Device for efficiently and safely preparing arsine through electro-catalysis

Abstract

The utility model discloses a device for efficiently and safely preparing arsine through electro-catalysis, which belongs to the technical field of electro-catalysis and comprises an electrolytic bath, an anode pump, an anode gas collector, a differential pressure gauge, a cathode pump, a cathode gas collector and an external power supply. The electrolytic cell comprises an anode cavity, an anode electrode, a cathode electrode and a cathode cavity, the anode cavity is of a closed structure except the bottom, a filter head is arranged at the bottom, an air outlet is formed in the upper part of the cathode cavity, the whole electrolytic cell is of a closed structure, and the anode cavity is vertically inserted into the cathode cavity in a sealing manner. The anode of the equipment can produce oxygen to achieve the purpose of purifying air, the cathode can be used for preparing efficient electronic special gas arsine, the principle is that elemental arsenic is subjected to electrochemical reduction to generate arsine, and the equipment is simple to operate, low in cost and capable of effectively avoiding the explosion danger when strong reducing gas arsine is mixed with air or oxygen during preparation. Meanwhile, arsine preparation can be efficiently carried out, and great application potential is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of electrocatalysis, and in particular relates to a device for preparing arsine by electrocatalysis in an efficient and safe manner. Background Art

[0002] Arsine plays an indispensable role in the development of information technology and energy strategies, and is a key supporting material for the development of semiconductors and high-end chip technology. Arsine is used to prepare third-generation semiconductor materials through key processes such as epitaxial growth, ion implantation, doping, and etching. Its purity determines the performance of integrated circuits and semiconductor materials, and is an indispensable key raw material for many high-tech industries. At present, the main method for preparing arsine is thermochemical method, which mainly involves reacting arsenic alloys with acids to form arsine, and purifying it through distillation and other methods to achieve a higher purity. Due to its own high toxicity and high purity requirements, the distillation cost is high and there are safety risks in the process.

[0003] The reaction process can be better controlled by electrochemical methods. Starting from the raw material of arsine, arsenic oxide or arsenic element, the purity of the raw material can be improved, and the high-purity preparation of the product arsine can be achieved, so as to reduce the cost and safety issues of the subsequent purification process. At present, there are some technologies for the electrocatalytic preparation of arsine, but the efficiency of the preparation of arsine is low, and some have safety hazards. Therefore, it is particularly important to develop an efficient, stable and safe electrocatalytic preparation of arsine. Summary of the invention

[0004] In view of the problems existing in the prior art, the object of the present invention is to provide a device for preparing arsine by electrocatalysis in an efficient and safe manner, which can effectively separate the cathode product arsine and the anode product oxygen, achieve the purpose of safe production, and efficiently prepare arsine. Through the design of the filter head, the current efficiency of the reaction can be effectively increased, and the efficiency reduction caused by the shedding of arsenic in the reaction process can be avoided. The device is simple to operate and has low cost. On the one hand, it increases the safety of the reaction process, and on the other hand, it improves the reaction current efficiency, and efficiently produces arsine. At the same time, the cathode product contains all electronic special gases that can be prepared by reduction.

[0005] A device for preparing arsine with high efficiency and safety by electrocatalysis, comprising an electrolytic cell and a differential pressure gauge, wherein the electrolytic cell comprises an anode chamber and a cathode chamber, wherein an anode exhaust port is provided at the top of the anode chamber and is connected to an anode pump and an anode gas collector in sequence through a pipeline, wherein a cathode exhaust port is provided at the top of the cathode chamber and is connected to a cathode pump and a cathode gas collector in sequence through a pipeline, wherein both ends of the differential pressure gauge are respectively connected to the pipeline on the anode exhaust port at the top of the anode chamber and the pipeline on the cathode exhaust port at the top of the cathode chamber; wherein the anode chamber is vertically sealed and inserted into the cathode chamber, a filter head is provided at the bottom of the anode chamber and the rest of the chamber except the bottom is a closed structure, an anode electrode and a cathode electrode are respectively provided in the anode chamber and the cathode chamber, and the anode electrode and the cathode electrode are respectively connected to a power source through a wire. The oxygen generated in the anode chamber enters the anode pump and the anode gas collector through the anode exhaust port at the top, and the gas generated in the cathode chamber enters the cathode pump and the cathode gas collector through the cathode exhaust port at the top.

[0006] Furthermore, the present application also defines the anode chamber as an independent enclosed space, a filter head is provided at the lower end thereof to form a "dividing line" between the anode and cathode chambers, and the materials are coarse sand, ion exchange resin, quartz stone and coral sand, etc., with quartz stone being preferred.

[0007] Furthermore, the present invention also limits the material of the differential pressure gauge to a metal stainless steel differential pressure gauge and a corrosion-resistant differential pressure gauge, with the corrosion-resistant differential pressure gauge being preferred.

[0008] Furthermore, the upper end of the anode cavity passes upward from the top of the cathode cavity, and a sealing gasket is provided between the junction of the upper end of the anode cavity and the top of the cathode cavity. The sealing gasket is silicone rubber, styrene-butadiene rubber or butadiene rubber, and silicone rubber is the best.

[0009] Furthermore, the upper end of the anode electrode passes upward from the top of the anode cavity, and a sealing gasket is provided between the upper end of the anode electrode and the top of the anode cavity. The sealing gasket is silicone rubber, styrene-butadiene rubber or butadiene rubber, and silicone rubber is the most preferred.

[0010] Furthermore, the upper end of the cathode electrode passes upward from the top of the cathode cavity, and a sealing gasket is provided between the junction of the upper end of the cathode electrode and the top of the cathode cavity. The sealing gasket is silicone rubber, styrene-butadiene rubber or butadiene rubber, and silicone rubber is the best.

[0011] Furthermore, the distance between the lower end of the anode electrode and the top of the filter head is 5-8 cm, preferably 6 cm, and the distance between the bottom of the filter head and the inner wall of the bottom of the cathode chamber is 3-10 cm, preferably 5 cm.

[0012] Furthermore, the distance between the lower end of the cathode electrode and the inner wall of the bottom of the cathode chamber is 5-10 cm, preferably 8 cm.

[0013] Furthermore, the present invention also limits the selection of anode electrode catalysts, which may be some commercial oxygen evolution catalysts, such as iridium and tantalum metals, platinum metals, etc., preferably catalysts with precious metal coatings.

[0014] Furthermore, the cathode electrode is an electrode pressed from single substance arsenic, the cathode cavity contains KOH solution electrolyte, and the electrolyte in the cathode cavity can enter the anode cavity through the filter head.

[0015] In the present invention, a traditional oxidation reaction occurs at the anode, and the product is oxygen (O2). A reduction reaction occurs at the cathode, and the product is arsine (AsH3). As a highly toxic and strongly reducing gas, it cannot be mixed and processed. Therefore, it cannot be used in reaction equipment where the cathode chamber and the anode chamber are not separated, and there is a risk of explosion. At the same time, the content of this patent is aimed at industrial scale-up. According to the degree of scale-up, the higher the degree of industrialization, the higher the possibility of mixed explosion. Therefore, it is necessary to avoid mixing of the gas products of anode and cathode electrolysis.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1) The present invention effectively avoids the mixing of the anode and cathode product gases by adopting an overall sealed structure of the electrolytic cell. The use of the filter head can, on the one hand, transmit the reaction ions, and on the other hand, effectively prevent the cathode elemental arsenic from falling off and entering the anode reaction area, which can effectively improve the current efficiency during the reaction process, maintain the stable progress of the reaction, and safely and efficiently prepare arsine;

[0018] 2) The present invention achieves efficient and safe preparation of oxygen and arsine by "isolating" the anode electrode through a filter head and the anode cavity and cathode cavity. The anode uses a noble metal coating catalyst, which can not only increase the oxygen generation rate, but also improve the reaction efficiency of the entire electrolytic cell, and indirectly improve the preparation of cathode electronic special gas arsine.

[0019] 3) The present invention provides an efficient and safe electrocatalytic device for preparing arsine. The device is simple to operate and has low cost. Compared with the previous process, on the one hand, it increases the utilization efficiency of the anode and cathode catalysts, and on the other hand, it ensures the safe production of arsine. It has the characteristics of environmental protection and low cost, realizes the integrated production of oxygen and arsine, and has great application potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the structure of a device for efficiently and safely preparing arsine by electrocatalysis in this application;

[0021] Figure 1Middle: 1. electrolytic cell, 2. anode electrode, 3. cathode electrode, 4. anode chamber, 5. cathode chamber, 6. filter head, 7. differential pressure gauge, 8. power supply, 9. anode pump, 10. cathode pump, 11. anode gas collector, 12. cathode gas collector. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0023] like Figure 1 As shown, the present invention discloses a device for preparing arsine by electrocatalysis in an efficient and safe manner, comprising an electrolytic cell 1 and a differential pressure gauge 7, wherein the electrolytic cell 1 comprises an anode chamber 4 and a cathode chamber 5, wherein an anode exhaust port is provided at the top of the anode chamber 4 and is connected to an anode pump 9 and an anode gas collector 11 in sequence through a pipeline, wherein a cathode exhaust port is provided at the top of the cathode chamber 5 and is connected to a cathode pump 10 and a cathode gas collector 12 in sequence through a pipeline, wherein both ends of the differential pressure gauge 7 are respectively connected to the pipeline on the anode exhaust port at the top of the anode chamber 4 and the pipeline on the cathode exhaust port at the top of the cathode chamber 5; wherein the anode chamber 4 is vertically sealed and inserted into the cathode chamber 5, wherein a filter head 6 is provided at the bottom of the anode chamber 4 and the rest of the parts except the bottom are closed structures, wherein an anode electrode 2 and a cathode electrode 3 are provided in the anode chamber 4 and the cathode chamber 5, respectively, and the anode electrode 2 and the cathode electrode 3 are respectively connected to a power supply 8 through a wire. The oxygen generated in the anode chamber enters the anode pump and the anode gas collector through the anode exhaust port at the top, and the gas generated in the cathode chamber enters the cathode pump and the cathode gas collector through the cathode exhaust port at the top.

[0024] To further illustrate, the anode chamber of the present invention belongs to an independent enclosed space, and a filter head is provided at its lower end to form a "dividing line" of the cathode and cathode chambers. The materials are coarse sand, ion exchange resin, quartz and coral sand, etc., preferably quartz. The pressure gauge material is a metal stainless steel pressure gauge and a corrosion-resistant pressure gauge, and a corrosion-resistant pressure gauge is preferably used. A sealing gasket is provided between the anode chamber and the cathode chamber, the anode chamber and the anode electrode, and the cathode chamber and the cathode electrode. The sealing gasket is silicone rubber, styrene-butadiene rubber or butadiene rubber, and the best is silicone rubber. To ensure the complete isolation of the cathode and cathode chambers, it is also provided that there is a certain distance between the anode electrode and the filter head, and the distance can be 5-8cm, preferably 6cm, and the distance between the filter head and the bottom of the cathode chamber is 3-10cm, preferably 5cm, to avoid the generation of cathode single substance and cause the filter head to be blocked, and the distance between the cathode electrode and the bottom of the cathode is 5-10cm, preferably 8cm, to further enhance the stability of the cathode electrode during the reaction, and to avoid the cathode mud from hindering the contact between the electrolyte and the cathode and reducing the reaction efficiency. In order to achieve the functionalization of the electrolytic cell and improve the reaction efficiency, the anode electrode catalyst selects some commercial excellent oxygen evolution catalysts, such as iridium tantalum metals, platinum metals, etc., and catalysts with precious metal coatings are preferred.

[0025] In order to achieve safe production of arsine, the present invention provides a pressure differential gauge between the cathode and anode of the device to avoid safety problems caused by sudden changes in pressure in the cathode or anode chamber during the reaction. Pressure balance in the cathode and anode chambers is achieved by adjusting the cathode and anode pumps.

[0026] Example 1: A device for efficiently and safely preparing arsenic by electrocatalysis

[0027] The anode chamber of the device adopts a polytetrafluoroethylene (PTFE) cylinder with a diameter of 4 cm, and a quartz filter is provided at the lower end. On the one hand, it can allow the electrolyte to enter the anode chamber from the cathode chamber (ion transmission), and on the other hand, it prevents dangerous accidents caused by the mixing of the cathode and cathode gases, and at the same time avoids the cathode mud generated in the cathode chamber from entering the anode chamber and reducing the reaction efficiency. The oxygen generated by the anode exhaust port is provided above the anode chamber and can be collected from here. The anode electrode is an electrode coated with a platinum metal catalyst layer. The periphery of the anode cavity and the cathode cavity are sealed with a silicone rubber pad to prevent gas leakage in the cathode cavity. The distance between the bottom of the anode electrode and the filter head is 6 cm, and the distance between the filter head and the bottom of the cathode cavity is 5 cm. The cathode electrode is an electrode pressed by arsenic. The lower end of the electrode is 8 cm away from the bottom of the cathode cavity. The cathode electrode and the cathode cavity are sealed with silicone rubber. The upper end of the cathode cavity is provided with a cathode exhaust port. A differential pressure gauge is provided above the cathode cavity and the anode cavity to avoid the safety hazards of pressure imbalance or excessive pressure in the closed anode and cathode cavities. The pressure is adjusted by the anode pump and the cathode pump, and further collected by the anode gas collector and the cathode gas collector. In the reaction, the anode electrode is a titanium material coated with platinum, the cathode is an electrode pressed by arsenic, the electrolyte is a 0.1M KOH solution, and the reaction adopts a constant current: xA (x=1, 2, 3...).

[0028] The specifications of the anode electrode in Example 1 are a rectangular titanium sheet with a length of 27 cm, a width of 3 cm, and a thickness of 0.5 cm, and the metal Pt loading is 1 mg / cm 2 The cathode is a cylindrical arsenic element with a length of 27 cm and a diameter of 2.7 cm.

[0029] The reaction conditions were changed for testing, and the results are shown in Table 1.

[0030] Table 1. Oxygen / Arsine production at different currents

[0031]

[0032] The results in Table 1 show that the present invention has excellent arsine production capacity and the equipment has good application prospects.

[0033] Example 2: A device for efficiently and safely preparing arsenic by electrocatalysis

[0034] The anode chamber of the device adopts a polytetrafluoroethylene (PTFE) cylinder with a diameter of 4 cm, and a quartz filter is provided at the lower end. On the one hand, it can allow the electrolyte to enter the anode chamber from the cathode chamber (ion transmission), and on the other hand, it prevents dangerous accidents caused by the mixing of the cathode and cathode gases, and at the same time avoids the cathode mud generated in the cathode chamber from entering the anode chamber and reducing the reaction efficiency. The oxygen generated by the anode exhaust port is provided above the anode chamber and can be collected from here. The anode electrode is an electrode coated with a platinum metal catalyst layer. The periphery of the anode cavity and the cathode cavity are sealed with a silicone rubber pad to prevent gas leakage in the cathode cavity. The distance between the bottom of the anode electrode and the filter head is 6 cm, and the distance between the filter head and the bottom of the cathode cavity is 5 cm. The cathode electrode is an electrode pressed by arsenic. The lower end of the electrode is 8 cm away from the bottom of the cathode cavity. It is sealed with silicone rubber. The upper end of the cathode cavity is provided with a cathode exhaust port. A differential pressure gauge is provided above the cathode cavity and the anode cavity to avoid the safety hazards of pressure imbalance or excessive pressure in the closed anode and cathode cavities. The pressure is adjusted by the anode pump and the cathode pump, and further collected by the anode gas collector and the cathode gas collector. In the reaction, the anode electrode is a titanium material coated with platinum, the cathode is an electrode pressed by arsenic, the reaction adopts a constant current: 3A, and the electrolyte is y M KOH solution (y = 0.1, 0.2, 0.3...).

[0035] The anode electrode and the cathode in Example 2 are the same as those in Example 1.

[0036] The reaction conditions were changed for testing, and the results are shown in Table 2.

[0037] Table 2. Oxygen / arsine production at different potassium hydroxide concentrations

[0038]

[0039] The results in Table 2 show that the present invention improves the yield of arsine by adjusting the concentration of the electrolyte, but too high a concentration will reduce the efficiency. The theoretical volume ratio of oxygen produced by the reaction to arsine is 3:4. From the data in the table, it is found that the higher the concentration of the electrolyte, the lower the relative yield of arsine. The reason is that in this reaction, hydrogen is a by-product of the cathode reaction. A high concentration of electrolyte will increase the precipitation of hydrogen, which is not conducive to the reaction.

[0040] Example 3: A device for efficiently and safely preparing arsenic by electrocatalysis

[0041] The anode chamber of the device adopts a polytetrafluoroethylene (PTFE) cylinder with a diameter of 4 cm, and a quartz filter is provided at the lower end. On the one hand, it can allow the electrolyte to enter the anode chamber from the cathode chamber (ion transmission), and on the other hand, it prevents dangerous accidents caused by the mixing of the cathode and cathode gases, and at the same time avoids the cathode mud generated in the cathode chamber from entering the anode chamber and reducing the reaction efficiency. The oxygen generated by the anode exhaust port is provided above the anode chamber and can be collected from here. The anode electrode is an electrode plated with a platinum metal catalyst layer, the periphery of the anode cavity and the cathode cavity are sealed by a silicone rubber pad to prevent gas leakage in the cathode cavity, the distance between the bottom of the anode electrode and the filter head is 6 cm, and the distance between the filter head and the bottom of the cathode cavity is 5 cm. The cathode electrode is an electrode pressed by arsenic element, and a certain distance of 8 cm is left between the lower end of the electrode and the bottom of the cathode cavity. It is sealed with silicone rubber with the cathode cavity, and a cathode exhaust port is provided at the upper end of the cathode cavity. A differential pressure gauge is provided above the cathode cavity and the anode cavity to avoid the safety hazards of pressure imbalance or excessive pressure in the closed anode and cathode cavities. The pressure is adjusted by the anode pump and the cathode pump, and further collected by the anode gas collector and the cathode gas collector. In the modified reaction, the cathode is an electrode pressed by elemental arsenic, the reaction adopts a constant current: 3A, and the electrolyte is a 0.2M KOH solution. The cathode in Example 3 is the same as that in Example 1.

[0042] The anode electrode material conditions were changed for testing, and the results are shown in Table 3.

[0043] Table 3. Oxygen / Arsine production at different anodes

[0044]

[0045] In Table 3, the specifications of the anode electrode are a rectangular structure with a length of 27 cm, a width of 3 cm, and a thickness of 0.5 cm. The loading of the iridium dioxide coating and the platinum coating is 1 mg / cm 2 .

[0046] The results in Table 3 show that the platinum-coated titanium material used in the present invention has the best catalytic effect as a catalyst anode material. The main reason for the performance difference is that different anode catalysts have different catalytic effects, which in turn affects the electron transfer of the entire reaction. Highly active anode catalysts accelerate the electron transfer rate, thereby accelerating the reaction rate of the cathode and improving the cathode's ability to produce arsine.

[0047] Comparative Example 1: Testing of a device for preparing arsine in a conventional manner

[0048] The comparative example was tested using a conventional H-Cell electrolytic cell, and the same anode and cathode materials as in the example were selected for testing, i.e., the anode specification was 27 cm long, 3 cm wide, and 0.5 cm thick, and the cathode material was arsenic element with a length of 27 cm and a diameter of 2.7 cm. The reaction was carried out using a constant current of 3 A, and the electrolyte was a 0.2 M KOH solution.

[0049] The anode electrode material conditions were changed for testing, and the results are shown in Table 4.

[0050] Table 4. Oxygen / Arsane production at different anodes

[0051]

[0052] The results in Table 4 show that when arsine is prepared in the traditional H-Cell electrolytic cell, the titanium material with platinum coating has the best catalytic effect as the catalyst anode material, and the results are consistent with those in Table 3. At the same time, it can be found that the content of arsine produced within 20 minutes is similar. As the reaction time increases, the arsine produced within 60 minutes is significantly reduced. The experimental phenomenon also shows that a large amount of arsenic is produced at the cathode tank, and loose and porous arsenic appears on the electrode surface. The current density is also gradually decreasing. The reason is that the arsenic attached to the electrode surface produced during the reaction hinders the electron transfer in the reaction process, reduces the efficiency of the reaction, and causes the yield of arsine to gradually decrease. Therefore, the removal of "cathode mud" is the key to ensuring the stable reaction and the continuous production of arsine during the reaction.

[0053] The contents described in this specification are merely an enumeration of implementation forms of the inventive concept, and the protection scope of the present invention should not be regarded as being limited to the specific forms described in the embodiments.

Claims

1. An efficient and safe electrocatalytic device for preparing arsine, characterized by: The electrolytic cell comprises an anode chamber (4) and a cathode chamber (5). The top of the anode chamber (4) is provided with an anode exhaust port and is connected to an anode pump (9) and an anode gas collector (11) in sequence through a pipeline. The top of the cathode chamber (5) is provided with a cathode exhaust port and is connected to a cathode pump (10) and a cathode gas collector (12) in sequence through a pipeline. The two ends of the differential pressure gauge (7) are respectively connected to the pipeline on the anode exhaust port at the top of the anode chamber (4) and the pipeline on the cathode exhaust port at the top of the cathode chamber (5). The anode chamber (4) is vertically sealed and inserted into the cathode chamber (5). A filter head (6) is provided at the bottom of the anode chamber (4) and the rest of the anode chamber (4) is a closed structure. Anode electrodes (2) and cathode electrodes (3) are respectively provided in the anode chamber (4) and the cathode chamber (5). The anode electrodes (2) and the cathode electrodes (3) are respectively connected to a power source (8) through a wire.

2. The device for preparing arsine by electrocatalysis efficiently and safely according to claim 1, characterized in that: The material of the filter head (6) is coarse sand, ion exchange resin, quartz stone or coral sand.

3. The device for preparing arsine by electrocatalysis efficiently and safely according to claim 1, characterized in that: The upper end of the anode cavity (4) passes upward from the top of the cathode cavity (5), and a sealing gasket is provided between the junction of the upper end of the anode cavity (4) and the top of the cathode cavity (5), and the sealing gasket is made of silicone rubber, styrene-butadiene rubber or butadiene rubber.

4. The device for preparing arsine by electrocatalysis efficiently and safely according to claim 1, characterized in that: The upper end of the anode electrode (2) passes upward from the top of the anode cavity (4), and a sealing gasket is provided between the upper end of the anode electrode (2) and the top of the anode cavity (4), and the sealing gasket is made of silicone rubber, styrene-butadiene rubber or butadiene rubber.

5. The device for preparing arsine by electrocatalysis efficiently and safely according to claim 1, characterized in that: The upper end of the cathode electrode (3) passes upward from the top of the cathode cavity (5), and a sealing gasket is provided between the junction of the upper end of the cathode electrode (3) and the top of the cathode cavity (5), and the sealing gasket is made of silicone rubber, styrene-butadiene rubber or butadiene rubber.

6. The device for preparing arsine by electrocatalysis efficiently and safely according to claim 1, characterized in that: The distance between the lower end of the anode electrode (2) and the top of the filter head (6) is 5-8 cm, and the distance between the bottom of the filter head (6) and the bottom inner wall of the cathode chamber (5) is 3-10 cm.

7. The device for preparing arsine by electrocatalysis efficiently and safely according to claim 6, characterized in that: The distance between the lower end of the anode electrode (2) and the top of the filter head (6) is 6 cm, and the distance between the bottom of the filter head (6) and the bottom inner wall of the cathode chamber (5) is 5 cm.

8. The device for preparing arsine by electrocatalysis efficiently and safely according to claim 1, characterized in that: The distance between the lower end of the cathode electrode (3) and the bottom inner wall of the cathode chamber (5) is 5-10 cm.

9. The device for preparing arsine by electrocatalysis efficiently and safely according to claim 8, characterized in that: The distance between the lower end of the cathode electrode (3) and the bottom inner wall of the cathode chamber (5) is 8 cm.

10. The device for preparing arsine by electrocatalysis efficiently and safely according to claim 1, characterized in that: The cathode electrode (3) is an electrode pressed from elemental arsenic. The cathode cavity (5) contains a KOH solution electrolyte. The electrolyte in the cathode cavity (5) can enter the anode cavity (4) through a filter head (6).

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