 except that a Cu precursor solution is used.

[0050]

[0051] [Formation example of Pt-DSA / ZnO]

[0052] Pt-DSA / ZnO can be formed in the same manner as Pt-DSA / TiO2 except that a ZnO dispersion is used. The ZnO dispersion is irradiated with UV-Vis light for 30 minutes.

[0053]

[0054] [Formation example of Ir-DSA / ZnO]

[0055] Ir-DSA / ZnO can be formed in the same manner as Ir-DSA / TiO2 except that a ZnO dispersion is used. The ZnO dispersion is irradiated with UV-Vis light for 30 minutes.

[0056]

[0057] [Formation example of Cu-DSA / ZnO]

[0058] Cu-DSA / ZnO can be formed in the same manner as Cu-DSA / TiO2 except that a ZnO dispersion is used. The ZnO dispersion is irradiated with UV-Vis light for 30 minutes.

[0059]

[0060] [Formation example of Pt-DSA / CeO2]

[0061] Pt-DSA / CeO2 can be formed in the same manner as Pt-DSA / TiO2 except that a CeO2 dispersion is used. The CeO2 dispersion is irradiated with UV-Vis light for 30 minutes.

[0062]

[0063] [Formation example of Ir-DSA / CeO2]

[0064] Ir-DSA / CeO2 can be formed in the same manner as Ir-DSA / TiO2, except that a CeO2 dispersion is used. The CeO2 dispersion is irradiated with UV-Vis light for 30 minutes.

[0065]

[0066] [Formation example of Cu-DSA / CeO2]

[0067] Cu-DSA / CeO2 can be formed in the same manner as Cu-DSA / TiO2 except that a CeO2 dispersion is used. The CeO2 dispersion is irradiated with UV-Vis light for 30 minutes.

[0068]

[0069] [Formation example of Pt-SA / hydrogenated TiO2]

[0070] Anatase TiO2 is reduced in a 10% H2 / Ar atmosphere at 500°C for 1 hour. 250 mg of hydrogenated TiO is dispersed in 10 mL of H2O in a 20-mL vial by sonication for 10 minutes to form a TiO2 dispersion. 650 μl of H2PtCl is diluted with H2O to form 1 mL of a Pt precursor aqueous solution. 0.5 mL of the Pt precursor solution is injected into the TiO2 dispersion while vigorously stirring. After stirring for 10 minutes, the reaction solution is centrifuged and washed with water and ethanol. The product is dried overnight in an electric oven at 50°C. This results in the formation of Pt-SA / hydrogenated TiO2.

[0071]

[0072] [Formation example of Pt-SA / TiO2]

[0073] 250 mg of anatase TiO2 is added to 10 ml of H2O in a 20 ml airtight vial and sonicated for 10 minutes to prepare a TiO2 dispersion. A Pt precursor solution is prepared in the same manner as in the formation example of Pt-DSA / TiO2. The Pt precursor solution is purged with Ar gas for 10 minutes. 0.5 ml of the Pt precursor solution is injected into the TiO2 dispersion while vigorously stirring the TiO2 dispersion. After stirring for 20 minutes, the reaction solution is centrifuged and washed with water and ethanol. The product is dried overnight in an electric oven at 50°C. Thus, Pt-SA / TiO2 is formed.

[0074]

[0075] [Formation example of Pt-NP / TiO2]

[0076] Prepare a Pt precursor solution using H2PtCl6 (17.5, 15, 12.5, and 6.25 μL for Pt-NP 0.7, 0.6, 0.5, and 0.25 wt% / TiO2, respectively). Add 0.5 mL of Pt precursor solution to 10 mL of 20% methanol aqueous solution in a 20 mL airtight vial. The solution is purged with Ar gas for 10 min and stirred vigorously at 100 mW / cm 2 Irradiate with UV-Vis light of high intensity for 1 hour. Centrifuge the reaction solution, and dissolve the precipitate in 2 ml of H2O. Mix the Pt-NP (nanoparticle) solution with 8 ml of an aqueous TiO2 dispersion containing 50 mg of TiO2. After stirring for 20 minutes, centrifuge the reaction solution and wash with water and ethanol. Dry the product overnight at 50°C in an electric oven.

[0077]

[0078] Figure 1 shows the surface Ti due to the movement of oxygen defects upon light irradiation on TiO2. 3+ The density functional simulation results for the formation and Pt loading process are shown in Fig. 2, and the density functional simulation results for the stable structure of Pt loaded on TiO2 in an atomic state are shown. Fig. 1 shows the thermodynamics of the movement of bulk oxygen defects (Vo) in TiO2 to the surface and the Pt adsorption by the reconstruction of surface Ti ions, and Fig. 2 shows the formation energy (E) of Pt-DSA at various locations. f (Pt-DSA / TiO2) as precursor Pt 4+ Bulk Pt from ions 0 It is shown in comparison with cohesion.

[0079] Referring to Figures 1 and 2, computer calculations show that after light irradiation, the migration of bulk oxygen defects to the surface can occur together with a change in the oxidation number of nearby Ti, and this defect can be thermodynamically and kinetically favored. Spin density calculations show that a high density of magnetic moments (0.71 μ B ) with four-coordinated Ti next to the oxygen defect moved to the surface 3+ (4cTi) is generated. This induced 4cTi site is Pt 4+ can act as an active site for the bonding of Pt, and surface reconstruction occurs after bonding. Pt binding to this 4cTi site can be energetically highly favored (-1.96 eV) and shows a stronger thermodynamic preference than binding to other sites with the same surface oxygen vacancy. Pt 4+ Pt in bulk from 0 Considering the energy of the case of agglomeration (+1.52 eV), it can be said that the formation of Pt-DSA at the 4cTi site is preferred over the case of agglomeration of Pt atoms. Based on these theoretical calculation results, the present invention provides a mechanism for the synthesis of a photo-induced atomic dispersion catalyst using a TiO2 support. After light irradiation, excessive photo-excited charges can be concentrated on the surface under the photocatalytic hydrogen evolution reaction conditions, which causes bulk oxygen defects to move to the surface Ti 3+ -V O It induces pair formation. These Ti 3+ -V O The pairs are highly reactive, allowing metal atoms to selectively bind through specific metal-support interactions, and localized electrons induce surface reconstruction, resulting in the formation of stable atomically dispersed catalysts.

[0080]

[0081] Figure 3 shows an EPR spectrum for investigating Pt loading on photochemically generated defects in TiO2, and Figure 4 shows an EPR spectrum for investigating the air regeneration process of photoirradiated TiO2.

[0082] Referring to Figures 3 and 4, under an inert gas environment, anatase TiO2 exhibits electron-trapped O from bulk oxygen defects. - Ti associated with chemical species 3+ One electron paramagnetic resonance (EPR) signal corresponding to Ti is observed at g = 2.00. Irradiation with UV-visible light generates a new EPR signal at g = 1.97, which is associated with oxygen defects of different species. 3+It is believed that this is due to the formation of . The important point is that this new signal occurs along with the decrease of the existing signal, which is consistent with the photo-induced migration of oxygen defects suggested in the present invention. The color of TiO2 dispersed in a water-methanol solution changes from white to blue upon light irradiation, which indicates trap states where charges are concentrated. When a Pt precursor is added to the photo-activated TiO2, the blue color immediately disappears and the photo-induced EPR signal completely disappears, while the existing signal with a reduced intensity is simultaneously restored. When oxygen is added instead of the metal precursor to the photo-activated TiO2 solution, the photo-induced EPR signal disappears in the same manner, but in this case, the existing signal is restored to the same intensity as before the light irradiation. These results are in good agreement with the theoretical prediction that bulk oxygen vacancies are transported to the surface by photo-induced electrons, and these photo-induced oxygen vacancies can serve as reactive interfacial sites for the atomized metal atoms. Although not shown in the figure, Cs-STEM images and EDS elemental mapping show that uniform Pt atoms are dispersed on the TiO2 surface without the formation of Pt aggregates or nanoparticles. Illuminating a mixture of Pt precursor and TiO2 under the same light conditions confirms that severe Pt agglomeration occurs, indicating that pre-induced surface oxygen vacancies and electron charge accumulation in TiO2 are important for stable atomic incorporation of Pt into TiO2.

[0083]

[0084] Fig. 5 shows the EXAFS spectra of Pt-DSA / TiO2, Pt-NP / TiO2, PtO2, and Pt foil, Fig. 6 shows the XPS spectrum of Pt-DSA / TiO2, and Fig. 7 shows the XANES spectrum of Pt-DSA / TiO2. The Pt loading is 0.7 wt% in all samples. The valence state of Pt in Pt-DSA / TiO2 can be determined through extended X-ray absorption fine structure (EXAFS) analysis, X-ray photoelectron spectroscopy (XPS) analysis, and X-ray absorption near-edge structure (XANES) analysis.

[0085] Referring to FIGS. 5 to 7, the EXAFS spectrum of Pt-DSA / TiO2 is clearly distinguished from that of Pt-NP / TiO2, which is nanoparticles loaded on Pt foil or TiO2, and exhibits a distinct peak at 1.67 Å associated with the local coordination between Pt and O. The XPS spectrum of Pt-DSA / TiO2 shows that Pt exists in a divalent state, which is consistent with the results of the XANES spectrum. The peak of the white light intensity of the normalized absorption of XANES appears at approximately 11,568 eV, and the intensity at this time is between that of the Pt foil and PtO2.

[0086]

[0087] Although not shown in the drawing, Pt-DSA / TiO2 formed using the photochemical surface defect control method of the present invention was compared with Pt-SA / hydrogenated TiO2 formed by supporting metal atoms on a hydrogen-treated support using a conventional wet-impregnation method. It is known that hydrogen treatment at high temperatures induces surface disorder or defects. When commercial TiO2 is reduced at 500°C in a 10% H2 / Ar environment, only the EPR signal (g = 2.00) related to bulk oxygen defects is observed, and no surface oxygen defects are generated. When Pt is supported on TiO2 using the same precursor concentration and stabilization time as those used in the synthesis of Pt-DSA 0.7 wt% / TiO2, Pt δ+ (Pt + or Pt 3+ ) show distinct EPR signals associated with the Pt-DSA / TiO2. These EPR signals do not appear in the EPR data of Pt-DSA / TiO2, which suggests that the photochemical defect control method is not applicable to Pt, which is not measured in EPR. 2+ This is because it only induces the formation of Pt. In addition, the STEM image, EDS elemental mapping, and XPS data of Pt-SA / hydrogenated TiO2 show that a certain portion of Pt atoms can easily aggregate. In other words, the Pt loading in the Pt-DSA / TiO2 synthesis involves a specific interaction between the applied Pt atoms and reversible surface oxygen defects, which leads to the formation of specific Pt via dynamic surface reconstruction. 2+ On the other hand, Pt loading onto hydrogen-treated TiO2 involves irreversible surface disorder and non-specific interactions, which leads to mixed Pt states and agglomeration.

[0088]

[0089] Figure 8 shows an EPR spectrum for investigating Pt loading on photochemically generated defects in ZnO, and Figure 9 shows an EPR spectrum for investigating Pt loading on photochemically generated defects in CeO2.

[0090] Referring to Fig. 8, ZnO exhibits only an EPR signal at g = 1.956, which is related to singly ionized bulk oxygen defects within ZnO. These bulk oxygen defects decrease upon light irradiation because they migrate to the surface, and these surface oxygen defects exhibit an EPR signal at a slightly higher g value of 1.96. The surface oxygen defects disappear quickly upon Pt loading, and some of the bulk oxygen defects are restored. Air exposure experiments on photo-irradiated ZnO demonstrate that the atomic dispersion loading of Pt onto ZnO is due to the surface V formed by light irradiation. O , which is similar to the case where Pt is supported on the TiO2 surface (Pt-DSA / TiO2).

[0091] Referring to Fig. 9, various EPR signals are observed in the case of CeO2. These signals are each Ce 3+ (g = 1.87, 1.92, 2.09, 2.15), Ce 3+ -O - -Ce 4+ Surface defects (g = 1.96), O 2- (g = 2.03) indicates the presence of Ce. After light irradiation, Ce 3+ -O - -Ce 4+ Surface defects Ce 3+ It disappears with an increase in the signal, which means that oxygen defects are created on the CeO2 surface. When a Pt precursor is added to the light-irradiated CeO2, Ce is formed along with the support of Pt atoms. 3+The signal disappears immediately. The recovery of surface oxygen defects through air exposure confirms that the formed defects are used in the process of Pt atoms being deposited on the surface.

[0092]

[0093] Although not shown in the drawing, the atomic dispersion state and uniform distribution of Pt in Pt-DSA / ZnO and Pt-DSA / CeO2 can be confirmed by Cs-STEM and EDS mapping, XPS and XRD analyses, which demonstrate that the photochemical (photo-induced) surface defect control method of the present invention can be applied to the synthesis of atomic dispersion catalysts through various supports. In addition, it was confirmed that the photochemical surface defect control method of the present invention can be equally applied to the atomic dispersion support of Ir and Cu.

[0094]

[0095] Fig. 10 shows the hydrogen evolution reaction (HER) activity of the Pt-DSA / TiO2 photocatalyst at different amounts of Pt loading, Fig. 11 shows the hydrogen evolution reaction activity of the Pt-DSA / TiO2 photocatalyst and Pt-NP / TiO2 photocatalyst at different amounts of Pt loading, Fig. 12 shows the turnover frequency (TOF) of the hydrogen evolution reaction of the catalyst of Fig. 11, and Fig. 13 shows the results of measuring the hydrogen evolution reaction four times continuously at 1-hour intervals using the Pt-DSA / TiO2 photocatalyst and the Pt-SA / hydrogenated TiO2 photocatalyst.

[0096] Referring to Figs. 10 to 13, when methanol was used as a hole scavenger in a photocatalytic hydrogen evolution reaction, the hydrogen evolution performance of Pt-DSA / TiO2 was found to have a 1:1 correlation with the Pt loading amount (0.25 - 0.7 wt%). The measured performance exhibits a constant conversion frequency. This conversion frequency value is higher than that of any conventional catalysts with a promoter loading amount exceeding 0.1 wt%. The hydrogen generation rate of the Pt-DSA (0.7 wt%) / TiO2 catalyst showing the best activity was 164 mmol·g -1 ·h -1 This is a higher value than any other catalysts known so far, including a Pt atomically dispersed catalyst synthesized using TiO2 by a wet impregnation method (Pt-SA / TiO2), a catalyst in which Pt is supported on hydrogen-treated TiO2 by a wet impregnation method (Pt-SA / hydrogenated TiO2), and a catalyst in which Pt nanoparticles are physically attached to TiO2 (Pt-NP / TiO2).

[0097] Such high catalytic performance demonstrates the advantage of the specific interaction between Pt and TiO2 formed by the photochemical (photo-induced) atomic loading method of the present invention. The wet impregnation method used for the synthesis of Pt-SA / TiO2 and Pt-SA / hydrogenated TiO2 has limitations in enhancing catalytic performance due to low and inconsistent metal loading. In addition, catalysts prepared by the wet impregnation method have poor stability because Pt atoms are loaded with non-specific interactions on the irreversible surface disorder. In the case of nanoparticle catalysts, TOF decreases as the loading amount increases because the nanoparticles aggregate with each other or the local coordination between the metal and the support changes. Unlike these nanoparticle systems, the atomically dispersed catalyst of the present invention has an optimal atomically dispersed Pt coordination, which demonstrates that the formation of strong active interface sites through photoactivation plays an important role in ideal atom loading.

[0098]

[0099] Fig. 14 shows the initial yield of hydrogen generation through the photomodification of PET (poly(ethylene terephthalate)) using Pt-DSA / TiO2, Pt-SA / hydrogenated TiO2, and Pt-NP / TiO2, and Fig. 15 shows the results of the scale-up and long-term cyclic PET photomodification measurements of Pt-DSA / TiO2. Fig. 16 shows the conversion of PET to hydrogen in the photomodification of Pt-DSA / TiO2 of Fig. 14, and Fig. 17 schematically shows the PET photomodification using Pt-DSA / TiO2, and Fig. 18 shows the results of the PET photomodification reaction before and after 40 hours using Pt-DSA / TiO2. 1 H NMR spectrum is shown. A Pt-DSA / TiO2 catalyst was applied to the hydrogen production reaction through the photo-reforming reaction of PET (poly(ethylene terephthalate)) bottles, which can produce valuable energy sources and chemicals while reducing plastic waste.

[0100] Referring to FIGS. 14 to 18, the initial hydrogen generation amount generated by using PET as a hole scavenger for Pt-DSA / TiO2, Pt-SA / hydrogenated TiO2, and Pt-NP / TiO2 catalysts is compared, and the hydrogen generation performance of the Pt-DSA / TiO2 catalyst (2.14 mmol·g sub -1 ·h -1 ) was confirmed to be about twice as high as the hydrogen generation performance of Pt-SA / hydrogenated TiO2 and Pt-NP / TiO2 catalysts. In addition, as a result of long-term photo-modification experiments, the Pt-DSA / TiO2 catalyst showed a 98% reactant conversion rate during 40 hours of reaction. This conversion rate was calculated based on the chemical reaction formula, and the measured hydrogen generation amount was 1 The amount of consumed reactant calculated through H NMR measurement is stoichiometrically consistent with the amount of hydrogen generated calculated by substituting it into the chemical reaction equation. In addition, the NMR data show that the Pt-DSA / TiO2 catalyst can use ethylene glycol and terephthalic acid as reactants. The performance of the Pt-DSA / TiO2 catalyst (2.14 mmol g) in the PET bottle reforming reaction sub -1 ·h -1 , 42.2 mmol·g sub -1 ) is higher than the performance of previously known catalysts and has the required performance (4 mmol·g) to be used in hydrogen generation reaction through photo-reforming reaction at a practical stage. sub -1 ·h -1, it can be confirmed that it is closest to 50% conversion per day. In addition, cyclic measurement on a larger scale was performed to confirm the practicality and durability of the Pt-DSA / TiO2 catalyst. When the photo-reformation reaction was performed for 8 hours on a 100㎖ scale, 22.4㎖ (1 mmol H2) of hydrogen was produced, and the performance was maintained at more than 80% for three consecutive reaction cycles.

[0101]

[0102] We have discussed specific embodiments of the present invention. Those skilled in the art will appreciate that the present invention can be implemented in modified forms without departing from its essential characteristics. Therefore, the disclosed embodiments should be considered illustrative rather than restrictive. The scope of the present invention is set forth in the claims, not the foregoing description, and all differences within the scope equivalent thereto should be construed as being encompassed by the present invention.

[0103]

[0104] The atomically dispersed catalyst according to embodiments of the present invention can exhibit excellent performance. For example, the metal atoms of the atomically dispersed catalyst can be uniformly distributed on a metal oxide support, thereby increasing the utilization efficiency of the metal atoms and resulting in high catalytic activity. Furthermore, the metal atoms are attached to the metal oxide support through strong and specific chemical interactions, and because they possess a large number of electrons, they can exhibit excellent catalytic performance in reduction reactions (e.g., hydrogen evolution reactions). Furthermore, the atomically dispersed catalyst can be readily formed through a simple process without requiring high thermal energy.

Claims

1. Metal oxide support; and An atomic dispersion catalyst comprising metal atoms dispersed on the metal oxide support.

2. In paragraph 1, An atomic dispersion catalyst, characterized in that the metal oxide support comprises at least one of TiO2, ZnO, and CeO2.

3. In paragraph 1, An atomic dispersion catalyst, characterized in that the metal atoms include at least one of Pt, Ir, and Cu.

4. In paragraph 1, An atomic dispersion catalyst, characterized in that the metal atoms are dispersed on the surface of the metal oxide support.

5. In paragraph 1, The above atomic dispersion catalyst is, An atomic dispersion catalyst characterized by being formed by forming a metal oxide dispersion and a metal precursor solution, irradiating light to the metal oxide dispersion, and adding the metal precursor solution to the light-irradiated metal oxide dispersion.

6. In paragraph 5, An atomic dispersion catalyst characterized in that the light comprises UV-Vis light.

7. In paragraph 5, An atomic dispersion catalyst characterized in that oxygen defects are formed on the surface of the metal oxide by the light irradiation.

8. In paragraph 5, An atomic dispersion catalyst characterized in that oxygen defects inside the metal oxide move to the surface by the light irradiation.

9. Step of forming a metal oxide dispersion and a metal precursor solution; A step of irradiating light to the metal oxide dispersion; and A method for forming an atomic dispersion catalyst, comprising the step of adding a metal precursor solution to a metal oxide dispersion solution irradiated with light.

10. In paragraph 9, The above metal oxide dispersion is formed by placing a metal oxide in an organic aqueous solution and then performing ultrasonic treatment. The above metal oxide comprises at least one of TiO2, ZnO, and CeO2, A method for forming an atomic dispersion catalyst, characterized in that the organic aqueous solution comprises a methanol aqueous solution or an ethanol aqueous solution.

11. In paragraph 9, The above metal precursor solution is formed by diluting the metal precursor with water, A method for forming an atomic dispersion catalyst, characterized in that the metal precursor comprises at least one of H2PtCl6, H2IrCl6, and CuCl2.

12. In paragraph 9, A method for forming an atomic dispersion catalyst, characterized in that the light comprises UV-Vis light.

13. In paragraph 9, A method for forming an atomic dispersion catalyst, characterized in that oxygen defects are formed on the surface of the metal oxide by irradiating the light.

14. In paragraph 9, A method for forming an atomic dispersion catalyst, characterized in that oxygen defects inside the metal oxide move to the surface by irradiating the light.

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