Method for producing hydrogen peroxide by two-electron electrocatalytic water oxidation of calcium carbonate-based natural substance

Abstract

The invention discloses a method for producing hydrogen peroxide by two-electron electrocatalytic water oxidation of calcium carbonate-based natural substances, which comprises the following steps: (1) preparation of an anode material: loading the calcium carbonate-based natural substances such as egg shell powder, calcite powder, clam shell powder, coral powder and the like on a substrate through a naphthol binder to serve as the anode material; and (2) carrying out a reaction for synthesizing hydrogen peroxide by electro-catalysis water oxidation: constructing an electro-catalysis environment and electrochemical double cells, separating a cathode and an anode by a nafion membrane only allowing protons to pass through, taking a graphite sheet as the cathode, and taking a mixed solution of potassium carbonate and potassium bicarbonate as an electrolyte. And carrying out electro-catalysis water oxidation reaction to obtain a high-concentration hydrogen peroxide solution. The method simultaneously meets the requirements of resource utilization of the calcium carbonate waste and production of high-concentration hydrogen peroxide, and has the advantages of environmental friendliness and certain economic value.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrocatalytic water oxidation, and particularly relates to a method for producing hydrogen peroxide by electrocatalytic water oxidation of a calcium carbonate-based natural substance through a two-electron process. Background Art

[0002] As an important chemical substance, hydrogen peroxide is an important disinfectant that can effectively kill a variety of pathogenic microorganisms; as a green oxidant and bleaching agent, it is widely used in the fields of papermaking, textiles, wastewater treatment, chemical synthesis, etc. At present, the industrial production of hydrogen peroxide mainly relies on the anthraquinone method, which has a complex process flow, high energy consumption, and involves many side reactions. For a long time, frequent explosion and fire accidents in hydrogen peroxide production workshops worldwide have caused huge economic losses and casualties.

[0003] Currently, the electrochemical synthesis of H2O2 and its application in wastewater treatment have attracted wide attention. It includes the two-electron water oxidation (2e - WOR) method and the two-electron oxygen reduction reaction (2e - ORR) method. Among them, 2e - WOR only needs to use water as a reactant, which is much simpler than 2e - ORR. It does not need to utilize the oxygen dissolved in water, nor does it need to use a gas diffusion electrode, which is suitable for many anoxic environments. Therefore, electrocatalytic two-electron water oxidation to produce H2O2 shows great potential. In 2004, the work of producing H2O2 by 2e - WOR using a carbon-based catalyst in NaOH was first reported. Since then, most studies on 2e - WOR have focused on metal oxides. Relevant studies have pointed out that metal oxide electrodes are more commonly used in the anodic electro-synthesis of H2O2. Metal oxides commonly used as electrocatalysts for water oxidation to produce hydrogen peroxide include tungsten oxide (WO3), tin oxide (SnO2), titanium oxide (TiO2), bismuth vanadate (BiVO4), calcium titanate (CaSnO3), manganese oxide (MnOx), lanthanum oxide (La2O3), zirconium oxide (ZrO2), cobalt oxide (Co3O4), and alumina (Al2O3), etc. However, most of these metal oxides have relatively high raw material costs and complex preparation processes, which increase the cost of electrocatalytic water oxidation to synthesize hydrogen peroxide and are not conducive to large-scale industrial applications. Their production cycles are long, their yields are limited, and it is also difficult to meet the demand for catalyst yields in large-scale industrial applications. Some preparation processes have low utilization rates of raw materials and also cause waste of resources.

[0004] Natural substances are characterized by rich and renewable resources, environmental friendliness, low cost, unique active sites and catalytic properties. Calcium carbonate rocks (mainly calcium carbonate, with some dolomite) are widely distributed in the world. Calcite, eggshells, clam shells and coral powder mainly belong to calcium carbonate substances. Calcite tailings, eggshells, clam shells and coral remains are all waste materials and are often discarded as garbage. If not reasonably utilized, they will increase the volume and treatment cost of domestic waste. From the perspective of resource recovery and recycling, they all contain rich calcium carbonate components. Using them as anode materials for electrocatalytic water oxidation to produce hydrogen peroxide can achieve the sustainable development of the resource utilization and treatment of calcium carbonate-based natural substances. In addition, the arrangement of carbonate ions and calcium ions in calcium carbonate crystals has a certain regularity, and the indirect path in the electrocatalytic water oxidation to produce hydrogen peroxide is through the conversion of bicarbonate (HCO3 - ) to percarbonate (HCO4 - ) to generate H2O2. Using calcium carbonate-based materials as anode materials can achieve the effect of sufficient enrichment of carbonate ions (CO3 2 -) on the anode surface, thus greatly improving the yield of hydrogen peroxide. Summary of the Invention

[0005] In view of the urgent requirement for the resource utilization of calcium carbonate waste and the production of high-concentration hydrogen peroxide, the purpose of the present invention is to provide a method for the two-electron electrocatalytic water oxidation of calcium carbonate-based natural substances to produce hydrogen peroxide. The method of the present invention has the advantages of simple equipment, convenient operation, low cost, environmental friendliness, etc.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for the two-electron electrocatalytic water oxidation of calcium carbonate-based natural substances to produce hydrogen peroxide, the method comprising the following steps:

[0008] (1) Preparation of the electrocatalytic water oxidation anode material:

[0009] Add naphthol binder to calcium carbonate-based natural substances such as eggshell powder, calcite powder, clam shell powder, coral powder, etc. After ultrasonic mixing of the above solution, load it on the substrate material as the anode;

[0010] (2) Carry out the electrocatalytic water oxidation synthesis of hydrogen peroxide reaction:

[0011] Set up an electrocatalytic environment, an electrochemical two-compartment cell, with the anode and cathode separated by a Nafion membrane that only allows protons to pass through. The anode is a carbon paper loaded with a calcium carbonate-based natural material, and the cathode is a graphite sheet. The electrolyte is a mixture of 3M potassium carbonate and 1M potassium bicarbonate. Subsequently, an electrocatalytic water oxidation reaction is carried out at 2.8 V versus RHE for 30 min. During the reaction process, it is fully stirred, and a high-concentration hydrogen peroxide (H2O2) solution can be obtained.

[0012] Preferably, in the step (1), the anode material for electrocatalytic water oxidation is a carbon-based material loaded with natural substances such as 100-mesh eggshell powder, calcite powder, clam shell powder, and coral powder as electrodes. Among them, these natural substances, as water oxidation materials, are mixed with a naphthol binder solution in a ratio of 0.07 mg:1 μL and ultrasonicated for 5 min to make the solution evenly mixed. The prepared solution is drop-coated on the carbon-based material.

[0013] Preferably, all the raw materials of the anode material in the step (1) are untreated natural materials.

[0014] Preferably, in the step (2), the electrocatalytic reaction time is 30 min.

[0015] Preferably, in the step (2), the device is an electrochemical two-compartment cell, with the anode and cathode separated by a Nafion membrane that only allows protons to pass through, and the electrocatalytic water oxidation voltage is 2.8 V versus RHE.

[0016] Preferably, in the step (2), the electrolyte in the electrocatalytic environment is a mixture of 3M potassium carbonate and 1M potassium bicarbonate.

[0017] Preferably, in the step (2), the volume of the electrolyte is 20 ml.

[0018] Preferably, in the step (2), the setting is 300 revolutions per minute and the stirring time is 1 hour.

[0019] Compared with the prior art, the present application has the following advantages:

[0020] (1) Using H2O widely present in the environment as raw materials, only inexpensive carbonates and bicarbonates are required as electrolytes to carry out an electrocatalytic two-electron water oxidation reaction. It has the advantages of rapid on-site preparation and low green energy consumption;

[0021] (2) Resourcefully utilizing calcium carbonate-based natural substances as anode materials for electrocatalytic water oxidation to synthesize hydrogen peroxide, which has environmental friendliness and certain economic value.

[0022] (3) The reaction can occur at normal temperature and pressure, and can efficiently and rapidly synthesize a high-concentration hydrogen peroxide. Brief Description of the Drawings

[0023] Figure 1 X-ray diffraction patterns of calcium carbonate-based natural materials and standard calcium carbonate cards.

[0024] Figure 2 Yield graph of electrocatalytic water oxidation to produce hydrogen peroxide by calcium carbonate-based natural materials at 2.8 V versus RHE voltage;

[0025] Figure 3 Productivity graph of electrocatalytic water oxidation to produce hydrogen peroxide by calcium carbonate-based natural materials at 2.8 V versus RHE voltage;

[0026] Figure 4 Faraday efficiency graph of electrocatalytic water oxidation to produce hydrogen peroxide by calcium carbonate-based natural materials at 2.8 V versus RHE voltage;

[0027] The realization, functional features and advantages of the purpose of this application will be further described in combination with embodiments with reference to the accompanying drawings. Detailed implementation manners

[0028] The following will further describe the present invention in combination with the accompanying drawings. It should be noted that the following embodiments are based on this technical solution, and detailed implementation manners and specific operation processes are given, but the protection scope of the present invention is not limited to this embodiment.

[0029] Example 1

[0030] Prepare an electrode for electrocatalytic water oxidation of calcium carbonate-based natural substances:

[0031] Crush eggshells, calcite, clam shells, and corals into 100 meshes respectively with a crusher. Use the natural substances such as 100-mesh eggshell powder, calcite powder, clam shell powder, and coral powder as electrodes. Among them, these natural substances are mixed with a naphthol solution as a water oxidation material in a ratio of 16.7 mg:234 μL, and ultrasonicated for 5 min to make the solution evenly mixed. Drop the prepared solution onto a 0.5 cm 2 carbon paper material to prepare an anode electrode sheet.

[0032] The X-ray diffraction pattern is as Figure 1 shown. It can be seen that: eggshell powder and calcite powder are calcite-type calcium carbonate, and clam shell powder and coral powder are aragonite-type calcium carbonate.

[0033] Example 2

[0034] Use calcium carbonate-based natural substances as the anode to electrocatalytically oxidize water to synthesize hydrogen peroxide:

[0035] Step 1: Use natural substances such as eggshell powder, calcite powder, clam shell powder, and coral powder with a mesh size of 100 as electrodes. Among them, these natural substances are used as water oxidation materials and mixed with naphthol solution in a ratio of 16.7 mg: 234 μL, and ultrasonicated for 5 min to make the solution evenly mixed. The prepared solution is drop-coated on a 0.5 cm 2 carbon paper material to prepare an anode electrode sheet.

[0036] Step 2: Set up an electrocatalytic environment, an electrochemical two-compartment cell, separate the anode and cathode through a nafion membrane that only allows protons to pass through. The anode is a carbon paper loaded with calcium carbonate-based natural material, the cathode is a graphite sheet, and the electrolyte is a mixed solution of 3M potassium carbonate and 1M potassium bicarbonate. Subsequently, electrocatalytic water oxidation reaction is carried out at 2.0 - 3.2 V versus RHE for 30 min. During the reaction process, stir thoroughly at a stirring speed of 300 revolutions per minute for 30 min, and take samples at 1 min, 2 min, 5 min, 10 min, 15 min, 20 min, 25 min, and 30 min. Obtain water sample 1-1.

[0037] Step 3: Use an ultraviolet-visible spectrophotometer and the potassium titanate oxalate detection method to detect the absorbance of hydrogen peroxide in the water sample 1-1 obtained in Step 2.

[0038] The production results are as Figure 2 shown, the yield results are as Figure 3 shown, and the Faraday efficiency is as Figure 4 shown. It can be seen that:

[0039] Using calcium carbonate-based natural substances as anode materials for electrocatalytic water oxidation, the production of hydrogen peroxide is continuously increasing with time. The production of coral powder, clam powder, calcite, and eggshell can reach 59.7 mM, 53.1 mM, 40.1 mM, and 28.3 mM respectively. The yields can reach 73.74 μmol / cm 2 / min, 93.38 μmol / cm 2 / min, 138.58 μmol / cm 2 / min, 108.9 μmol / cm 2 / min respectively, and the Faraday efficiencies can reach 63.68%, 87.39%, 96.87%, and 98.82% respectively.

[0040] Therefore, this method can achieve efficient production of high-concentration hydrogen peroxide.

[0041] In summary, it can be seen that compared with the artificially synthesized metal oxides with complex preparation processes, the method described in this application uses calcium carbonate-based natural substances widely present in the environment as the anode material for electrocatalytic water oxidation to produce hydrogen peroxide. With the assistance of cheap and easily available carbonates and bicarbonates, high-concentration hydrogen peroxide can be rapidly prepared on-site, with high resource utilization rate and great practical application prospects.

[0042] For those skilled in the art, various corresponding changes and deformations can be given according to the above technical solutions and concepts, and all such changes and deformations should be included within the protection scope of the claims of the present invention.

Claims

1. A method for producing hydrogen peroxide by two-electron electrocatalytic water oxidation using calcium carbonate-based natural substances, the method comprising the following steps: (1) Preparation of the anode material for electrocatalytic water oxidation: Adding a naphthol binder to calcium carbonate-based natural substances such as eggshell powder, calcite powder, clam shell powder, and coral powder, ultrasonically mixing the above solutions evenly, and then loading them on a substrate material to serve as the anode; (2) Conducting the electrocatalytic water oxidation reaction to synthesize hydrogen peroxide: Set up an electrocatalytic environment, an electrochemical two-compartment cell, separate the anode and cathode by a nafion membrane that only allows protons to pass through. The anode is a carbon paper loaded with calcium carbonate-based natural substance material, the cathode is a graphite sheet, and the electrolyte is a mixed solution of 3M potassium carbonate and 1M potassium bicarbonate. Subsequently, conduct the electrocatalytic water oxidation reaction at 2.0 - 3.2V versus RHE for 30 min, and stir well during the reaction process to obtain a high-concentration hydrogen peroxide (H2O2) solution.

2. The method for electrocatalytic water oxidation to produce hydrogen peroxide using a calcium carbonate-based natural substance as an electrode according to claim 1, characterized in that, In the step (1), the anode in the electrocatalytic environment is loaded with natural substances such as 100-mesh eggshell powder, calcite powder, clam shell powder, and coral powder as the electrode.

3. The method for electrocatalytic water oxidation to produce hydrogen peroxide using a calcium carbonate-based natural substance as an electrode according to claim 1, characterized in that, In the step (1), the natural substance as the water oxidation material is mixed with a naphthol solution in a ratio of 0.07 mg:1 μL, ultrasonically treated for 5 min to mix the solution evenly, and the prepared solution is drop-coated on the substrate material to prepare the anode electrode sheet.

4. The method for electrocatalytic water oxidation to produce hydrogen peroxide using a calcium carbonate-based natural substance as an electrode according to claim 1, characterized in that, In the step (1), the raw materials of the anode material are all untreated natural materials.

5. The method for electrocatalytic water oxidation to produce hydrogen peroxide using a calcium carbonate-based natural substance as an electrode according to claim 1, wherein In the step (2), the electrocatalytic reaction time is 30 min.

6. The method for electrocatalytic water oxidation to produce hydrogen peroxide using a calcium carbonate-based natural substance as an electrode according to claim 1, wherein In the step (2), the device is an electrochemical two-compartment cell, the anode and cathode are separated by a nafion membrane that only allows protons to pass through, and the electrocatalytic water oxidation voltage is 2.8V versus RHE.

7. The method for electrocatalytic water oxidation to produce hydrogen peroxide using a calcium carbonate-based natural substance as an electrode according to claim 1, wherein In the step (2), the electrolyte in the electrocatalytic environment is a mixed solution of 3M potassium carbonate and 1M potassium bicarbonate.

8. The method for electrocatalytic water oxidation to produce hydrogen peroxide using a calcium carbonate-based natural substance as an electrode according to claim 1, characterized in that, In the step (2), the volume of the electrolyte is 20 ml.

9. The method for electrocatalytic water oxidation to produce hydrogen peroxide using a calcium carbonate-based natural substance as an electrode according to claim 1, wherein, In the step (2), set the rotation speed to 300 revolutions per minute and the stirring time to 30 minutes.

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