CN114672824A - A kind of electrolysis method for producing high-purity hydrogen peroxide - Google Patents

Abstract

The invention discloses an electrolysis method for producing high-purity hydrogen peroxide. The oxide single wafer is used as the anode material of the electrolytic cell, and the carbon-based material is used as the cathode material. After the oxygen is introduced, a bias voltage is applied to the anode and the cathode of the electrolytic cell, so that the anode undergoes a two-electron water oxidation reaction to generate hydrogen peroxide, and at the same time, the cathode undergoes an oxygen reduction reaction to generate hydrogen peroxide. Compared with the prior art, this method replaces the proton reduction reaction that occurs at the cathode with a two-electron oxygen reduction reaction, and directly converts hydrogen into hydrogen peroxide, which solves the storage and utilization problems of the by-product hydrogen; single target product peroxide Hydrogen is simultaneously generated at the anode and cathode, which greatly increases the added value of the product; the use of the two-electron oxygen reduction reaction further reduces the applied bias voltage and improves the power utilization efficiency.

Description

A kind of electrolysis method for producing high-purity hydrogen peroxide

technical field

The invention relates to the technical field of hydrogen peroxide preparation, in particular to an electrolysis method for producing high-purity hydrogen peroxide by using ultrapure water and oxygen as raw materials.

Background technique

Hydrogen peroxide aqueous solution, commonly known as hydrogen peroxide, is an important chemical raw material with clean and non-polluting properties. It is widely used in printing and dyeing, papermaking, environmental protection, food, chemical synthesis and semiconductor industries. Hydrogen peroxide is usually divided into industrial grade, food grade, reagent grade and electronic grade. Among them, ultra-clean and high-purity electronic grade hydrogen peroxide is one of the indispensable key materials in the microfabrication process of semiconductor technology, mainly used in chip manufacturing. In the process links such as grinding, oxidation, etching and cleaning, its purity seriously affects the electrical performance, reliability and yield of integrated circuits.

The industrial production methods of hydrogen peroxide include barium peroxide method, ammonium persulfate method (electrolysis method), anthraquinone method, isopropanol method and oxygen cathode reduction method. Among them, the anthraquinone method is the current mainstream industrial production method at home and abroad, and its total chemical reaction equation is H ₂ + O ₂ = H ₂ O ₂ ; its advantages are mature technology, high degree of automation control, low raw material cost and energy consumption , suitable for large-scale production, its disadvantage is that there is a bottleneck in the supply of raw materials (mainly hydrogen), the production process is complex, and the product purity is low. At present, electronic grade hydrogen peroxide is obtained by using industrial grade hydrogen peroxide produced by anthraquinone method as raw material, and then deeply purified by techniques such as rectification, ion exchange resin, membrane separation and supercritical extraction. Oxygen cathodic reduction is an electrochemical method in which an oxygen evolution reaction (4OH ^‒ → O ₂ + 2H ₂ O + 4 e ^‒ ) occurs at the anode and a two-electron oxygen reduction reaction (2O ₂ + 2H ) occurs at the cathode under strong alkaline conditions. ₂ O+ 4 e ^‒ → 2HO ₂ ^‒ + 2OH ^‒ ), the overall chemical reaction equation is O ₂ + 2OH ^‒ → 2HO ₂ ^‒ or O ₂ + 2H ₂ O → 2H ₂ O ₂ ; Small-scale on-site production, the disadvantage is that the anode catalyst is noble metal Pt, RuO ₂ , etc., the cost is high, and the produced hydrogen peroxide has poor stability (according to the literature: Gustaaf Goor et al ., Hydrogen Peroxide in Ullmann's Encyclopedia of Industrial Chemistry , Wiley-VCH , Weinheim, Germany, 2019).

Another electrochemical method, the anode material uses bismuth vanadate single crystal to maximize the catalytic activity and selectivity of the water oxidation reaction, and the cathode material uses a nickel-based alloy; under alkaline conditions, the anode undergoes a two-electron water oxidation reaction ( 2H ₂ O → H ₂ O ₂ + 2H ⁺ + 2 e ^‒ ), the hydrogen evolution reaction occurs at the cathode (2H ⁺ + 2 e ^‒ → H ₂ ), and the overall chemical reaction equation is 2H ₂ O → H ₂ O ₂ + H ₂ ; Since this water anodic oxidation method uses bismuth vanadate single crystal as the core catalyst, it can be called bismuth vanadate method or single crystal electrocatalysis method; its advantages are high current efficiency, low cost and high product purity, and its disadvantage is that the cathode precipitates The added value of hydrogen is low, and it is inconvenient to store and utilize (according to the literature: the patent title applied by the inventor Li Guoling is "An Electrolysis Method for Low-cost Production of High-purity Hydrogen Peroxide and Hydrogen", the patent application number is 201610567960.5 Chinese invention patent application).

Compared with the anthraquinone method, the raw materials (water and oxygen) required by the oxygen cathode reduction method and the bismuth vanadate method are low in price, sufficient in supply and controllable in purity, so the hydrogen peroxide produced is of higher purity. If it is used to replace anthracene The industrial-grade hydrogen peroxide produced by the quinone method can effectively reduce the purification cost of electronic-grade hydrogen peroxide. If the raw material advantages of the electrochemical method can be fully utilized and the technical disadvantages of the oxygen cathode reduction method anode or the bismuth vanadate method cathode can be solved to further reduce the production cost, then the electrochemical method is expected to replace the anthraquinone method as the mainstream of hydrogen peroxide. industrial production methods.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a kind of electrolysis method for producing high-purity hydrogen peroxide on the basis of comprehensively considering the advantages and disadvantages of the oxygen cathode reduction method and the bismuth vanadate method.

In order to achieve the above-mentioned purpose, the technical scheme adopted by the present invention to solve the above-mentioned technical problems is: a kind of electrolysis method for producing high-purity hydrogen peroxide, which adopts an oxide single wafer as the anode material of the electrolytic cell, and the carbon-based material is used as the cathode material , add neutral or alkaline electrolyte into the electrolytic cell, and after oxygen is introduced into the cathode, a bias voltage is applied to the anode and cathode of the electrolytic cell, so that the anode undergoes a two-electron water oxidation reaction to generate hydrogen peroxide (2H ₂ O → H ₂ O ₂ + 2H ⁺ + 2 e ^‒ ), and at the same time, the oxygen reduction reaction occurs at the cathode to generate hydrogen peroxide (O ₂ + 2H ⁺ + 2 e ^‒ → H ₂ O ₂ ), and the overall chemical reaction equation is O ₂ + 2H ₂ O→ 2H ₂ O ₂ .

The oxide single crystal is the same as or similar to the anode material used in the bismuth vanadate method, and can be doped bismuth vanadate single crystal {111}, {110}, {112}, {100} and other crystal planes or doped oxide Zinc single crystal {0001} plane.

The chemical composition of the doped bismuth vanadate single crystal is (Bi _1-x A _x )(V _{1- y By} )O ₄ , wherein A is a vacancy, a +1/+2/+3 valent metal cation or its Mixed component, B is a +4/+6 valent metal cation or a mixed component thereof, wherein 0≤x, y≤0.2.

The chemical composition of the doped zinc oxide single crystal is Ga:ZnO.

The +1-valent metal cations are Li, Na, K, etc.; the +2-valent metal cations are Mg, Ca, Sr, Zn, etc.; the +3-valent metal cations are Ga, In, Sc, Y or other rare earth elements, etc.; The +4-valent metal cation is Ti or Ge, etc.; the +6-valent metal cation is W, Mo, etc.

The pH range of the neutral or alkaline electrolyte is 7-13.

The oxygen is cheap oxygen with a purity of ≥ 90% prepared by an oxygen generator.

The carbon-based material is the same as or similar to the cathode material used in the oxygen cathode reduction method, and can be a graphite/carbon black/polytetrafluoroethylene composite, an oxidized or doped carbon material, or a carbon-based single-atom catalyst.

The oxide single wafer is fixed on the conductive film of the conductive glass.

The applied bias voltage is 1.8-2.5 V, and the current density during electrolysis is 0.01-0.3 A/cm ² .

After the electrolysis is completed, the electrolytes in the anode and cathode regions are collected, and the hydrogen peroxide solution is obtained after the processes including evaporation and concentration.

The beneficial effects of the invention are: compared with the bismuth vanadate method, the method replaces the proton reduction reaction that occurs at the cathode with a two-electron oxygen reduction reaction, directly converts hydrogen into hydrogen peroxide, and solves the storage and utilization of by-product hydrogen. Under the condition of 1.8-2.5 V applied bias, a single target product, hydrogen peroxide, is simultaneously generated at the anode and the cathode, which greatly increases the added value of the product; the use of two-electron oxygen reduction reaction further reduces the applied bias and improves the Electric energy utilization efficiency has important industrial application value.

Description of drawings

Fig. 1 is a schematic diagram of an electrolytic cell used in the present invention.

In the reference numerals, 111 is an anode, 112 is a cathode, 113 is a proton exchange membrane, and 121 is an applied forward bias voltage.

Detailed ways

The present invention will be further described below with reference to specific embodiments. It should be noted that the embodiments do not constitute a limitation on the protection scope of the present invention.

An electrolysis method for producing high-purity hydrogen peroxide, based on the electrolytic cell structure shown in FIG. 1 , an anode 111 and a cathode 112 are respectively arranged on the cell wall of the electrolytic cell, and in the electrolytic cell, the anode 111 and the cathode 112 are arranged between the Proton exchange membrane 113. The anode 111 uses an oxide single wafer as the anode material, and the cathode uses a carbon-based material as the cathode material. Neutral or alkaline electrolyte is added into the electrolytic cell, and after oxygen is introduced into the cathode 112, a forward bias voltage 121 is applied to the anode 111 and the cathode 112 of the electrolytic cell, so that the anode 111 undergoes a two-electron water oxidation reaction to generate Hydrogen oxide (2H ₂ O → H ₂ O ₂ + 2H ⁺ +2 e ^‒ ), and oxygen reduction reaction occurs at the cathode 112 to generate hydrogen peroxide (O ₂ + 2H ⁺ + 2 e ^‒ → H ₂ O ₂ ), the total chemical The reaction equation is O ₂ + 2H ₂ O → 2H ₂ O ₂ . Wherein, the oxide single wafer in the anode 111 is fixed on the conductive film of the conductive glass. The conductive glass is composed of a glass substrate and a conductive film attached to the glass substrate, which can be ITO glass or FTO glass. An oxygen inlet is provided on the tank wall corresponding to the cathode 112, and the oxygen inlet communicates with the carbon-based material on the cathode 112, so as to efficiently introduce the oxygen required for the reaction.

The following takes the production of 1 ton of 30% hydrogen peroxide as an example for further explanation.

The doped bismuth vanadate <111> single wafer was used as the anode of the electrolytic cell, and the commercial graphite/carbon black/polytetrafluoroethylene composite was used as the cathode of the electrolytic cell, and the effective area was 10 m ² ; the applied bias voltage was 2.5 V, unit The area current intensity is 0.3 A/cm ² ; the purity of oxygen fed into the cathode is ³ 90%, which is provided by the oxygen generator (oxygen production ³ 14 Nm ³ /h). According to the current conversion efficiency of 100% of the anode and 90% of the cathode, without considering the energy consumption of the oxygen generator, the production of the above hydrogen peroxide requires 622 kWh of electricity, which takes about 8 hours. If the power of the oxygen generator is 18 kW, the power consumption for producing the above-mentioned hydrogen peroxide is about 766 kWh.

If adopt the bismuth vanadate method to produce above-mentioned hydrogen peroxide and by-product hydrogen 200 Nm ^The electric energy that needs to consume is 1322 kilowatt hours, and the required time is about 16 hours (according to the document: the patent application number is 201610567960.5, and the patent name is "a kind of Low-cost production of high-purity hydrogen peroxide and hydrogen electrolysis method" Chinese invention patent application).

Compared with the bismuth vanadate method, in the present invention, hydrogen is directly converted into hydrogen peroxide, which solves the problem of storage and utilization of the by-product hydrogen, shortens the production time, improves the electric energy utilization efficiency, and greatly increases the added value of the product.

The above are only preferred embodiments of the present invention, and should not limit the scope of implementation of the present invention, that is, any simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the contents of the description of the invention are still applicable. It belongs to the scope covered by the patent of the present invention.

Claims (8)

1. An electrolytic process for producing high purity hydrogen peroxide, characterized by: the method comprises the steps of adopting an oxide single crystal wafer as an anode material of an electrolytic cell, adopting a carbon-based material as a cathode material, adding neutral or alkaline electrolyte into the electrolytic cell, introducing oxygen into a cathode, and applying bias voltage to the anode and the cathode of the electrolytic cell to enable the anode to generate two-electron water oxidation reaction to generate hydrogen peroxide, and simultaneously enabling the cathode to generate oxygen reduction reaction to generate hydrogen peroxide.

2. An electrolytic process for producing high purity hydrogen peroxide according to claim 1, wherein: the oxide single crystal wafer is a doped bismuth vanadate single crystal {111}, {110}, {112}, {100} crystal face or a doped zinc oxide single crystal {0001} crystal face.

3. An electrolytic process for producing high purity hydrogen peroxide according to claim 2, wherein: the carbon-based material is a graphite/carbon black/polytetrafluoroethylene compound, an oxidized or doped carbon material or a carbon-based single-atom catalyst.

4. An electrolytic process for producing high purity hydrogen peroxide in accordance with claim 1 in which: the oxygen introduced into the cathode is oxygen with the purity of 90% prepared by the oxygen generator.

5. An electrolytic process for producing high purity hydrogen peroxide in accordance with claim 1 in which: the pH value of the neutral or alkaline electrolyte is 7-13.

6. An electrolytic process for producing high purity hydrogen peroxide in accordance with claim 2 in which: the single crystal wafer of the oxide is fixed on a conductive film of conductive glass.

7. An electrolytic process for producing high purity hydrogen peroxide in accordance with claim 1 in which: the external bias voltage is 1.8-2.5V, and the current density during electrolysis is 0.01-0.3A/cm²。

8. An electrolytic process for producing high purity hydrogen peroxide according to claim 1, wherein: and collecting the electrolyte in the anode and cathode regions after the electrolysis is finished, and obtaining the hydrogen peroxide solution through evaporation and concentration treatment.

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