CN113789538A

Movatterモバイル変換

Info

Publication number: CN113789538A
Application number: CN202111345123.5A
Authority: CN
Inventors: 何頔; 李世亮; 马金星; 廖晓婷
Original assignee: Guangdong University of Technology
Current assignee: Guangdong University of Technology
Priority date: 2021-11-15
Filing date: 2021-11-15
Publication date: 2021-12-14
Anticipated expiration: 2041-11-15
Also published as: CN113789538B

Abstract

Translated fromChinese

本发明属于环境工程与能源利用领域，公开了一种带悬浮催化层的气体扩散阴极及原位产过氧化氢的电化学反应器，所述气体扩散阴极包括依次设置的扩散层、集流体基底和悬浮催化层；所述原位产过氧化氢电化学反应器包括依次叠合设置的阴极端板、上述所述气体扩散阴极、阴离子交换膜、固态电解质层、阳离子交换膜、铂阳极、阳极端板；所述气体扩散阴极和铂阳极分别通过导线与电源的负极与正极连接。本发明所述气体扩散阴极创造性的使用了悬浮催化层，有利于加快氧还原的电子转移速率、提高电化学产H₂O₂的效能；本发明反应器在引入上述气体扩散阴极的同时，进一步使用了固态电解质层，确保以更安全、更有效的方式原位产H₂O₂。

The invention belongs to the fields of environmental engineering and energy utilization, and discloses a gas diffusion cathode with a suspended catalytic layer and an electrochemical reactor for in-situ production of hydrogen peroxide. The gas diffusion cathode comprises a diffusion layer and a current collector substrate arranged in sequence. and a suspended catalytic layer; the in-situ hydrogen peroxide production electrochemical reactor includes a cathode end plate, the above-mentioned gas diffusion cathode, an anion exchange membrane, a solid electrolyte layer, a cation exchange membrane, a platinum anode, an anode an extreme plate; the gas diffusion cathode and the platinum anode are respectively connected to the negative and positive electrodes of the power supply through wires. The gas diffusion cathode of the present invention creatively uses a suspended catalyst layer, which is beneficial to accelerate the electron transfer rate of oxygen reduction and improve the efficiency of electrochemical production of H₂ O₂ ; while introducing the above gas diffusion cathode into the reactor of the present invention, it further A solid electrolyte layer is used to ensure in situ H₂ O₂ production in a safer and more efficient manner.

Description

Gas diffusion cathode with suspension catalyst layer and electrochemical reactor

Technical Field

The invention belongs to the field of environmental engineering and energy utilization, and particularly relates to a gas diffusion cathode with a suspended catalyst layer and an electrochemical reactor for in-situ production of hydrogen peroxide.

Background

Hydrogen peroxide is an important and green chemical substance and has wide application in chemical industry and environmental protection. Due to its strong oxidizing property, H₂O₂Is considered to be a promising agent for water treatment, is commonly used in advanced oxidation technology, and can also be used for disinfection of drinking water.

Currently, about 95% of commercial H₂O₂Is through H₂Hydrogenated alkylanthraquinones and their use in organic solvents with O₂The indirect anthraquinone process of oxidized hydroquinone is a multi-step process that requires a large input of energy and generates a large amount of waste. Although the anthraquinone process can produce high concentrations of H₂O₂But the concentration is far higher than the concentration required by actual water treatment, and the instability of the water treatment system brings great potential safety hazard in the transportation and storage processes. Electrochemical process for producing H₂O₂It provides an attractive approach to effectively solve the problems associated with the anthraquinone process. In addition, H synthesized by in situ electrochemical method₂O₂Can be combined with renewable energy sources for wastewater treatment in remote areas.

Electrochemical in situ synthesis of H₂O₂In the process, the high activity and selectivity of the catalyst play an important role. The metal-based catalyst has higher selectivity for electrochemical production, but considering the factors of high cost, part of materials having toxicity and the like, the carbon material has lower cost and abundant sources and has unique surface and structural characteristics, the demand for developing cathode catalysts prepared from carbon materials is increased greatly day by day, so that a carbon material gas diffusion cathode with high-efficiency mass transfer is developed,and assembled into a reactor for in-situ generation of hydrogen peroxide, using the generated H₂O₂The catalyst is added into a reaction tank of Advanced Oxidation Processes (AOPs), and has important significance for improving the efficiency of degrading organic pollutants.

Disclosure of Invention

In view of the problems in the prior art, it is an object of the present invention to provide a gas diffusion cathode with a suspended catalyst layer, which can realize high mass transfer efficiency.

Another purpose of the invention is to provide a method which has simple configuration, is beneficial to accelerating the oxygen reduction electron transfer rate and improving the electrochemical H generation₂O₂In situ hydrogen peroxide in a concentration.

In order to realize the purpose of the invention, the concrete scheme is as follows:

a gas diffusion cathode with a suspension catalyst layer comprises a diffusion layer, a current collector substrate and a suspension catalyst layer which are sequentially arranged;

the current collector substrate is one of foamed nickel, stainless steel mesh or carbon felt;

the diffusion layer is prepared from carbon black and PTFE emulsion according to a certain proportion, and is coated on one side of the current collector substrate;

the main body of the suspension catalyst layer is an organic glass plate or a polytetrafluoroethylene plate which is adjacent to the other side of the current collector substrate, a first flow channel is arranged in the suspension catalyst layer, one side of the first flow channel is the surface of the current collector substrate, a suspension prepared from a carbon material is continuously pumped into the first flow channel through a peristaltic pump, and the suspension is obtained by uniformly mixing carbon black, graphene or acetylene black with ultrapure water.

Further, the current collector substrate is foamed nickel, the porosity of the foamed nickel is 90-98%, the pore diameter is 0.2-0.6 mm, the thickness is 0.5-1.5 mm, and the surface density is 280-400 g/m²。

Further, the thickness of the suspended catalyst layer is 1.5-4.5 mm, and preferably 3 mm; the flow rate of the carbon material suspension is 5-20 ml/min, preferably 10 ml/min; the concentration of the carbon material suspension is 10-25 mg/L, and preferably 20 mg/L.

Further, the carbon material suspension is one of a carbon black suspension, a graphene suspension and an acetylene black suspension, and the particle size of the carbon material is preferably 20-50 nm.

Furthermore, in order to increase the contact area between the carbon material suspension and the current collector substrate and reduce the viscous resistance of the carbon material suspension at the turning position of the flow channel, the first flow channel is arranged as a snake-shaped flow channel.

Furthermore, the thickness of the diffusion layer is 0.3-0.6 mm.

Further:

the preparation method of the current collector substrate comprises the following steps:

taking one of foamed nickel, stainless steel mesh or carbon felt as a current collector substrate, and cleaning the current collector substrate with deionized water and ethanol for later use;

the preparation method of the diffusion layer comprises the following steps:

(1) mixing a carbon material and absolute ethyl alcohol according to a ratio of 1g to 15-20 ml, and uniformly stirring; then, adding 60% of PTFE emulsion drop by drop, mixing and stirring uniformly; during the period, the mass ratio of the carbon black to the PTFE emulsion is controlled to be 1-2: 3-7; obtaining viscous floccule;

(2) coating the viscous floccule obtained in the step (1) on a current collector to form a load capacity of 30-60 mg/cm²A diffusion layer of (a);

(3) calcining the coated current collector obtained in the step (2) for 2.5-3.5 hours at the temperature of 350 +/-20 ℃; obtaining the product;

the preparation method of the suspended catalyst layer comprises the following steps:

etching a snake-shaped flow channel on an organic glass plate or a polytetrafluoroethylene plate, uniformly mixing carbon black, graphene or acetylene black and ultrapure water to form a carbon material suspension, and controlling a peristaltic pump I to enable the carbon material suspension in the flow channel to flow.

The invention also discloses an electrochemical reactor for in-situ production of hydrogen peroxide, which comprises a cathode end plate, the gas diffusion cathode, an anion exchange membrane, a solid electrolyte layer, a cation exchange membrane, a platinum anode and an anode end plate which are sequentially overlapped; the gas diffusion cathode and the platinum anode are respectively connected with the negative electrode and the positive electrode of a power supply through leads, wherein:

an opening which is used for air to pass through and is directly contacted with the diffusion layer of the gas diffusion cathode is arranged in the center of the cathode end plate in a penetrating manner;

an anode reaction chamber communicated with the cation exchange membrane is arranged in the anode end plate, and a water inlet of the anode reaction chamber is arranged on the anode end plate;

the main body of the solid electrolyte layer is an organic glass plate or a polytetrafluoroethylene plate between an anion exchange membrane and a cation exchange membrane, the solid electrolyte layer is provided with a reaction through hole communicated with the anion exchange membrane and the cation exchange membrane and a second flow channel penetrating through the reaction through hole and the solid electrolyte layer, solid electrolyte particles are filled in the reaction through hole, and sodium sulfate solution or deionized water is continuously pumped into the second flow channel through a peristaltic pump, so that a hydrogen peroxide product in the reaction through hole is taken out.

Further, the solid electrolyte is porous solid electrolyte particles; preferably one or more of styrene-divinylbenzene copolymer, perovskite type inorganic solid electrolyte LLTO, PEO based polymer-ceramic hybrid solid electrolyte.

Furthermore, the particle size of the solid electrolyte particles is 50-400 μm.

Furthermore, two ends of the second flow channel are provided with water-permeable sieve plates, and meshes of the sieve plates are smaller than the particle size of the solid electrolyte particles, so that the solid electrolyte particles are prevented from being washed away.

Furthermore, the preferred sodium sulfate solution continuously pumped into the two-way flow channel II by the peristaltic pump can obviously improve the H yield₂O₂And (4) concentration.

Furthermore, the cathode end plate and the anode end plate are made of organic glass plates or polytetrafluoroethylene plates.

Furthermore, the thickness of the solid electrolyte layer is 0.4-0.6 cm, the reaction through hole is a square opening arranged in the center of the solid electrolyte layer, and the side length is (2-4) cm x (2-4) cm. The reasonable thickness can improve the combination rate and efficiency of the anions and the cations across the ion exchange membrane.

Further, the flow rate of the sodium sulfate solution or the deionized water is 90-2700 mu l/min.

Furthermore, in order to maintain a good sealing effect, silica gel pads are arranged between the cathode end plate and the gas diffusion cathode and between the anode end plate and the platinum anode, and the silica gel pads are open at the cathode reaction chamber and the anode reaction chamber.

Further, the size of the cathode end plate, the suspension catalyst layer, the anion exchange membrane, the solid electrolyte layer, the cation exchange membrane and the anode end plate is larger than the diffusion layer, the current collector substrate and the platinum anode of the gas diffusion cathode, and the end edge opposite positions of the cathode end plate, the suspension catalyst layer, the anion exchange membrane, the solid electrolyte layer, the cation exchange membrane and the anode end plate are provided with mounting holes for the screw to pass through, and the electrochemical reactor is fastened by the screw and the adaptive bolt sequentially passing through the cathode end plate, the suspension catalyst layer, the anion exchange membrane, the solid electrolyte layer, the cation exchange membrane and the anode end plate.

Further, according to the invention, the gas generated by the anode reaction chamber is enough to be supplied to the cathode, the air hood is arranged at the opening of the cathode end plate, the anode reaction chamber is provided with an air outlet, and the air outlet is communicated with the air hood pipeline.

The hydrogen peroxide reactor of the present invention is also suitable for supplying hydrogen peroxide in an electro-fenton system.

Compared with the prior art, the invention has the beneficial effects that:

(1) the gas diffusion cathode has a simple structure, the foamed nickel and the stainless steel mesh or the carbon felt are used as a current collector substrate, and the raw materials of the diffusion layer only relate to carbon black, PTFE emulsion and ethanol. At the same time, a suspension catalyst layer is creatively used, a serpentine flow channel is preferably introduced, so that the carbon material suspension continuously flows in the serpentine flow channel, water in the suspension is used as a reactant, and each active site of the cathode participates in the reduction reaction of oxygen, thereby being beneficial to accelerating the electron transfer rate of oxygen reduction and improving the electrochemical H production₂O₂The concentration of (c).

（2）The electrochemical reactor for in-situ hydrogen peroxide production creatively uses the solid electrolyte layer in a closed area between the solid electrolyte layer and the anion and cation exchange membranes, namely the through hole, and is mainly filled with solid electrolyte (SPE) microspheres instead of the traditional H production₂O₂Liquid electrolytes are commonly used in reactors. The solid electrolyte ensures in-situ production of H in a safer and more efficient manner due to its fast ionic conduction at room temperature, high reliability and easy processing characteristics₂O₂。

(3) The electrochemical reactor for in-situ generation of hydrogen peroxide creatively limits the thickness of the introduced solid electrolyte, enhances the conductivity of the electrolyte and improves the combination rate and efficiency of anions and cations crossing the ion exchange membrane. With Na₂SO₄The solution or deionized water is fed into the reactor at constant flow rate, and after the concentration of the solution or deionized water is properly regulated, the effective mass transfer of ions in micro channels among the solid electrolyte microspheres can be strengthened, and the HO in the closed area can be improved₂^-And H⁺Combined to form H₂O₂The efficiency of (c).

(4) The opening of the cathode end plate is provided with an air hood, the anode end plate is also provided with an air outlet, the air outlet is communicated with an air hood pipeline, the anode generates four-electron oxidation reaction of water to generate oxygen, the oxygen generated by the anode can reach the cathode side through the air hood and an air pipe, and enters the opening of the gas diffusion cathode at a certain concentration, so that the high-efficiency utilization of energy is realized.

(5) The hydrogen peroxide reactor is also suitable for an electro-Fenton system, and H does not need to be added from an external source in the electro-Fenton system₂O₂H produced by the reactor₂O₂Can be directly mixed with Fe²⁺The method is used for Fenton reaction under acidic conditions, and the organic pollutants are efficiently removed.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, serve to explain the invention and not to limit the invention.

Fig. 1 is a schematic diagram of an electrochemical in-situ hydrogen peroxide generation reactor with a suspended catalyst layer according to the present invention.

FIG. 2 is a schematic configuration diagram of a suspended catalyst layer formed by adding a suspension liquid in a serpentine flow channel.

FIG. 3 is a schematic view of a solid electrolyte layer of the reactor of the present invention.

FIG. 4 is a schematic diagram of the anode end plate structure of the reactor of the present invention.

FIG. 5 is a schematic view of the configuration of the air shroud outside the gas diffusion cathode of the present invention.

FIG. 6 shows the results of the hydrogen peroxide concentration test (applied voltage of 10V) in the reactor of the present invention under different flow rates of deionized water.

FIG. 7 shows the results of the hydrogen peroxide concentration test (deionized water flow rate of 450. mu.L/min) before and after the addition of the suspended catalyst layer in the reactor of the present invention.

Detailed Description

In order to facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of the present invention is not limited to the specific embodiments below.

Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.

Example 1

The embodiment discloses a gas diffusion cathode, and the specific structure can be seen as reference numeral 2 in fig. 1, where the gas diffusion cathode 2 includes a diffusion layer, a current collector substrate, and a suspended catalyst layer 8, which are sequentially disposed;

the current collector substrate is made of foamed nickel, the porosity of the foamed nickel is 95%, the pore diameter is 0.2-0.6 mm, the thickness is 1.0mm, and the surface density isIs 325g/m²；

The preparation method comprises the following steps:

cutting foamed nickel into square, and ultrasonically cleaning the square with deionized water and ethanol for later use.

The diffusion layer is prepared from carbon black and PTFE emulsion in proportion, the diffusion layer is coated on one side, which is close to the outside, of the current collector substrate, and the preparation method comprises the following steps:

(1) mixing carbon black particles and absolute ethyl alcohol according to the proportion of 1g to 20ml, and ultrasonically stirring uniformly; then, adding 60% of PTFE emulsion drop by drop, mixing and ultrasonically stirring uniformly; during the period, the mass ratio of the carbon black to the PTFE emulsion is controlled to be 1: 5; obtaining viscous floccule;

(2) coating the viscous floccule obtained in the step (1) on a current collector to form a load of 60mg/cm²A diffusion layer of (a);

(3) calcining the coated current collector obtained in the step (2) for 3 hours at the temperature of 350 ℃;

(4) repeating the step (2) and the step (3) for 2 times until the thickness of the diffusion layer is 0.5 mm.

The main body of the suspended catalyst layer 8 is an organic glass plate which is close to the other side of the current collector substrate, referring to fig. 2, afirst flow channel 16 which flows along the surface of the current collector substrate is arranged in the suspended catalyst layer, thefirst flow channel 16 is a snake-shaped flow channel, a carbon material suspension is continuously pumped into thefirst flow channel 16 through a peristaltic pump, the carbon material suspension is obtained by uniformly mixing carbon black and ultrapure water, and the carbon black is selected to have a particle size of about 30 nm.

In this embodiment, the thickness of the suspended catalyst layer 8 is 3 mm; the flow rate of the carbon material suspension is set to be 10 ml/min; the concentration of the carbon material suspension is 20 mg/L.

etching a snake-shaped flow channel on an organic glass plate, uniformly stirring and mixing carbon black for 12 hours to form a carbon material suspension, and controlling a peristaltic pump I to enable the carbon material suspension in the flow channel to flow.

In this embodiment, the two ends of the first flow channel are respectively a suspension liquid inlet and a suspension liquid outlet which are arranged on the suspension catalyst layer 8, a suspension liquid container filled with a carbon material suspension is arranged outside the suspension catalyst layer 8, the suspension liquid container is communicated with the suspension liquid inlet and the suspension liquid outlet of the suspension catalyst layer through a suspensionliquid conveying pipeline 12, the peristaltic pump is arranged on the suspension liquid conveying pipeline, the suspension liquid is conveyed to the first flow channel on the back of the gas diffusion cathode at a pump speed of 10ml/min under the driving of the peristaltic pump, in this embodiment, the suspension liquid inlet is arranged above the suspension liquid outlet and is subjected to the action of gravity and the positive pressure condition formed inside, after entering the suspension liquid inlet, the carbon material suspension flows through the back of the whole gas diffusion cathode according to the path set by the flow channel and then flows out through the suspension liquid outlet on the outer side, and the suspension liquid returns to the suspension liquid container through a pipeline and then enters the reactor system again through the pumping action of the peristaltic pump I. The carbon black does not participate in the oxidation-reduction reaction in the whole process, and is only used as a flowing catalyst to accelerate the efficiency of oxygen to obtain electrons.

Example 2

The embodiment discloses an electrochemical reactor for in-situ hydrogen peroxide production, as shown in fig. 1-5, the reactor comprises a cathode end plate 1-1, a silica gel pad 7, a gas diffusion cathode 2, ananion exchange membrane 3, asolid electrolyte layer 4, acation exchange membrane 5, a platinum anode 6, a silica gel pad 7 and an anode end plate 1-2 which are sequentially arranged in embodiment 1, and a movable power supply 13 is connected with two ends of the gas diffusion cathode 2 and the platinum anode 6, wherein the main bodies of the cathode end plate 1-1, the anode end plate 1-2, thesolid electrolyte layer 4 and a suspension catalyst layer 8 are all made of organic glass plates.

An opening for air to pass through is formed in the center of the cathode end plate 1-1 in a penetrating manner, ananode reaction chamber 19 communicated with thecation exchange membrane 5 is arranged in the anode end plate 1-2, a water inlet 17 and an air outlet 18 communicated with theanode reaction chamber 19 are arranged on the anode end plate 1-2, as shown in fig. 4, the anode end plate 1-2 is a schematic structural diagram of the anode end plate 1-2 in the embodiment, the water inlet 17 and the air outlet 18 share one opening of the anode end plate 1-2, an air hood (as shown in fig. 5) is arranged at the opening of the cathode end plate 1-1, and the air outlet 18 is communicated with an air hood pipeline, so that gas generated by an anode flows to the cathode for use.

Referring to fig. 3, the main body of thesolid electrolyte layer 4 is an organic glass plate between theanion exchange membrane 3 and thecation exchange membrane 5, thesolid electrolyte layer 4 is provided with a reaction throughhole 14 communicating theanion exchange membrane 3 and thecation exchange membrane 5, and asecond flow channel 15 penetrating through the reaction throughhole 14 and thesolid electrolyte layer 4, the reaction throughhole 14 is filled withsolid electrolyte particles 9, and the solid electrolyte particles are styrene-divinylbenzene copolymer microspheres with a particle size of 200 to 300 μm in this embodiment. Sodium sulfate solution or deionized water is continuously pumped into the two-way flow channel II 15 through the peristaltic pump, so that hydrogen peroxide products in the reaction throughholes 14 are taken out, a water-permeable sieve plate is arranged in the two-way flow channel 15, and the mesh size of the sieve plate is 2 micrometers.

In this embodiment, the sizes of the cathode end plate 1-1, the suspension catalyst layer 8, theanion exchange membrane 3, thesolid electrolyte layer 4, thecation exchange membrane 5 and the anode end plate 1-2 are larger than the diffusion layer, the current collector substrate and the platinum anode 6 of the gas diffusion cathode, and mounting holes for screws to pass through are arranged at the opposite positions of the end edges of the cathode end plate 1-1, the suspension catalyst layer 8, theanion exchange membrane 3, thesolid electrolyte layer 4, thecation exchange membrane 5 and the anode end plate 1-2, and the electrochemical reactor is fastened by the screws and the adaptive bolts sequentially passing through the cathode end plate 1-1, the suspension catalyst layer 8, theanion exchange membrane 3, thesolid electrolyte layer 4, thecation exchange membrane 5 and the anode end plate 1-2.

In this embodiment, the thickness of solidstate electrolyte layer 4 is 0.5cm, reaction through-hole 14 is the square, the length of side of square reaction through-hole 14 is 2.5cm, the both ends of runner two 15 are respectively for setting upinlet 10 andliquid outlet 11 on solidstate electrolyte layer 4, solidstate electrolyte layer 4 still is provided with hydrogen peroxide collection room and sodium sulfate solution or deionized water reservoir outward, hydrogen peroxide collection room communicates with each other withliquid outlet 11 through pipeline, sodium sulfate solution or deionized water storage container pass through pipeline andinlet 10 intercommunication, peristaltic pump two sets up on pipeline, and under peristaltic pump two's drive, sodium sulfate solution or deionized water pass through the pipeline and get into square reaction through-hole 14 and take out hydrogen peroxide product to hydrogen peroxide collection room.

Example 3

In this example, the hydrogen peroxide reactor described in example 2 was used for production test, and this example was carried out under a constant-pressure 10V operating condition, with the reactor current density set at 2.4 mA/cm²。

The method specifically comprises the following steps:

after air diffuses to the opening of the reactor cathode end plate 1-1, the air sequentially passes through the diffusion layer of the gas diffusion cathode 2 and the current collector substrate, and reduction reaction occurs on the suspended catalyst layer 8 formed by carbon black suspension.

0.05-0.2 mol/L sulfuric acid aqueous solution is prepared, and in the embodiment, the 0.1mol/L sulfuric acid aqueous solution is conveyed to the surface of the Pt anode 6 in the anode reaction chamber through a water inlet at the upper end of the anode end plate 1-2 to generate oxidation reaction.

HO generated by reduction of oxygen on cathode side₂^-H generated by oxidizing water at anode side⁺Respectively cross over theanion exchange membrane 3 and thecation exchange membrane 5 to reach a closed area enclosed by thesolid electrolyte layer 4 and the two ion exchange membranes, namely a reaction throughhole 14. The reaction through-holes 14 are filled withsolid electrolyte particles 9, and HO generated by oxygen reduction on the cathode side₂^-And H generated by water oxidation on the anode side⁺Recombination at this position to form H₂O₂。

The second peristaltic pump delivers deionized water at 0.9ml/min through theliquid inlet 10 to the surfaces of thesolid electrolyte particles 9 in the reaction throughholes 14, the liquid flows along the micro-channels among thesolid electrolyte particles 9, and H generated inside is taken out₂O₂Is carried to aliquid outlet 11 and is collected in a hydrogen peroxide collecting chamber.

Example 4

This embodiment is basically the same asembodiment 3, except that:

the peristaltic pump II conveys deionized water at a speed of 1.8ml/min through theliquid inlet 10 to the surfaces of thesolid electrolyte particles 9 in the reaction throughholes 14, the liquid flows along the micro-channels among thesolid electrolyte particles 9, and H generated inside the liquid flows₂O₂Is brought to and taken outAnd aliquid port 11 for collecting the hydrogen peroxide into the hydrogen peroxide collecting chamber.

Example 5

This embodiment is basically the same asembodiment 3, except that:

the peristaltic pump II conveys deionized water at 2.7ml/min through theliquid inlet 10 to the surfaces of thesolid electrolyte particles 9 in the reaction throughholes 14, the liquid flows along the micro-channels among thesolid electrolyte particles 9, and H generated inside the liquid flows₂O₂Is carried to aliquid outlet 11 and is collected in a hydrogen peroxide collecting chamber.

Detection example 3-5 production of H by an electrochemical method at a deionized water gradient flow rate of 0.9-2.7 ml/min₂O₂The concentration of (c). As shown in fig. 6, the specific results are as follows:

h when the flow rate of the deionized water is 0.9mL/min₂O₂The concentration is 0.12 g/L;

h when the flow rate of the deionized water is 1.8mL/min₂O₂The concentration is 0.10 g/L;

h when the flow rate of the deionized water is 2.7mL/min₂O₂The concentration was 0.07 g/L.

Description of the invention H₂O₂The concentration of the (D) is increased along with the reduction of the flow rate of the deionized water, and when the flow rate of the deionized water is 0.9ml/min, the H reaching 120mg/L can be synthesized in situ₂O₂。

Meanwhile, the energy consumption is calculated, and when the flow rate of the deionized water is controlled to be 2.7ml/min and 0.9ml/min, the electric energy consumed by 1 kilowatt hour correspondingly generates 52g H and 40g H₂O₂Illustrates that H can be produced with each degree of electricity consumed as the flow rate of deionized water is reduced₂O₂The amount of (c) will decrease.

Comparative example 1

This comparative example is substantially the same as example 2, except that:

in comparative example 1 a gas diffusion cathode without a suspended catalytic layer was used,

the gas diffusion cathode comprises a diffusion layer, a current collector substrate and a catalytic layer which are sequentially arranged;

the current collector substrate is made of foamed nickel, the porosity of the foamed nickel is 95%, the pore diameter is 0.2-0.6 mm, the thickness is 1.0mm,the surface density is 325g/m²；

The preparation method comprises the following steps:

(4) and (5) repeating the step (2) and the step (3) for 2 times until the thickness of the diffusion layer is 5 mm.

The preparation method of the catalyst layer comprises the following steps:

(1) mixing carbon black particles and absolute ethyl alcohol according to the proportion of 1g to 20ml, and ultrasonically stirring uniformly; then, adding 60% of PTFE emulsion drop by drop, mixing and ultrasonically stirring uniformly; during the period, the mass ratio of the carbon black to the PTFE emulsion is controlled to be 1: 2; obtaining viscous floccule, wherein the particle size of carbon black is about 30 nm;

(2) coating the viscous floccule obtained in the step (1) on a current collector to form a load of 60mg/cm²A catalytic layer of (a);

(3) calcining the coated current collector obtained in the step (2) for 3 hours at the temperature of 350 ℃; so as to obtain the fixed catalyst layer of the gas diffusion cathode.

Example 6

In this example, the hydrogen peroxide reactor described in example 2 was used for production test, and this example was carried out under a constant-pressure 10V operating condition, with the reactor current density set at 2.4 mA/cm²The flow rate of deionized water was set at 450. mu.L/min.

The method specifically comprises the following steps:

after freely diffusing to the opening of the reactor cathode end plate 1-1, the air passes through the diffusion layer of the gas diffusion cathode 2 and the current collector substrate in sequence, and is subjected to reduction reaction on the suspended catalyst layer 8 formed by carbon black suspension.

Pure water is conveyed to the surface of a Pt anode 6 in the anode reaction chamber through a water inlet at the upper end of the anode end plate 1-2 to generate oxidation reaction.

HO generated by reduction of oxygen on cathode side₂^-H generated by oxidizing water at anode side⁺Respectively strides across theanion exchange membrane 3 and thecation exchange membrane 5 to reach a closed area surrounded by thesolid electrolyte layer 4 and the two ion exchange membranes, namely a reaction through hole,solid electrolyte particles 9 are filled in the through hole, and HO generated by oxygen reduction at the cathode side₂^-And H generated by water oxidation on the anode side⁺Recombination at this position to form H₂O₂。

A peristaltic pump II conveys deionized water at 450 mu L/min through aliquid inlet 10 to the surfaces of thesolid electrolyte particles 9 in the through holes, the liquid flows along the micro-channels among thesolid electrolyte particles 9, and H generated in the liquid flows₂O₂Is carried to aliquid outlet 11 and is collected in a hydrogen peroxide collecting chamber.

Examples 7 to 9

Examples 7 to 9 are basically the same as example 6, except that:

examples 7 to 9 were carried out under operating conditions of constant pressure of 12V, 14V and 16V in this order.

Comparative examples 2 to 5

Comparative examples 2 to 5 are substantially the same as example 6, except that:

comparative examples 2-5 the reactor without the suspended catalyst layer provided in comparative example 1 was used.

Comparative examples 2 to 5 were conducted under constant pressure conditions of 10V, 12V, 14V and 16V in this order.

Referring to FIG. 7, the test results of examples 6 to 9 and comparative examples 2 to 5 are as follows:

when the voltage is 10V, the no-flow channel reactor produces H₂O₂The concentration is 0.04g/L, and the concentration with a flow passage is 0.18 g/L;

when the voltage is 12V, the no-flow channel reactor produces H₂O₂The concentration is 0.06g/L, and the concentration with a flow passage is 0.25 g/L;

when the voltage is 14V, the no-flow-channel reactor produces H₂O₂The concentration is 0.075g/L, and the concentration with a flow passage is 0.29 g/L;

when the voltage is 16V, the no-flow-channel reactor produces H₂O₂The concentration is 0.09g/L, and the concentration with a flow passage is 0.34 g/L.

Example 10

This example provides an application of the reactor described in example 2 in an electro-fenton system, specifically:

the peristaltic pump II is pumped with acidified 0.5M Na at a pump speed of 900 μ L/min₂SO₄Rhodamine B (RhB) with initial concentration of 25mg/L and 0.5M Fe²⁺The mixed solution of the components to the solid electrolyte layer. And applying voltage of 10V to two ends of the electrode, and continuously operating for 15min to obtain colorless transparent mixed solution flowing out of the liquid outlet end, which indicates that the rhodamine is completely decolorized.

Conventional electro-Fenton reactors rely on cathodic generation of H₂O₂And Fe in the reactor²⁺And the organic matter is excited to generate hydroxyl radical (. OH) under acidic condition to realize degradation and removal of the organic matter.

Using the reactor according to this example, the reactor apparatus was smaller and smaller, H, than the conventional electro-Fenton reactor₂O₂The efficiency of the oxidation reaction with the contaminants in a smaller space is increased.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.