Electrode catalyst manufacturing system and manufacturing method

Abstract

The present invention provides an electrode-catalyst manufacturing system and manufacturing method that are capable of eliminating the scraping of an electrode-catalyst precursor that is performed by a worker and of reducing the washing time for the electrode-catalyst precursor. An electrode-catalyst manufacturing system 10 has an electrode-catalyst precursor manufacturing device 12, a washing device 13, and a drying device 14. The washing device 13 includes means that execute, after execution of a plate closing step S21 and a press fitting step S22, a normal washing step S23 for supplying washing water 43 from a feed solution supply pipe 114 to a filter chamber 112 to make the washing water 43 pass through a cake 40 containing an electrode-catalyst precursor, and then discharging the washing water 43 from filtrate discharge ports 115, 115', and a reverse washing step S24 for supplying the washing water 43 from the filtrate discharge port 115 to the filter chamber 112 to make the washing water 43 pass through the cake 40 containing the electrode-catalyst precursor, and then discharging the washing water 43 from the filtrate discharge port 115', which is different from the filtrate discharge port 115 from which the washing water 43 is supplied, and that further execute a plate opening step S25 and a cake peeling step S26. The washing device 13 is configured to adjust the thickness of the cake, which contains the electrode-catalyst precursor, during the press fitting step S22, so as to be within a range experimentally set in advance.

Description

[Technical field]

[0001] The present invention relates to a system and method for producing an electrode catalyst. [Background technology]

[0002] So-called solid polymer electrolyte fuel cells (hereinafter referred to as "PEFC" as necessary) have an operating temperature of about room temperature to 80°C. In addition, PEFCs can be made lightweight because inexpensive general-purpose plastics can be used for the components that make up the fuel cell body. Furthermore, PEFCs allow the solid polymer electrolyte membrane to be made thin, which reduces electrical resistance and makes it relatively easy to reduce power generation losses. As such, PEFCs have many advantages, making them suitable for use in fuel cell vehicles, home cogeneration systems, and the like.

[0003] As an electrode catalyst for PEFC, for example, an electrode catalyst in which platinum (Pt) or a platinum (Pt) alloy, which is an electrode catalyst component, is supported on a carbon carrier, is known. When such an electrode catalyst is used as an electrode catalyst for a fuel cell, if the electrode catalyst contains a large amount of impurities derived from the raw materials or impurities mixed in from the manufacturing equipment, sufficient catalytic activity cannot be obtained, or corrosion of the catalyst layer occurs, shortening the life of the fuel cell. For this reason, it is preferable to keep the impurity content of the electrode catalyst low. Here, examples of impurities include chemical species belonging to halogens (ions and their salts, etc.), organic substances (organic acids, their salts, condensates of organic acids), etc.

[0004] For example, in order to keep the halogen content, especially the chlorine content, of the electrode catalyst low, a process of removing chlorine may be carried out after the production of the electrode catalyst precursor, which is the raw material of the electrode catalyst. For example, Patent Document 1 discloses that a first catalyst metal precursor mixture and a carbon-based support mixture are mixed with a second catalyst metal precursor solution, pH adjustment, heating and cooling processes are repeated, and the resulting catalyst is washed 3 to 4 times with a centrifuge and dried with a freeze dryer. In addition, Patent Documents 2 and 3 disclose a method of suspending titanium dioxide in water and separating chlorine that has migrated to the liquid phase from the system by a filter press as a wet dechlorination method for ultrafine titanium dioxide that can be used as a catalyst for fuel cells. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2007-214130 A [Patent Document 2] JP 2006-265094 A [Patent Document 3] JP 2011-57552 A Summary of the Invention [Problem to be solved by the invention]

[0006] When an electrode catalyst precursor is washed using a centrifuge as in Patent Document 1, the electrode catalyst precursor adheres to the inner wall of the chamber of the centrifuge due to centrifugal force, and an operator must manually scrape off the adhered electrode catalyst.

[0007] In addition, for example, in order to sufficiently remove the chlorine components contained in the electrode catalyst precursor, washing with water and filtration must be repeated, and for example, it may take at least 2 to 4 days to wash and filter 10 to 50 kg of catalyst using one centrifuge. Thus, washing with a centrifuge has the problem of being time-consuming and inefficient.

[0008] Furthermore, Patent Documents 2 and 3 use a filter press for dechlorinating a fuel cell catalyst, but do not provide any specific description of the specific configuration or process of the filter press device or the conditions for the cleaning and filtration processes.

[0009] The present invention has been made in consideration of the above circumstances, and provides a system and method for manufacturing an electrode catalyst that can significantly reduce the effort and time required to manufacture an electrode catalyst by eliminating the need for workers to scrape off the electrode catalyst precursor and shortening the time required to wash the electrode catalyst precursor. [Means for solving the problem]

[0010] In order to solve such problems, the present invention provides: an electrode catalyst precursor manufacturing apparatus for manufacturing an electrode catalyst precursor, which is a raw material for an electrode catalyst including a conductive support and catalyst particles supported on the conductive support; a cleaning device for cleaning the electrode catalyst precursor by a filter press; a drying device that dries the electrode catalyst precursor after being washed by the washing device, The cleaning device includes: a closing step of fastening the filter plate to form a filter chamber; a pressure-injection step of injecting a liquid containing the electrode catalyst precursor from a raw liquid supply pipe into the filtration chamber under pressure, filtering the liquid, and discharging the filtrate from a filtrate discharge port; a forward washing step of supplying washing water from the raw solution supply pipe to the filtration chamber, causing the washing water to pass through a cake containing the electrode catalyst precursor, and then discharging the filtrate from the filtrate discharge port; a backwashing step of supplying washing water from the filtrate discharge port to the filtration chamber, passing the washing water through the cake containing the electrode catalyst precursor, and then discharging the washing water from a filtrate discharge port different from the filtrate discharge port through which the washing water is supplied; a plate opening step of opening the filter plate forming the filter chamber; a cake peeling step of lowering a filter cloth to peel off and drop the cake containing the electrode catalyst precursor, In the pressing step, the cake is formed to have a thickness within a range that is experimentally determined in advance, taking into consideration the cleaning degree and cleaning time required for the electrode catalyst precursor to be used. A system for manufacturing an electrode catalyst is provided.

[0011] In the electrode catalyst manufacturing system, when the conductive support is conductive carbon, the cake containing the electrode catalyst precursor during the pressing step may have a thickness of 5 to 10 mm.

[0012] The electrode catalyst manufacturing system may further include a means for causing the washing device to carry out a filter cloth washing step of washing the filter cloth with washing water after the cake peeling step.

[0013] In the electrode catalyst manufacturing system, the cleaning time of the reverse cleaning step may be approximately the same as the cleaning time of the forward cleaning step.

[0014] The present invention also provides a method for producing a method for manufacturing a semiconductor device comprising the steps of: an electrode catalyst precursor manufacturing step of manufacturing an electrode catalyst precursor, which is a raw material of an electrode catalyst including a conductive support and catalyst particles supported on the conductive support; a washing step of washing the electrode catalyst precursor by a filter press; a drying step of drying the electrode catalyst precursor after washing in the washing step, The washing step comprises: a closing step of fastening the filter plate to form a filter chamber; a pressure-injection step of injecting a liquid containing the electrode catalyst precursor from a raw liquid supply pipe into the filtration chamber under pressure, filtering the liquid, and discharging the filtrate from a filtrate discharge port; a forward washing step of supplying washing water from the raw solution supply pipe to the filtration chamber, causing the washing water to pass through a cake containing the electrode catalyst precursor, and then discharging the filtrate from the filtrate discharge port; a backwashing step of supplying washing water from the filtrate discharge port to the filtration chamber, passing the washing water through the cake containing the electrode catalyst precursor, and then discharging the washing water from a filtrate discharge port different from the filtrate discharge port through which the washing water is supplied; a plate opening step of opening the filter plate forming the filter chamber; and a cake peeling step of lowering a filter cloth to peel off and drop the cake containing the electrode catalyst precursor, In the pressing step, the cake is formed to have a thickness within a range that is experimentally determined in advance, taking into consideration the cleaning degree and cleaning time required for the electrode catalyst precursor to be used. A method for producing an electrode catalyst is provided.

[0015] In the method for producing an electrode catalyst, when the conductive support is conductive carbon, the cake containing the electrode catalyst precursor during the pressing step may have a thickness of 5 to 10 mm.

[0016] In the method for producing an electrode catalyst, the washing step may further include a filter cloth washing step of washing the filter cloth with washing water after the cake peeling step.

[0017] In the method for producing an electrode catalyst, the cleaning time of the reverse cleaning step may be approximately the same as the cleaning time of the forward cleaning step. Effect of the Invention

[0018] According to the electrode catalyst manufacturing system and manufacturing method of the present invention, the labor and time required to manufacture an electrode catalyst having a low halogen content, particularly a low chlorine content, can be significantly reduced by eliminating the need for workers to scrape off the electrode catalyst precursor and shortening the time required to wash the electrode catalyst precursor. [Brief description of the drawings]

[0019] [Figure 1] 1 is a block diagram showing a preferred embodiment of a system for producing an electrode catalyst according to the present invention. [Diagram 2]1 is a side view showing a preferred embodiment of a cleaning device in a production system and a production method for an electrode catalyst of the present invention. [Diagram 3] 1 is a perspective view showing a preferred embodiment of an operating state of a dehydration device in a plate closing step of a production system and a production method for an electrode catalyst according to the present invention. FIG. [Figure 4] 1 is a perspective view showing a preferred embodiment of an operating state of a dehydration device in a pressing step of a production system and a production method for an electrode catalyst of the present invention. FIG. [Diagram 5] 1 is a perspective view showing a preferred embodiment of an operating state of a dehydration device in a normal washing step of a production system and a production method for an electrode catalyst of the present invention. FIG. [Figure 6] 1 is a perspective view showing a preferred embodiment of an operating state of a dehydration device in a backwashing step of a production system and a production method for an electrode catalyst of the present invention. FIG. [Figure 7] 1 is a perspective view showing a preferred embodiment of an operating state of a dehydration device in a plate opening step of a production system and a production method for an electrode catalyst according to the present invention. FIG. [Figure 8] FIG. 2 is a perspective view showing a preferred embodiment of an operating state of a dewatering device in a cake peeling step of the electrode catalyst manufacturing system and manufacturing method of the present invention. [Figure 9] 1 is a perspective view showing a preferred embodiment of an operating state of a dehydrator in a filter cloth washing step of a production system and production method for an electrode catalyst of the present invention. FIG. [Figure 10] 1 is a perspective view showing a preferred embodiment of an operating state of a dehydration device in a squeezing step of a production system and a production method for an electrode catalyst of the present invention. FIG. [Figure 11] 1 is a schematic cross-sectional view showing an example of the structure of an electrode catalyst (core-shell catalyst) that can be produced by the electrode catalyst production system and production method of the present invention. FIG. [Figure 12] FIG. 2 is a schematic cross-sectional view showing another example of the structure of an electrode catalyst (core-shell catalyst) that can be produced by the electrode catalyst production system and production method of the present invention. [Figure 13]FIG. 2 is a schematic cross-sectional view showing another example of the structure of an electrode catalyst (core-shell catalyst) that can be produced by the electrode catalyst production system and production method of the present invention. [Figure 14] FIG. 2 is a schematic cross-sectional view showing another example of the structure of an electrode catalyst (core-shell catalyst) that can be produced by the electrode catalyst production system and production method of the present invention. [Figure 15] FIG. 1 is a flow chart showing a preferred embodiment of the flow of a method for producing an electrode catalyst of the present invention. [Figure 16] FIG. 2 is a flow chart showing a preferred embodiment of the flow of a washing step in the method for producing an electrode catalyst of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, preferred embodiments of the electrode catalyst manufacturing system and manufacturing method of the present invention will be described with reference to the drawings.

[0021] <Electrode catalyst manufacturing system> 1 is a block diagram showing an outline of an electrode catalyst manufacturing system 10 according to this embodiment. The electrode catalyst manufacturing system 10 includes an electrode catalyst precursor manufacturing apparatus 12 that manufactures an electrode catalyst precursor, which is a raw material for an electrode catalyst 1 (see FIG. 11), a washing apparatus 13 that washes the electrode catalyst precursor with a filter press, and a drying apparatus 14 that dries an electrode catalyst precursor 41 (see FIG. 15) after washing by the washing apparatus 13.

[0022] (Electrode catalyst precursor production equipment) The electrode catalyst precursor manufacturing apparatus 12 manufactures an electrode catalyst precursor, which is a raw material for the electrode catalyst 1. The electrode catalyst precursor manufacturing apparatus 12 includes a reaction process execution means 21 that executes a reaction process for manufacturing an electrode catalyst precursor. In the reaction process, an electrode catalyst precursor, which is a raw material for the electrode catalyst 1, is manufactured by supporting the catalyst components (core part 4, shell part 5) of the electrode catalyst 1 on the support 2 (see FIG. 11). The manufacturing method of the electrode catalyst precursor is not particularly limited as long as it is a method that can support the catalyst components of the electrode catalyst 1 on the support 2. For example, there can be mentioned an impregnation method in which a solution containing the catalyst components of the electrode catalyst 1 is brought into contact with the support 2 to impregnate the support 2 with the catalyst components, a liquid phase reduction method in which a reducing agent is added to a solution containing the catalyst components of the electrode catalyst 1, an electrochemical deposition method such as an underpotential deposition (UPD) method, a chemical reduction method, a reduction deposition method using adsorbed hydrogen, a surface leaching method of an alloy catalyst, a displacement plating method, a sputtering method, a vacuum deposition method, or the like.

[0023] (Cleaning Equipment) The washing device 13 uses a filter press to wash the electrode catalyst precursor produced in the electrode precursor production device 12. In the washing device 13, filtration and dehydration are also performed in addition to washing the electrode catalyst precursor.

[0024] FIG. 2 shows an example of a cleaning device 13 that performs a filter press. In the cleaning device 13 shown in the figure, a plurality of dehydration devices 104 are arranged in parallel in the horizontal direction on a guide rail 103 that is bridged between a front frame 101 and a rear frame 102. These dehydration devices 104 are supported so that they can move horizontally on the guide rail 103. For example, an electric cylinder 105 is supported on the rear frame 102, and the dehydration devices 104 are tightened by a pressing member 106 that reciprocates by the driving force of the electric cylinder 105. Such a cleaning device 13 for a filter press has been publicly known, and for example, one described in Japanese Patent No. 5950207 is known. In particular, the dehydration device 104 is known, for example, one described in Japanese Patent No. 5327000.

[0025] The outline of the cleaning flow using a filter press will be explained (see Figs. 3 to 10). First, the raw liquid 30 is supplied to the filter chamber 112 between the closed filter plates 111, 111', whereupon the raw liquid 30 passes through the filter cloth 113 and is filtered, and the filtrate 42 is discharged to the outside. The solid matter captured by the filter cloth 113 is dehydrated while forming a cake layer. After the dehydration is completed, the electric cylinder 105 is contracted to simultaneously open the multiple filter plates 111, 111', and at the same time, the filter cloth 113 is moved downward to discharge the dehydrated cake 40.

[0026] As shown in the block diagram of Fig. 1, the cleaning device 13 includes a plate closing step executing means 31, a pressing step executing means 32, a forward cleaning step executing means 33, a reverse cleaning step executing means 34, a plate opening step executing means 35, a cake removing step executing means 36, and a filter cloth cleaning step executing means 37, which are means for respectively executing a plate closing step, a pressing step, a forward cleaning step, a reverse cleaning step executing means 34, a plate opening step executing means 35, a cake removing step executing means 36, and a filter cloth cleaning step executing means 37. The configuration of each step S21 to S27 shown in the flow diagram of the manufacturing method of the electrode catalyst 1 in Fig. 16 described later will be described below.

[0027] [Closing process] The plate closing step S21 is a step of clamping the filter plates 111, 111' to form the filter chamber 112, and is executed by the plate closing step executing means 31. Fig. 3 is a diagram of one dewatering device 104 in the cleaning device 13 of Fig. 2, showing a preferred embodiment of the operating state in the plate closing step S21. The plate closing step executing means 31 drives the electric cylinder 105 to move the pressing member 106 toward the front frame 101, thereby bringing the two filter plates 111, 111' of the dewatering device 104 closer to each other and clamping them together to form the filter chamber 112.

[0028] [Press-fitting process] The press-in step S22 is a step of pressurizing the liquid (raw liquid) 30 containing the electrode catalyst precursor from the raw liquid supply pipe 114 into the filter chamber 112 to filter it, and discharging the filtrate 42 from the filtrate discharge ports 115, 115', and is executed by the press-in step execution means 32. FIG. 4 is a diagram of one dehydrator 104 extracted from the cleaning device 13 of FIG. 2, and shows a preferred embodiment of the operating state in the press-in step S22. When the press-in step execution means 32 pressurizes the liquid 30 containing the electrode catalyst precursor from the raw liquid supply pipe 114 into the filter chamber 112, the moisture in the liquid 30 containing the electrode catalyst precursor seeps into the filter bed 116 through the filter cloth 113 and is discharged to the outside from the filtrate discharge ports 115, 115'. As a result, the liquid 30 containing the electrode catalyst precursor pressed into the filter chamber 112 is filtered. That is, the solid components in the electrode catalyst precursor-containing liquid 30 remain in the filtration chamber 112 as a cake 40 containing the electrode catalyst precursor, and the water in the electrode catalyst precursor-containing liquid 30 is discharged to the outside as a filtrate 42.

[0029] In addition, in this pressing step S22, the cake 40 containing the electrode catalyst precursor is formed to have a thickness within a range determined experimentally in advance. The thickness of the cake 40 is determined experimentally in advance, taking into consideration the cleaning degree and cleaning time required for the electrode catalyst precursor to be used.

[0030] Here, when the electrode catalyst used uses conductive carbon as a carrier, the thickness T of the cake 40 during the pressing step S22 is preferably adjusted to 5 to 10 mm. When the thickness T of the cake 40 is 10 mm or less, a sufficient cleaning effect can be obtained relatively easily by adjusting the cleaning time in the forward cleaning step and / or reverse cleaning step described below. When the thickness T of the cake 40 exceeds 10 mm, there is a strong tendency that a sufficient cleaning effect cannot be obtained even if the cleaning time in the forward cleaning step and / or reverse cleaning step described below is extended.

[0031] Furthermore, when the thickness T of the cake 40 is 5 mm or more, cracks are less likely to form in the cake, and there is a greater tendency to prevent the formation of a path through which the wash water flows from the upstream surface of the cake to the downstream surface of the cake without passing through the cake.

[0032] [Main cleaning process] The forward washing step S23 is a step of supplying the washing water 43 from the raw liquid supply pipe 114 to the filtration chamber 112, passing the washing water 43 through the cake 40 containing the electrode catalyst precursor, and discharging the washing water 43 from the filtrate discharge ports 115, 115', and is executed by the forward washing step execution means 33. FIG. 5 is a diagram of one dehydrator 104 extracted from the washing device 13 of FIG. 2, and shows a preferred embodiment of the operating state in the forward washing step S23. The forward washing step execution means 33 causes the washing water 43 to flow from the raw liquid supply pipe 114 toward the filtrate discharge ports 115, 115', and washes the cake 40 containing the electrode catalyst precursor remaining in the filtration chamber 112 in the pressure-in step S22. This can reduce the electrical conductivity ρ of the filtrate measured by the JIS standard test method (JIS K0522), and can reduce the halogen content, especially the chlorine content, of the electrode catalyst precursor.

[0033] In the forward washing step S23, it is preferable to switch the temperature of the washing water 43 when the electrical conductivity ρ of the filtrate becomes equal to or lower than a predetermined value during washing. For example, the washing water 43 can be switched from room temperature water (e.g., 23°C) to heated water (e.g., 70°C) when the electrical conductivity ρ of the filtrate becomes equal to or lower than a predetermined value. The predetermined value of the electrical conductivity ρ of the filtrate is preferably a value selected from the range of 20 to 40 μS / cm. The temperature of the room temperature water is preferably 20 to 25°C. The temperature of the heated water is preferably 60 to 80°C.

[0034] [Backwashing process] The backwashing step S24 is a step of supplying the washing water 43 from the filtrate discharge port 115 to the filtration chamber 112, passing the washing water 43 through the cake 40 containing the electrode catalyst precursor, and then discharging the washing water 43 from a different filtrate discharge port 115', which is different from the filtrate discharge port 115 for supplying the washing water 43, and is executed by the backwashing step execution means 34. FIG. 6 is a diagram of one dehydrator 104 in the washing device 13 of FIG. 2, and shows a preferred embodiment of the operating state in the backwashing step S24. The dehydrator 104 has, for example, at least two filtrate discharge ports 115, 115'. In contrast to the forward washing step S23, the backwashing step execution means 34 causes the washing water 43 to flow from the filtrate discharge port 115 toward the filtration chamber 112, thereby washing the cake 40 containing the electrode catalyst precursor remaining in the filtration chamber 112. The filtrate 42 is discharged, for example, from a different filtrate discharge port 115', which is different from the filtrate discharge port 115 for supplying the washing water 43. By carrying out the backwashing step S24, the electrical conductivity ρ of the filtrate can be further reduced, and the halogen content, particularly the chlorine content, of the electrode catalyst precursor can be further reduced.

[0035] In the backwashing step S24, washing may be performed with water at room temperature (e.g., 23°C), but since the electrical conductivity ρ of the filtrate has decreased to some extent at the end of the forward washing step S23, it is preferable to perform washing with heated water (e.g., 70°C) from the beginning. The temperature of the heated water is preferably 60 to 80°C.

[0036] [Opening process] The plate-opening step S25 is a step of opening the filter plates 111, 111' that form the filter chamber 112, and is executed by the plate-opening step executing means 35. Fig. 7 is a diagram of one dehydrator 104 in the cleaning device 13 of Fig. 2, showing a preferred embodiment of the operating state in the plate-opening step S25. The plate-opening step executing means 35 drives the electric cylinder 105 to move the pressing member 106 toward the rear frame 102, thereby releasing the clamping of the dehydrator 104. In this way, the two filter plates 111, 111' of the dehydrator 104 are pulled apart, and the filter chamber 112 is opened.

[0037] [Cake removal process] The cake peeling step S26 is a step of lowering the filter cloth to peel off and drop the cake 40 containing the dehydrated electrode catalyst precursor, and is executed by the cake peeling step execution means 36. FIG. 8 is a diagram of one dehydrator 104 in the cleaning device 13 of FIG. 2, showing a preferred embodiment of the operating state in the cake peeling step S26. When the two filter plates 111, 111' of the dehydrator 104 are separated by a predetermined distance by the cake peeling step execution means 36, the filter cloth 113 holding the cake 40 containing the electrode catalyst precursor travels downward. In this way, the cake 40 containing the electrode catalyst precursor is automatically peeled off from the filter cloth 113. Here, the moisture content (moisture content) of the cake 40 is a value obtained by dividing the weight of the moisture contained in the cake 40 by the weight of the catalyst powder contained in the cake 40 + the weight of the moisture, and the moisture content of the cake 40 at this time is preferably 60 to 80 wt%.

[0038] [Filter cloth cleaning process] The filter cloth washing step S27 is a step of washing the filter cloth 113 with washing water 43 after the cake peeling step S26, and is executed by the filter cloth washing step execution means 37. FIG. 9 is a diagram of one dehydrator 104 extracted from the washing device 13 in FIG. 2, and shows a preferred embodiment of the operating state in the filter cloth washing step S27. After the cake 40 containing the electrode catalyst precursor is peeled off from the filter cloth 113, the filter cloth 113 travels upward and returns to its original position. The filter cloth washing step execution means 37 supplies washing water 43 from a washing water pipe 117 provided below the dehydrator 104 by a pump (not shown) for washing the filter cloth while the filter cloth 113 is traveling upward. The washing water 43 is sprayed onto the filter cloth 113 to wash the filter cloth 113, preventing clogging of the filter cloth 113 and reliably recovering the electrode catalyst precursor and the like attached to the filter cloth 113. That is, since the wastewater during the cleaning of the filter cloth contains the electrode catalyst precursor, it is preferable to recover all of it. In this way, the electrode catalyst precursor attached to the filter cloth 113 is washed by flowing it away, thereby increasing the yield of the electrode catalyst precursor. In addition, for example, the amount of electrode catalyst precursor recovered can be further increased by cleaning the filter cloth 113 while repeatedly running it up and down.

[0039] [Compression process] In addition, a squeezing step may be performed after the forward washing step S23 and / or after the reverse washing step S24. The squeezing step is a step of further squeezing and dehydrating the cake 40 containing the electrode catalyst precursor, and is performed by a squeezing step execution means (not shown). FIG. 10 is a diagram of one dehydrator 104 extracted from the washing device 13 of FIG. 2, and shows a preferred embodiment of the operating state in the squeezing step. The squeezing step execution means injects pressurized water 119 into a diaphragm 118 provided on one filter plate 111', thereby further squeezing and dehydrating the cake 40 containing the electrode catalyst precursor. The squeezing step increases the solid content concentration of the cake 40 containing the electrode catalyst precursor, and produces a cake 40 containing the electrode catalyst precursor with an extremely low moisture content. Here, if the pressurized water 119 is removed from the diaphragm 118 after the squeezing step is completed, the pressure from the diaphragm 118 is eliminated, and the filter cloth 113 that was pressed by the diaphragm 118 can be easily peeled off from the cake 40, which is preferable. In this squeezing step, the other filter plate 111 may also be provided with a diaphragm (not shown). In this case, pressurized water can also be injected into the diaphragm (not shown) provided on the filter plate 111 side, so that the cake 40 containing the electrode catalyst precursor can be squeezed and dehydrated. In this case, it is also preferable to configure the pressurized water to be released from the diaphragm after the squeezing step is completed, since the pressing force from the diaphragm (not shown) is eliminated, and the filter cloth 113 that was pressed by the diaphragm (not shown) can be easily peeled off from the cake 40.

[0040] Although one dehydrator 104 has been described above, according to the cleaning device 13 as shown in FIG. 2, all the dehydrators 104 can operate in the same way, so that the amount of material that can be processed at one time by one device can be increased, and the production efficiency of the electrode catalyst can be improved. In addition, since the above-mentioned dehydrator 104 has a large filtration area and a high pressure-resistant structure, the processing speed can be improved. Furthermore, since the process can be fully automated from the introduction of the raw solution to the discharge of the cake and the cleaning of the device, the effort and time required for the cleaning process can be reduced. Furthermore, since resins, lining materials, etc. can be selected as the material for the device, the corrosion resistance of the device can be improved.

[0041] [Electrical conductivity of the filtrate ρ] The processing conditions, such as the forward washing time of the forward washing step S23 and the reverse washing time of the reverse washing step S24, are adjusted so that the electrical conductivity ρ of the filtrate obtained after the forward washing step S23 and / or the reverse washing step S24, measured by the JIS standard test method (JIS K0522), is equal to or less than a preset value. For example, the cleaning effect is increased by lengthening the cleaning time of the reverse washing step to the same extent as the cleaning time of the forward washing step. The same extent means a difference of 0 to 15 minutes (the absolute value of the difference between the cleaning time of the forward washing step and the cleaning time of the reverse washing step). In addition, the filtrate is a liquid discharged from a filtrate outlet after washing, and it is preferable to use all the filtrate discharged in that step.

[0042] The set value of the electrical conductivity ρ of the filtrate obtained after the forward cleaning step S23 is preferably a value selected from a range of 20 μS / cm or less. The set value of the electrical conductivity ρ of the filtrate obtained after the reverse cleaning step S24 is preferably a value selected from a range of 10 μS / cm or less. If the electrical conductivity ρ of the filtrate is 10 μS / cm or less, the concentrations of chlorine (Cl) species and bromine (Br) species contained in the electrode catalyst precursor are reduced to a level that allows practical use as an electrode catalyst for fuel cells.

[0043] The cleaning water 43 used in the cleaning device 13 may be pure water such as ultrapure water, but does not have to be pure water. i Ion-exchanged water or the like having a conductivity of less than 10 μS / cm can be used.

[0044] (drying equipment) The drying device 14 dries the electrode catalyst precursor 41 after cleaning by the above-mentioned cleaning device 13. The drying device 14 includes a drying step execution means 51 that executes a drying step for drying the electrode catalyst precursor 41 after cleaning by the cleaning device 13. As a drying method in the drying step, in addition to a conventional drying method using a shelf vacuum dryer (not shown) in which the crushed electrode catalyst precursor is arranged on a shelf and vacuum-dried, a drying method using a Ribocone (not shown) or a PV mixer (not shown) can be used.

[0045] <Catalyst for electrodes> The structure of the electrode catalyst produced in this embodiment is not particularly limited, and may be a structure in which precious metal catalyst particles are supported on a conductive support (conductive carbon support, conductive metal oxide support, etc.). For example, it may be a so-called Pt catalyst, a Pt alloy catalyst (PtCo catalyst, PtNi catalyst, etc.), or a so-called core-shell catalyst having a core-shell structure.

[0046] For example, in the case of a core-shell catalyst having a configuration in which palladium is used as the constituent element of the core portion 4 and platinum is used as the constituent element of the shell portion 5, materials containing chlorine (Cl) species such as chloride salts of platinum (Pt) and chloride salts of palladium (Pd) are often used as raw materials. According to the manufacturing system and manufacturing method of the electrode catalyst of this embodiment, it is possible to manufacture an electrode catalyst with a reduced content of these chlorine (Cl) species.

[0047] An example of the structure of an electrode catalyst will be described in more detail with reference to the drawings. As shown in Fig. 11, an electrode catalyst 1 having a core-shell structure includes a carrier 2 and a catalyst particle 3 supported on the carrier 2. The catalyst particle 3 includes a core portion 4 and a shell portion 5 formed so as to cover at least a part of the core portion 4. The catalyst particle 3 has a so-called core-shell structure including the core portion 4 and the shell portion 5 formed on the core portion 4.

[0048] That is, the electrode catalyst 1 has catalyst particles 3 supported on a carrier 2, and the catalyst particles 3 have a structure in which a core portion 4 serves as a nucleus (core) and a shell portion 5 serves as a shell that covers the surface of the core portion 4. In addition, the constituent elements (chemical composition) of the core portion 4 and the constituent elements (chemical composition) of the shell portion 5 have different compositions.

[0049] Further, as a specific example of the core-shell structure, in FIG. 12, an electrode catalyst 1A has a catalyst particle 3a composed of a core portion 4, a shell portion 5a covering a part of the surface of the core portion 4, and a shell portion 5b covering another part of the surface of the core portion 4. In addition, in FIG. 13, an electrode catalyst 1B has a catalyst particle 3 composed of a core portion 4 and a shell portion 5 covering almost the entire surface of the core portion 4, and the shell portion 5 has a two-layer structure including a first shell portion 6 and a second shell portion 7. Furthermore, in FIG. 14, an electrode catalyst 1C has a catalyst particle 3a composed of a core portion 4, a shell portion 5a covering a part of the surface of the core portion 4, and a shell portion 5b covering another part of the surface of the core portion 4, and the shell portion 5a has a two-layer structure including a first shell portion 6a and a second shell portion 7a, and the shell portion 5b has a two-layer structure including a first shell portion 6b and a second shell portion 7b.

[0050] In this embodiment, the chlorine (Cl) species refers to a chemical species containing chlorine as a constituent element. Specifically, the chemical species containing chlorine include chlorine atoms (Cl), chlorine molecules (Cl), and chloride ions (Cl - ), chlorine radical (Cl·), polyatomic chloride ions, and chlorine compounds (such as X-Cl, where X is a counterion).

[0051] In this embodiment, the bromine (Br) species refers to a chemical species containing bromine as a constituent element. Specifically, the chemical species containing bromine include bromine atoms (Br), bromine molecules (Br), bromide ions (Br - ), the bromine radical (Br ), polyatomic bromide ions, and bromine compounds (such as X-Br, where X is a counterion).

[0052] <Method of manufacturing electrode catalyst> 15, the electrode catalyst manufacturing method according to this embodiment includes an electrode catalyst precursor manufacturing step S1 for manufacturing an electrode catalyst precursor, which is a raw material for an electrode catalyst, a washing step S2 for washing, by a filter press, a liquid 30 containing the electrode catalyst precursor manufactured in the electrode catalyst precursor manufacturing step S1, and a drying step S3 for drying the electrode catalyst precursor 41 after washing in the washing step S2. Each of steps S1, S2, and S3 can be performed by an electrode catalyst precursor manufacturing apparatus 12, a washing apparatus 13, and a drying apparatus 14, respectively, of the electrode catalyst manufacturing system 10 described above.

[0053] As shown in Fig. 16, the cleaning step S2 includes a plate closing step S21, a press-in step S22, a forward cleaning step S23, a reverse cleaning step S24, a plate opening step S25, a cake peeling step S26, and a filter cloth cleaning step S27. In the cleaning step S2, the electrode catalyst precursor-containing liquid 30 produced in the electrode catalyst precursor production step S1 is cleaned, filtered, and dehydrated to obtain a cleaned electrode catalyst precursor 41. In addition, a squeezing step may be performed after the forward cleaning step S23 and / or after the reverse cleaning step S24. The configuration of each step S21 to S27 and the squeezing step is as described in the above-mentioned <electrode catalyst production system> (cleaning device). EXAMPLES

[0054] The examples described herein are illustrative of embodiments of the invention and should not be construed as limiting the scope of the invention.

[0055] <Production of electrode catalyst precursor (reaction process, electrode catalyst precursor production step)> (Production Example 1) As a precursor of the electrode catalyst precursor, a precursor of a Pt particle-supported carbon catalyst (hereinafter referred to as "Pt / C catalyst", manufactured by NECHEMCAT, Pt support rate 50 wt%, product name: "SA50BK") was produced.

[0056] The carrier for this precursor was a commercially available conductive hollow carbon carrier {manufactured by Lion Corporation, trade name "Carbon ECP" (registered trademark) (Ketjen Black EC300J), specific surface area 750 to 800 m2}. 2 A water-soluble reducing agent was added to water containing this carrier and a water-soluble Pt salt, and the reduction reaction of the Pt component was allowed to proceed at a predetermined temperature, thereby preparing an electrode catalyst precursor used in this embodiment.

[0057] [Preparation of liquid (stock solution) containing electrode catalyst precursor] The liquid containing the electrode catalyst precursor obtained as described above was dispersed in a kettle without being dried, and used as a stock solution to be treated in a cleaning device.

[0058] <Production of electrode catalyst> Example 1 [Processing using cleaning equipment (cleaning step)] The liquid containing the electrode catalyst precursor obtained in Production Example 1 was introduced into a cleaning device, and a cleaning process was carried out. The processing time for each process in the cleaning device is shown in Table 1. First, the pressing process was carried out for 20 minutes. The thickness of the cake containing the electrode catalyst precursor in the pressing process was set to 5 to 10 mm.

[0059] The thickness of this cake is within a range of thickness that is previously determined through preliminary experiments, taking into consideration the degree of cleaning and cleaning time required for the electrode catalyst precursor to be used.

[0060] Next, the forward washing step was carried out. In the forward washing step, the filtrate was first treated with washing water at room temperature (23°C) for 24 minutes, and when the electrical conductivity ρ of the filtrate became 40 μS / cm or less, the water was switched to heated water (70°C) and treated with heated water for 50 minutes. After the forward washing step, a squeezing step was carried out for 5 minutes. Then, a reverse washing step was carried out, and in the reverse washing step, the filtrate was treated with heated water (70°C) for 73 minutes. The washing process was carried out for a total of about 2.9 hours.

[0061] Ion-exchanged water was used for washing. The electrical conductivity of the ion-exchanged water used at room temperature (23°C) was i is 7.70μS / cm, and electrical conductivity ρ when heated (70℃) i is 4.6μS / cm.

[0062] [Treatment using a drying device (drying step)] The cake containing the electrode catalyst precursor obtained after the treatment with the washing device was dried in a drying device at a temperature of 70° C. in air for 24 hours to obtain an electrode catalyst.

[0063] Comparative Example 1 [Processing using cleaning equipment (cleaning step)] The liquid containing the electrode catalyst precursor obtained in Production Example 1 was introduced into a cleaning device, and a cleaning process was carried out. The processing time for each process in the cleaning device is shown in Table 1. First, the pressing process was carried out for 40 minutes. The thickness of the cake containing the electrode catalyst precursor in the pressing process was set to 11 to 15 mm.

[0064] The thickness of this cake is in a range outside the range of thicknesses previously determined by preliminary experiments, taking into consideration the degree of cleaning and cleaning time required for the electrode catalyst precursor to be used.

[0065] Next, the forward washing step was carried out. In the forward washing step, the mixture was first treated with room temperature (23°C) washing water for 33 minutes, and when the electrical conductivity ρ of the filtrate became 40μS / cm or less, the water was switched to heated water (70°C) and treated with heated water for 60 minutes. After the forward washing step, the squeezing step was carried out for 5 minutes, followed by the reverse washing step. However, since the electrical conductivity ρ of the filtrate did not change from the electrical conductivity ρ of the filtrate at the end of the forward washing step, the reverse washing step was carried out for 36 minutes, i.e., after a total of about 2.9 hours of washing, the treatment was interrupted.

[0066] Ion-exchanged water was used for washing. The electrical conductivity of the ion-exchanged water used at room temperature (23°C) was i is 7.70μS / cm, and electrical conductivity ρ when heated (70℃) i is 4.6μS / cm.

[0067] [Treatment using a drying device (drying step)] The cake containing the electrode catalyst precursor obtained after the treatment with the washing device was dried in a drying device at a temperature of 70° C. in air for 24 hours to obtain an electrode catalyst.

[0068] [Table 1]

[0069] Comparative Example 2 The liquid containing the electrode catalyst precursor obtained in Production Example 1 was introduced into a centrifuge and subjected to a washing treatment. Washing was repeated until the electrical conductivity ρ of the filtrate measured by the JIS standard test method (JIS K0522) was 10 μS / cm or less, and the obtained electrode catalyst precursor was dispersed in ultrapure water to prepare a dispersion, which was then filtered. The residue obtained by filtration was dried in a drying device at a temperature of 70° C. in air for 24 hours to obtain an electrode catalyst.

[0070] <Evaluation Results> As shown in Table 1, in Example 1, the electrical conductivity ρ of the filtrate at the end of the forward washing step was 15.9 μS / cm, whereas the electrical conductivity ρ of the filtrate at the end of the reverse washing step was reduced to 9.7 μS / cm. The electrical conductivity ρ of the filtrate could be reduced to 10 μS / cm or less with a washing treatment time of less than 3 hours. On the other hand, in Comparative Example 1, the electrical conductivity ρ of the filtrate at the end of the forward washing step was reduced to 19.3 μS / cm, but even after the reverse washing step was performed thereafter, it did not decrease at all from 19.3 μS / cm. In Comparative Example 2, in which washing was performed using a centrifuge as in the past, it took 15 to 19 hours to reduce the electrical conductivity ρ of the filtrate to 10 μS / cm or less after three times of operation. Table 2 shows a comparison of the treatment times of Example 1 and Comparative Example 2. In Table 2, the treatment time from the raw material feed to solid-liquid separation and the time required for cake washing and dehydration are shown separately.

[0071] [Table 2]

[0072] Therefore, according to the electrode catalyst manufacturing system and manufacturing method of this embodiment, the time required for processing by the washing device (washing step) can be significantly reduced to 1 / 5 or less compared to processing using a conventional centrifuge. Furthermore, in the washing device according to this embodiment, the cake containing the electrode catalyst precursor is automatically peeled off, eliminating the need for an operator to scrape off the electrode catalyst precursor, and significantly reducing the effort required.

[0073] Although the present invention has been described above based on the embodiment and examples, the present invention can be embodied in various modified forms. In particular, the electrode catalyst precursor manufacturing apparatus 12 (reaction step, electrode catalyst precursor manufacturing apparatus step S1) and the drying apparatus 14 (drying step S3) are not particularly limited, and various modified forms can be adopted. In addition, the structure of the cleaning apparatus 13 is not limited to that shown in FIG. 2, and the structure of the filter chamber 112 is not limited to that shown in FIGS. 3 to 10, and various modified forms can be adopted as long as they have a structure that can obtain similar effects in each of steps S21 to S27 of the cleaning step S2 according to this embodiment and in the squeezing step. [Explanation of symbols]

[0074] 1 Electrode catalyst 2. Carrier 3. Catalyst particles 4 Core 5 Shell 10. Electrode catalyst manufacturing system 12 Electrode catalyst precursor production equipment 13 Cleaning equipment 14 Drying equipment 30 Liquid containing electrode catalyst precursor (raw solution) 40 Cake containing electrode catalyst precursor 41 Electrode catalyst precursor after cleaning 42 Filtrate 43 Washing water 111,111' Filter plate 112 Room 113 Cloth 114 Stock solution supply pipe 115,115' Filtrate outlet 116 Filtration Bed T is the thickness of the cake containing the electrode catalyst precursor S1 Electrode catalyst precursor manufacturing step S2 Wash step S3 Drying step S21 Closing process S22 Press-in process S23 Forward cleaning process S24 Backwashing process S25 Opening process S26 Cake peeling process S27 Filter cloth cleaning process ρ Electrical conductivity of the filtrate ρ i Electrical conductivity of ion-exchanged water [Industrial Applicability]

[0075] According to the electrode catalyst manufacturing system and manufacturing method of the present invention, the labor and time required to manufacture an electrode catalyst having a low halogen content, particularly a low chlorine content, can be significantly reduced by eliminating the need for workers to scrape off the electrode catalyst precursor and shortening the time required to wash the electrode catalyst precursor.

[0076] Therefore, the present invention is a manufacturing system and method for electrode catalysts that can be applied not only to the electrical equipment industry, such as fuel cells, fuel cell vehicles, and portable mobile devices, but also to ENE-FARMs and cogeneration systems, and will contribute to the development of the energy industry and environmental technologies.

Claims

1. an electrode catalyst precursor manufacturing apparatus for manufacturing an electrode catalyst precursor, which is a raw material for an electrode catalyst including a conductive support and catalyst particles supported on the conductive support; a cleaning device for cleaning the electrode catalyst precursor by a filter press; a drying device that dries the electrode catalyst precursor after being washed by the washing device, The cleaning device includes: a closing step of fastening the filter plate to form a filter chamber; a pressure-injection step of injecting a liquid containing the electrode catalyst precursor from a raw liquid supply pipe into the filtration chamber under pressure, filtering the liquid, and discharging the filtrate from a filtrate discharge port; a forward washing step of supplying washing water from the raw solution supply pipe to the filtration chamber, causing the washing water to pass through a cake containing the electrode catalyst precursor, and then discharging the filtrate from the filtrate discharge port; a backwashing step of supplying washing water from the filtrate discharge port to the filtration chamber, passing the washing water through the cake containing the electrode catalyst precursor, and then discharging the washing water from a filtrate discharge port different from the filtrate discharge port through which the washing water is supplied; a plate opening step of opening the filter plate forming the filter chamber; a cake peeling step of lowering a filter cloth to peel off and drop the cake containing the electrode catalyst precursor, In the pressing step, the cake is formed to have a thickness within a range that is experimentally determined in advance, taking into consideration the cleaning degree and cleaning time required for the electrode catalyst precursor to be used. A manufacturing system for electrode catalysts.

2. When the conductive support is conductive carbon, 2. The system for manufacturing an electrode catalyst according to claim 1, wherein the cake containing the electrode catalyst precursor during the pressing step has a thickness of 5 to 10 mm.

3. 3. The system for producing an electrode catalyst according to claim 1, wherein the cleaning device further comprises a means for performing a filter cloth cleaning step of cleaning the filter cloth with cleaning water after the cake peeling step.

4. 4. The system for producing an electrode catalyst according to claim 1, wherein a cleaning time in the reverse cleaning step is approximately the same as a cleaning time in the forward cleaning step.

5. 5. The system for manufacturing an electrode catalyst according to claim 1, wherein the cake separated and dropped in the cake separating step has a moisture content of 60 to 80 wt %.

6. an electrode catalyst precursor manufacturing step of manufacturing an electrode catalyst precursor, which is a raw material of an electrode catalyst including a conductive support and catalyst particles supported on the conductive support; a washing step of washing the electrode catalyst precursor by a filter press; a drying step of drying the electrode catalyst precursor after washing in the washing step, The washing step comprises: a closing step of fastening the filter plate to form a filter chamber; a pressure-injection step of injecting a liquid containing the electrode catalyst precursor from a raw liquid supply pipe into the filtration chamber under pressure, filtering the liquid, and discharging the filtrate from a filtrate discharge port; a forward washing step of supplying washing water from the raw solution supply pipe to the filtration chamber, causing the washing water to pass through a cake containing the electrode catalyst precursor, and then discharging the filtrate from the filtrate discharge port; a backwashing step of supplying washing water from the filtrate discharge port to the filtration chamber, passing the washing water through the cake containing the electrode catalyst precursor, and then discharging the washing water from a filtrate discharge port different from the filtrate discharge port through which the washing water is supplied; a plate opening step of opening the filter plate forming the filter chamber; and a cake peeling step of lowering a filter cloth to peel off and drop the cake containing the electrode catalyst precursor, In the pressing step, the cake is formed to have a thickness within a range that is experimentally determined in advance, taking into consideration the cleaning degree and cleaning time required for the electrode catalyst precursor to be used. A method for producing an electrode catalyst.

7. When the conductive support is conductive carbon, 7. The method for producing an electrode catalyst according to claim 6, wherein the cake containing the electrode catalyst precursor during the pressing step has a thickness of 5 to 10 mm.

8. The method for producing an electrode catalyst according to claim 6 or 7, wherein the washing step further comprises a filter cloth washing step of washing the filter cloth with washing water after the cake peeling step.

9. The method for producing an electrode catalyst according to any one of claims 6 to 8, wherein a cleaning time in the reverse cleaning step is approximately the same as a cleaning time in the forward cleaning step.

10. The method for producing an electrode catalyst according to any one of claims 6 to 9, wherein the cake separated and dropped in the cake separating step has a moisture content of 60 to 80 wt %.

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