A method for the efficient spontaneous preparation of H2O2 using low-valence elements molybdenum and palladium.

Abstract

The application belongs to the technical field of hydrogen peroxide preparation, and particularly relates to a method for efficiently and spontaneously preparing H2O2 by using low-valence element molybdenum and palladium. Molybdenum powder and palladium chloride are added into oxygen-containing water, and the strong reduction capacity of the molybdenum powder is used to reduce the palladium ions in the solution into palladium single substance and load the palladium single substance on the surface of the molybdenum powder. The molybdenum powder is used as a carrier and an electron donor, and the palladium single substance is used as an active site. Through the synergistic effect between the molybdenum powder and the palladium single substance, the oxygen widely existing in nature is reduced into H2O2. The method for preparing H2O2 is a spontaneous reaction occurring under natural conditions, does not need to input photoelectric energy, does not need to add complex chemical reagents, and can generate H2O2 only by oxygen, and has the excellent characteristics of convenient and efficient preparation of H2O2.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen peroxide preparation technology, specifically relating to a method for the efficient spontaneous preparation of H2O2 using low-valence elements molybdenum and palladium. Background Technology

[0002] Hydrogen peroxide (H2O2) is considered one of the greenest and most environmentally friendly oxidants, and is widely used in disinfection, chemical synthesis, environmental remediation, papermaking, and fuel cells. The mainstream technologies for H2O2 preparation include the anthraquinone process, electrocatalysis, photocatalysis, and direct hydrogen-oxygen synthesis. Currently, over 95% of the world's H2O2 originates from the anthraquinone process; however, this process is energy-intensive, requires complex equipment and chemical reagents, and the generated H2O2 cannot be used in situ, posing certain safety risks.

[0003] In-situ generation and utilization of H2O2 has garnered widespread attention and popularity due to the elimination of the need for H2O2 storage and transportation, the absence of concerns about H2O2 decomposition, and the lack of dilution. Currently, photocatalysis, electrocatalysis, and direct hydrogen-oxygen synthesis can all effectively produce H2O2 in situ. Photocatalysis utilizes sunlight to excite semiconductors, generating photogenerated electrons to reduce oxygen and produce H2O2. However, this technology suffers from severe recombination of photogenerated electron-hole pairs, resulting in low H2O2 concentrations, and is also affected by factors such as weather, water color, and time zone variations. For example, Chinese invention patent CN 113181945 B discloses a method for preparing a highly efficient composite photocatalyst for hydrogen peroxide production, but the H2O2 yield of this catalyst under simulated sunlight is only 57 μmolg. -1 h -1 The concentration of H2O2 produced is far below the requirements of practical applications. Electrocatalysis is a technology that uses the cathode to reduce oxygen to H2O2 or the anode to oxidize water to H2O2. Although electrocatalysis produces a high concentration of H2O2 that meets the needs of practical applications, it requires complex equipment, electrode materials, electrolytes, and valuable electricity. For example, Chinese invention patent CN 116676620 A discloses a method for preparing a Co single-atom catalyst and its application in the electrocatalytic reduction of oxygen to produce H2O2. However, this catalyst is a single-atom material, making its preparation difficult; the production of H2O2 uses sulfuric acid as an electrolyte, which easily corrodes the equipment; and the operating voltage is 0.06V, resulting in high energy consumption. The direct synthesis of hydrogen and oxygen is a technology that uses hydrogen and oxygen to directly generate H2O2 under the action of a noble metal catalyst. This technology produces a high concentration of H2O2, but the production cost is expensive and there are potential safety hazards.

[0004] In summary, photocatalysis, electrocatalysis, and direct hydrogen-oxygen synthesis all have numerous shortcomings in the in-situ preparation of H2O2. Therefore, there is an urgent need to develop a novel, safe, efficient, environmentally friendly, and sustainable in-situ H2O2 preparation technology. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, this invention provides a method for the efficient spontaneous preparation of H2O2 using low-valence elements molybdenum and palladium. This method has the advantages of requiring no photoelectric energy input, simple equipment, low cost, environmental friendliness, being unaffected by weather, not being limited by site, and being applicable to a wide range of actual water bodies, and has high practical application value.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] This invention provides a method for the efficient spontaneous preparation of H2O2 using low-valence elements molybdenum and palladium. Specifically, molybdenum powder and palladium ions are added to oxygenated water. The molybdenum powder reduces the palladium ions in the water to elemental palladium, which is then loaded onto the surface of the molybdenum powder. The molybdenum powder is used as a carrier and electron donor, and elemental palladium is used as an active site. Through the synergistic effect between the molybdenum powder and elemental palladium, the oxygen in the water is reduced to H2O2.

[0008] This invention utilizes Mo / Pd 2+ The system reduces oxygen to produce H2O2, achieving a yield of up to 10059.7 μmol·g. -1 ·h -1 This is higher than most photocatalysts currently reported (exceeding 10000 μmol·g⁻¹). -1 ·h -1 (The photocatalyst is extremely rare). More importantly, the method for preparing H2O2 in this invention is a spontaneous reaction that occurs under natural conditions, requiring no input of photoelectric energy or the addition of complex chemical reagents; it can be produced as long as oxygen is present. Therefore, the method of this invention possesses the excellent characteristics of convenient, rapid, and efficient preparation of H2O2.

[0009] Preferably, the dissolved oxygen concentration in the oxygenated water body is 8.2–29.8 mg / L. Wherein, 8.2 mg / L is the saturated dissolved oxygen concentration in an air atmosphere, and 29.8 mg / L is the saturated dissolved oxygen concentration in an oxygen-rich atmosphere.

[0010] Preferably, the amount of molybdenum powder added is 0.2 to 1.5 g / L.

[0011] Preferably, the palladium ions are derived from palladium chloride, and the concentration of the palladium ions is 0.2–2 mM.

[0012] Preferably, the water body includes ultrapure water, tap water, lake water, river water, and seawater. Although the interfering ions in tap water, lake water, river water, and seawater can significantly interfere with the Mo / Pd ratio. 2+ Despite the reduced activity of the system, it can still convert oxygen in actual water bodies into H2O2 without the input of photoelectric energy, providing a new, more convenient, and effective method for the preparation of H2O2.

[0013] Preferably, the pH range of the aerobic water is pH 2 to pH 10. This invention utilizes Mo / Pd... 2+ The method of reducing oxygen to produce H2O2 is applicable to a wide pH range (pH2-pH10), thus overcoming the scientific challenge of producing H2O2 under neutral and alkaline conditions.

[0014] A second aspect of the present invention provides a catalyst for preparing H2O2, the catalyst comprising molybdenum powder and palladium ions.

[0015] The third aspect of the present invention provides the application of the catalyst described in the second aspect in the degradation of environmental pollutants in aerobic water bodies.

[0016] Hydrogen peroxide (H2O2) is a strong oxidant that can be used to degrade pollutants in the environment. This invention utilizes Mo / Pd... 2+ The method of reducing oxygen to produce H2O2 is an in-situ spontaneous reaction, and therefore can be directly applied in-situ to the degradation and removal of environmental pollutants.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] This invention discloses a method for the efficient spontaneous preparation of H₂O₂ using low-valence elements molybdenum and palladium. Molybdenum powder and palladium chloride are added to oxygenated water. Utilizing the strong reducing ability of molybdenum powder, palladium ions in the solution are reduced to elemental palladium, which is then loaded onto the surface of the molybdenum powder. Using molybdenum powder as a carrier and electron donor, and elemental palladium as an active site, the synergistic effect between the molybdenum powder and elemental palladium reduces oxygen, which is widely present in nature, to H₂O₂. This invention has the following advantages:

[0019] (1) This invention utilizes Mo / Pd 2+ The method of reducing oxygen to produce H2O2 is a spontaneous reaction that occurs under natural conditions. It does not require the consumption of precious electrical energy, nor does it require the addition of other chelating agents or chemical reagents; only oxygen is needed.

[0020] (2) This invention utilizes Mo / Pd 2+ The method of reducing oxygen to produce H2O2 has the advantages of low cost, environmental friendliness, wide availability, no weather impact, all-weather operation, operation under a wide pH range, and operation in actual natural water bodies.

[0021] (3) This invention utilizes Mo / Pd 2+ The system reduces oxygen to produce H2O2, achieving a yield of up to 10059.7 μmol·g. -1 ·h -1 It can be directly applied in situ to the degradation and removal of environmental pollutants. Attached Figure Description

[0022] Figure 1 for Mo / Pd 2+ Performance diagram of the system reducing oxygen to produce H2O2;

[0023] Figure 2 The XRD patterns of Mo before and after the reaction are shown.

[0024] Figure 3 for Mo / Pd 2+ Performance graph of the system reducing oxygen to produce H2O2 under different pH conditions;

[0025] Figure 4 for Mo / Pd 2+ Performance diagram of the system in reducing oxygen to produce H2O2 in different water bodies. Detailed Implementation

[0026] The specific embodiments of the present invention will be further described below. It should be noted that these descriptions are for the purpose of aiding understanding the present invention, but do not constitute a limitation thereof. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0027] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the experimental materials used in the following embodiments are all available through conventional commercial channels.

[0028] Example 1: Mo / Pd 2+ Performance determination of the system in reducing oxygen to produce H2O2

[0029] (1) Prepare the colorimetric reagent for H2O2 concentration determination:

[0030] 1) Buffer solution: 0.84g Na2HPO4 + 6.04g NaH2PO4 + 100mL H2O;

[0031] 2) N,N-Diethyl-1,4-phenylenediamine (DPD) reagent: 0.1g DPD + 200uL 5M H2SO4 + 9.8mL H2O;

[0032] 3) Horseradish catalase (POD) reagent: 10 mg POD dissolved in 10 mL of ultrapure water.

[0033] (2) Determination of Mo / Pd 2+ The system's ability to reduce oxygen to produce H2O2:

[0034] 1) Place 60 mL of ultrapure water in a 100 mL beaker, add 0.4 g / L Mo and 1 mM PdCl2, then introduce oxygen (flow rate of 50 mL / min), stir to mix, and start timing. Set the sampling time to 0, 2, 5, 10, 15, and 20 min, and take 2 mL of liquid sample at each set time gradient, filter, and save the filtrate for analysis.

[0035] 2) Take a 2 mL centrifuge tube, add 1.7 mL of the buffer solution prepared in step (1), 50 μL of the DPD reagent prepared in step (1), 50 μL of the POD reagent prepared in step (1), and then add 100 μL of the above filtrate. After color development for 30 s, use a UV-Vis spectrophotometer to determine the H2O2 concentration in the filtrate.

[0036] The results are as follows Figure 1 As shown, it can be seen that:

[0037] Molybdenum powder (Mo) alone and palladium chloride (Pd) alone 2+ Neither Mo nor Pd has the ability to reduce oxygen to produce H2O2. Furthermore, Mo / Pd 2+ The system cannot produce H₂O₂ under argon (Ar) conditions, but it can effectively produce H₂O₂ under air (Air) and oxygen (O₂) conditions. Specifically, the yield of H₂O₂ under air conditions reaches 3542.8 μmol g. -1 h -1 Under oxygen conditions, the yield of H2O2 is as high as 10059.7 μmol g. -1 h -1 This is far higher than most reported photocatalytic reactions and electrocatalytic technologies. This indicates that Mo / Pd... 2+ The system exhibits excellent activity in oxygen reduction to produce H2O2.

[0038] In addition, the XRD patterns of Mo before and after H2O2 production were tested: Particulate matter in the solution after the reaction in Example 1 was separated, washed with water, washed with alcohol, and dried to obtain the sample of Mo after H2O2 production. Then, XRD diffraction characterization of Mo was performed before and after the reaction, and the results are as follows. Figure 2 As shown, it can be seen that:

[0039] The Mo used was elemental molybdenum, and its XRD standard card is PDF#42-1120. After Mo produces H₂O₂, it is clear that elemental Pd is bound to the Mo surface; the standard card for elemental Pd is PDF#46-1043. This indicates that Mo first binds Pd in ​​the solution... 2+ The oxygen is reduced to elemental Pd, and then elemental Pd is used as the active site for reducing oxygen to H2O2. Mo acts as the carrier and electron donor of Pd. Through the synergistic effect of Mo and Pd, the system can continuously and efficiently reduce oxygen to produce H2O2.

[0040] Example 2: Mo / Pd 2+ Performance determination of the system in reducing oxygen to produce H2O2 in water bodies with different pH values

[0041] (1) Prepare the colorimetric reagent for H2O2 concentration determination (the preparation method is the same as in Example 1).

[0042] (2) Prepare water samples with different pH values:

[0043] Take five 100mL beakers and add 60mL of ultrapure water to each. Then, use 0.1M H2SO4 and 0.1M NaOH to adjust the pH of the solutions in the five beakers to pH2, pH4, pH6, pH8, and pH10, respectively.

[0044] (3) Determination of Mo / Pd under different pH conditions 2+ The system's ability to reduce oxygen to produce H2O2:

[0045] 1) Add 0.4 g / L Mo and 1 mM PdCl2 to the five beakers in step (2), then introduce oxygen, stir and mix well, and start timing. Set the sampling time to 0, 2, 5, 10, 15, 20 min, and take 2 mL of liquid sample at the set time gradient, filter, save the filtrate, and wait for testing.

[0046] 2) Take a 2 mL centrifuge tube, add 1.7 mL of the buffer solution prepared in step (1), 50 μL of the DPD reagent prepared in step (1), 50 μL of the POD reagent prepared in step (1), and then add 100 μL of the above filtrate. After color development for 30 s, use a UV-Vis spectrophotometer to determine the H2O2 concentration in the filtrate.

[0047] The results are as follows Figure 3 As shown in the figure:

[0048] Mo / Pd 2+ The system can effectively reduce oxygen to H2O2 within a wide pH range (pH2-pH10), indicating that Mo / Pd 2+The system overcomes the scientific challenge of producing H2O2 under neutral and alkaline conditions.

[0049] Example 3: Mo / Pd 2+ Determination of the system's activity in reducing oxygen to produce H2O2 in different natural water bodies

[0050] (1) Prepare the colorimetric reagent for H2O2 concentration determination (the preparation method is the same as in Example 1).

[0051] (2) Collection of natural water body samples:

[0052] Five natural water samples were collected, including ultrapure water, tap water, river water, lake water, and seawater. The ultrapure water was obtained from an ultrapure water system in the laboratory, the tap water from Sun Yat-sen University, the river water from the Pearl River, the lake water from the central lake of Guangzhou University Town, and the seawater from Yangjiang.

[0053] (3) Determination of Mo / Pd 2+ The system's ability to reduce oxygen to produce H2O2 in different natural water bodies:

[0054] 1) Take five 100mL beakers and fill them with 60mL each of ultrapure water, tap water, river water, lake water, and seawater, respectively. Then add 0.4g / L Mo and 1mM PdCl2 to the five beakers respectively, introduce oxygen, stir and mix well, and start timing. Set the sampling time to 0, 2, 5, 10, 15, and 20 min, and take 2mL of liquid sample at each of the set time gradients, filter, and save the filtrate for analysis.

[0055] 2) Take a 2 mL centrifuge tube, add 1.7 mL of the buffer solution prepared in step (1), 50 μL of the DPD reagent prepared in step (1), 50 μL of the POD reagent prepared in step (1), and then add 100 μL of the above filtrate. After color development for 30 s, use a UV-Vis spectrophotometer to determine the H2O2 concentration in the filtrate.

[0056] The results are as follows Figure 4 As shown in the figure:

[0057] Mo / Pd 2+ The system exhibited the best activity in reducing oxygen to H₂O₂ in ultrapure water, followed by tap water, lake water, river water, and seawater. This is because ultrapure water does not contain interfering ions, while tap water, lake water, river water, and seawater all contain many interfering ions, especially seawater which is rich in minerals. The presence of these interfering substances can significantly interfere with the Mo / Pd ratio. 2+ The activity of the system. Admittedly, although Mo / Pd 2+The system's activity in producing H2O2 in actual water bodies is somewhat suppressed, but the result is still ideal, because it is very difficult to convert oxygen in actual water bodies into H2O2 without photovoltaic energy input.

[0058] As can be seen from the above embodiments, compared with existing H2O2 preparation technologies, the present invention utilizes Mo / Pd 2+ The method for reducing oxygen to produce H₂O₂ requires no light or electrical energy, no other chemical reagents, and is unaffected by weather or location. Furthermore, the yield of H₂O₂ produced using this method can reach as high as 10059.7 μmol·g. -1 ·h -1 Furthermore, the method of this invention is a spontaneous reaction that can occur under natural conditions and is applicable to a wide pH range and complex real-world water bodies. Therefore, this invention utilizes Mo / Pd 2+ The method of reducing oxygen to produce H2O2 has high practical application value.

[0059] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and these variations still fall within the protection scope of the present invention.

Claims

1. A method for the efficient spontaneous preparation of H2O2 using low-valence elements molybdenum and palladium, characterized in that, Molybdenum powder and palladium ions are added to oxygenated water. The molybdenum powder reduces the palladium ions in the water to elemental palladium, which is then loaded onto the surface of the molybdenum powder. The molybdenum powder is used as a carrier and electron donor, and the elemental palladium is used as an active site. Through the synergistic effect between the molybdenum powder and elemental palladium, the oxygen in the water is reduced to H2O2.

2. The method for efficiently and spontaneously preparing H2O2 using low-valence elements molybdenum and palladium according to claim 1, characterized in that, The dissolved oxygen concentration in the oxygenated water body is 8.2–29.8 mg / L.

3. The method for efficiently and spontaneously preparing H2O2 using low-valence elements molybdenum and palladium according to claim 1, characterized in that, The dosage of molybdenum powder is 0.2–1.5 g / L.

4. The method for efficiently and spontaneously preparing H2O2 using low-valence elements molybdenum and palladium according to claim 1, characterized in that, The palladium ions are derived from palladium chloride, and the concentration of the palladium ions is 0.2–2 mM.

5. The method for efficiently and spontaneously preparing H2O2 using low-valence elements molybdenum and palladium according to claim 1, characterized in that, The water bodies include ultrapure water, tap water, lake water, river water, and seawater.

6. The method for efficiently and spontaneously preparing H2O2 using low-valence elements molybdenum and palladium according to claim 1, characterized in that, The pH range of the oxygenated water is pH2 to pH10.

7. A catalyst for preparing H2O2, characterized in that, The catalyst comprises molybdenum powder and palladium ions.

8. The application of the catalyst according to claim 7 in the degradation of environmental pollutants in aerobic water bodies.

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