Metal catalyst composite comprising carbon support prepared using polystyrene-based material, and preparation method therefor

Abstract

A method for preparing a metal catalyst composite, according to one embodiment of the present invention, comprises: a first step of dispersing a polystyrene-based material in a first solvent, and then hyper-crosslinking same so as to obtain a hyper-crosslinked product; a second step of crushing the hyper-crosslinked product; a third step of carbonizing the crushed hyper-crosslinked product so as to prepare carbonized polystyrene-based particles; and a fourth step of dispersing the carbonized polystyrene-based particles in a second solvent, mixing a precursor of a catalytic metal, and then reducing same so as to prepare a metal catalyst composite.

Description

Metal catalyst composite comprising a carbon support manufactured using a polystyrene series material and a method for manufacturing the same

[0001] The present invention relates to a metal catalyst composite including a carbon support manufactured using a polystyrene series material and a method for manufacturing the same.

[0002]

[0003] A fuel cell is a type of power generation device that converts the chemical energy of fuel into electrical energy through an electrochemical reaction within a fuel cell stack rather than converting it into heat through combustion. It not only supplies electricity for industrial, household, and vehicle use, but can also be applied to supplying electricity to small electric / electronic products, especially portable devices. These fuel cells come in various types depending on the type of fuel and electrolyte used, and can be classified by fuel type into polymer electrolyte membrane fuel cells (PEMFC), direct methanol fuel cells (DMFC), phosphoric acid fuel cells (PAFC), solid oxide fuel cells (SOFC), and alkaline electrolyte fuel cells (AFC). Among these, polymer electrolyte membrane fuel cells have the advantages of low operating temperature, prevention of leakage problems due to the use of solid electrolytes, and fast operation. Compared to other types of fuel cells, they are high-power fuel cells with high current density, operate at temperatures below 100°C, have a simple structure, fast start-up and response characteristics, and have excellent durability. In addition to hydrogen, methanol or natural gas can be used as fuel.

[0004] Factors that must be improved for the commercialization of polymer electrolyte membrane fuel cells include improved performance, extended lifespan, and lower cost. The component that most significantly influences these factors is the membrane electrode assembly (MEA). The MEA is the unit cell structure of the fuel cell, and it consists of an electrolyte membrane made of a polymer material, with an anode and a cathode coated on both sides. This MEA is where the electrochemical reaction between hydrogen and oxygen occurs and is composed of the cathode, the anode, and the electrolyte membrane, i.e., the ion-conducting electrolyte membrane. At the anode, the fuel oxidizes to produce hydrogen ions and electrons. The hydrogen ions then migrate to the cathode through the electrolyte membrane. At the cathode, the hydrogen ions and electrons transferred through the oxygen and electrolyte membrane react to produce water. This reaction causes electrons to move to the external circuit.

[0005] The efficiency of these fuel cells is largely determined by the reaction rate of the electrodes (anode, cathode), and nano-sized catalysts can be used as electrode materials.

[0006] Conventional catalysts typically have polymer-based carbon particles forming the support, with an average particle diameter exceeding approximately 100 nm. These particles vary in size and variability across the particle, resulting in insufficient or inconsistent support of metal-based materials. Furthermore, catalysts containing the support may lack sufficient durability and struggle to maintain stable performance over long periods of time.

[0007]

[0008] One embodiment of the present invention is to provide a metal catalyst composite capable of improving the performance of a membrane-electrode assembly.

[0009] One embodiment of the present invention is to provide a metal catalyst composite having excellent performance of a membrane-electrode assembly while reducing the amount of platinum (Pt) used.

[0010] One embodiment of the present invention provides a method for producing a metal catalyst composite having an average particle size of less than 50 nm.

[0011] One embodiment of the present invention provides a method for producing a metal catalyst composite having excellent performance, durability, and long-term stability.

[0012] One embodiment of the present invention provides a method for producing a metal catalyst composite capable of increasing the specific surface area of ​​a support of the metal catalyst composite.

[0013] One embodiment of the present invention is to provide a metal catalyst composite having an increased metal catalyst loading amount.

[0014] One embodiment of the present invention provides a method for producing a metal catalyst composite capable of mass-producing a metal catalyst composite of uniform size.

[0015] In addition to the above-mentioned tasks, embodiments according to the present invention can be used to achieve other tasks not specifically mentioned.

[0016]

[0017] A method for producing a metal catalyst composite according to one embodiment of the present invention comprises a first step of dispersing a polystyrene-based material in a first solvent and then hyper-crosslinking to obtain a hyper-crosslinked product, a second step of crushing the hyper-crosslinked product, a third step of carbonizing the crushed hyper-crosslinked product to produce carbonized polystyrene-based particles, and a fourth step of dispersing the carbonized polystyrene-based particles in a second solvent, mixing in a precursor of a catalyst metal, and then reducing the carbonized polystyrene-based particles to produce a metal catalyst composite.

[0018] The metal catalyst composite may include carbonized polystyrene particles and a catalyst layer positioned on the carbonized polystyrene particles, and the catalyst layer may include a catalytic metal.

[0019] The catalytic metal may include one or more of platinum (Pt), palladium (Pd), ruthenium (Ru), iridium (Ir), nickel (Ni), cobalt (Co), or iron (Fe).

[0020] The catalytic metal may include one or more of platinum (Pt), palladium (Pd), ruthenium (Ru), iridium (Ir), nickel (Ni), cobalt (Co), or iron (Fe).

[0021] The fourth step may include a step of preparing a dispersion in which carbonized polystyrene particles are dispersed in a second solvent, a step of adjusting the pH of the dispersion and then raising the temperature, a step of adding a precursor solution containing a precursor of a catalyst metal to the dispersion and then stirring, and a step of preparing a metal catalyst complex by reducing the precursor of the catalyst metal.

[0022] The second solvent may include ethylene glycol.

[0023] The step of adjusting the pH of the dispersion and then raising the temperature may include a step of stirring the dispersion at 40 to 60°C, a step of adjusting the pH of the dispersion by adding NaOH, and a step of raising the temperature to 100 to 120°C.

[0024] The step of preparing a metal catalyst complex by reducing a precursor of a catalytic metal can be performed at a temperature range of 400 to 800°C for 10 minutes to 2 hours.

[0025] The first step may be to disperse a polystyrene series material in a first solvent, add a crosslinking catalyst and a crosslinking agent, stir, and then raise the temperature to produce a hyper-crosslinked product.

[0026] The crosslinking catalyst may include one or more of FeCl3, FeCl3·6H2O, AlCl3, CoCl3, ZnCl3, or CrCl4.

[0027] The crosslinking agent may include one or more of formaldehyde dimethyl acetal, trichloromethane, or carbon tetrachloride.

[0028] The first solvent may comprise dichloroethane.

[0029] The average particle diameter of the metal catalyst complex may be less than 50 nm.

[0030] The polystyrene-based material may include one or more of polystyrene granules, polystyrene beads, polystyrene flakes, expanded polystyrene, or expanded polystyrene.

[0031] Polystyrene family materials may include waste polystyrene.

[0032] A metal catalyst composite according to one embodiment of the present invention is manufactured by the method for manufacturing the metal catalyst composite.

[0033] A membrane-electrode assembly according to one embodiment of the present invention comprises a polymer electrolyte membrane, and an electrode positioned on one or the other surface of the polymer electrolyte membrane, the electrode comprising a metal catalyst complex manufactured by the method for manufacturing the metal catalyst complex.

[0034]

[0035] A metal catalyst composite manufactured by a method for manufacturing a metal catalyst composite according to one embodiment of the present invention can improve the performance of a membrane-electrode assembly, and at the same time, can significantly reduce the amount of platinum (Pt) used, can have excellent performance, durability, and long-term stability, can increase the specific surface area of ​​the support of the metal catalyst composite, and can increase the amount of metal catalyst supported.

[0036] In addition, the size of the metal catalyst complex and the support manufactured by the method for manufacturing the metal catalyst complex according to one embodiment of the present invention can be uniform, and the amount of metal catalyst supported per unit volume can be constant.

[0037] Additionally, the average particle size of the support of the metal catalyst complex may be less than 50 nm.

[0038] In addition, the method for manufacturing a metal catalyst composite according to one embodiment of the present invention can mass-produce a metal catalyst composite of uniform size.

[0039]

[0040] Figure 1a is a scanning electron microscope result for a PtCo / Carbon catalyst composite manufactured according to Example 1.

[0041] Figure 1b is a scanning electron microscope result for a PtCo / Carbon catalyst composite manufactured according to Example 5.

[0042] Figure 2a shows the results of a half-cell test for a metal catalyst composite manufactured according to Example 1.

[0043] Figure 2b shows the half-cell test results for the metal catalyst composite manufactured according to Example 5.

[0044] Figure 2c shows the half-cell test results for a commercial catalyst (Pt / Carbon).

[0045] Figures 3a and 3b show the results of full-cell tests using metal catalyst composites manufactured according to Examples 1 to 4, Comparative Examples 1 and 2, and a commercial catalyst (Pt / Carbon).

[0046] Figures 3c and 3d show the results of a full-cell test using the metal catalyst composites manufactured according to Examples 5 to 8.

[0047]

[0048]

[0049] The total stirring time, including the initial stirring time of the dispersion and the additional stirring time after the temperature increase, is preferably about 2 hours or more, and more preferably can be performed in the range of about 2 to 6 hours. This stirring time has a significant effect on the penetration depth of the metal precursor into the carbonized particles and the uniformity of metal adsorption on the particle surface, and by optimizing it, it can contribute to the formation of active sites of the catalyst and improvement of the electrochemical performance of the catalyst.

[0050] Afterwards, the precursor solution is added to the prepared solution (dispersion), stirred at about 140 to 180°C for about 1 to 5 hours, and then washed and dried to obtain a powder.

[0051] When the catalyst layer is to be formed of two or more layers, the prepared precursor solutions are sequentially added and stirred. For example, after adding the precursor solution corresponding to the first catalyst layer, the mixture is stirred at about 140 to 180°C for about 1 to 5 hours, and then, after adding the precursor solution corresponding to the first catalyst layer, the mixture is stirred at about 140 to 180°C for about 1 to 5 hours, and then washed and dried to obtain a powder.

[0052] Next, the obtained powder is reduced at about 400 to 800°C for about 10 minutes to 2 hours in a hydrogen / nitrogen flow to produce a metal catalyst composite. The reduction process may be performed in a hydrogen / nitrogen atmosphere. In this step, the catalytic metal may be formed in the form of a catalyst layer on carbonized polystyrene particles (support).

[0053] The manufactured metal catalyst composite may include, for example, carbonized polystyrene particles and a catalyst layer positioned on the carbonized polystyrene particles, and the catalyst layer may include a catalytic metal.

[0054] In the case where a catalyst layer is to be formed of two or more layers (core-shell structure), each metal precursor solution is sequentially added and stirred to produce metal nanoparticles having a core-shell structure. For example, in order to form a metal including nickel (Ni), iron (Fe), palladium (Pd) or a combination thereof into a core structure, a precursor of the metal (e.g., Ni(NO3)2·6H2O, FeCl3·6H2O, PdCl2, etc.) is added, and then a reduction reaction is carried out while stirring at about 140 to 180°C for about 1 to 5 hours. Next, a precursor solution such as H₂PtCl6·6H2O, RuCl3, or IrCl3 is added to form a shell structure containing a precious metal such as platinum (Pt), ruthenium (Ru), or iridium (Ir), and stirred under the same conditions (stirring at about 140 to 180°C for about 1 to 5 hours) so that the precious metal is uniformly deposited on the surface of the core metal particle.

[0055] Thereafter, the catalyst precursor having the core-shell structure produced is washed and dried to obtain a catalyst precursor powder. Subsequently, a step of mixing the obtained core-shell catalyst precursor with a carbon support is performed. At this time, the carbon support may be composed of, for example, carbonized polystyrene copolymer particles, and the catalyst precursor powder is added and stirred while dispersed in a solvent such as ethanol, isopropanol, or distilled water, so that the catalyst particles can be uniformly supported on the surface of the support. This mixture is filtered, washed, and dried to produce a carbon support composite having a catalyst supported thereon.

[0056] Next, the obtained complex is heat-treated at approximately 400 to 800°C for approximately 10 minutes to 2 hours in a nitrogen flow or hydrogen / nitrogen mixed atmosphere to produce a core-shell structured metal catalyst complex. This reduction process stabilizes the core-shell structure and modulates the electronic structure and lattice gap, thereby enhancing catalytic activity.

[0057] The manufactured metal catalyst complex may include, for example, carbonized polystyrene-based copolymer particles (carbon support) and core-shell structured metal nanoparticles supported on the surface of the support. In this case, the core-shell structured catalyst layer has a non-precious metal or transition metal such as Ni, Fe, Pd, etc. positioned at the center (core), and a precious metal such as Pt, Ru, Ir, etc. uniformly formed at the outside (shell), and can exhibit high catalytic activity for the oxygen reduction reaction (ORR).

[0058] Furthermore, unlike conventional techniques, the manufacturing method according to the present invention allows for the direct formation of a core-shell metal catalyst on the surface of a carbon support without the use of separate materials such as binders or adhesives, thereby simplifying the process and reducing manufacturing costs. This core-shell structure is highly effective in that it enables the realization of a highly active and durable catalyst while reducing the amount of platinum used.

[0059] Furthermore, in the case of the metal catalyst composite according to the embodiment, the catalyst layer is very firmly bonded to the carbon support, so that it is hardly separated even under conditions such as high temperatures and high pressures, and can be stably maintained for a long period of time. Therefore, the excellent performance of the metal catalyst composite can be maintained for a long period of time, and the durability and long-term stability of the metal catalyst composite can be significantly improved.

[0060] In addition, the metal catalyst complex according to the embodiment has a very large specific surface area, the amount of catalyst metal supported can be increased, the range of the amount of catalyst metal supported can be expanded to 1 to 70%, and the amount of catalyst metal supported can be freely controlled.

[0061] The amount of catalyst metal supported can be freely adjusted within the range of 1 to 70 wt% by controlling precursor concentration, pH, and reduction temperature conditions, and particle size uniformity can be maintained.

[0062] In addition, the metal catalyst composite according to the embodiment can exhibit excellent performance and durability while reducing the amount of platinum (Pt) used to 1 / 4 compared to a conventional metal catalyst composite.

[0063] The average particle diameter of the metal catalyst complex is less than about 50 nm, and may be, for example, about 20 to 45 nm.

[0064] A membrane-electrode assembly (MEA) according to one embodiment of the present invention includes a polymer electrolyte membrane and an electrode positioned on one or the other surface of the polymer electrolyte membrane, wherein the electrode may include a metal catalyst complex.

[0065] A metal catalyst composite according to one embodiment of the present invention is compatible with various electrolyte membranes, such as PFSA, Fumapem, and Aquivion, in addition to Nafion, and can exhibit high adhesion and electrochemical stability on the membrane surface.

[0066] The metal catalyst complex according to the embodiment can also be manufactured in the form of an ink that can be directly applied onto a film, and can be suitable for automation and continuous production due to its high integration with the MEA manufacturing process.

[0067] The membrane-electrode assembly according to the embodiment has superior efficiency, performance, durability and long-term stability compared to the prior art.

[0068] These metal catalyst composites and membrane-electrode assemblies can be applied to various technical fields. For example, the metal catalyst composites can be applied as cathode catalysts in fuel cells as oxygen reduction catalysts and as hydrogen oxidation catalysts (anode catalysts).

[0069] In addition, metal catalyst composites can be applied in various ways, such as water electrolysis catalysts (HER / OER), secondary battery cathode materials, CO2 reduction reaction catalysts, supercapacitor electrodes, and catalytic sensors.

[0070] In particular, the physical properties of the carbonized particles may vary depending on the source of the polystyrene (e.g., product packaging, building insulation, appliance cushioning), which may also result in different optimal catalyst loading process conditions. The embodiments of the present invention provide optimized conditions for these various types of waste resources, thereby simultaneously ensuring environmental friendliness and economic feasibility in resource recycling.

[0071] Hereinafter, the present invention will be described with examples, comparative examples, and experimental examples. However, the present invention is not limited thereto.

[0072]

[0073] Example 1

[0074] Polystyrene beads (5 g) having a weight-average molecular weight (Mw) of approximately 35,000 were dispersed in dichloroethane. Then, FeCl3 (10 g) was added to the solution, and formaldehyde dimethyl acetal (10 ml) was slowly poured. The solution was stirred at approximately 50°C for approximately 2 hours, then the temperature was increased to 80°C and crosslinked for approximately 24 hours. To remove excess FeCl3, the solution was washed with a mixture containing 90 wt% ethanol and 10 wt% hydrochloric acid, filtered, and dried for approximately 12 hours.

[0075] The hyper-crosslinked resultant was sufficiently crushed using ball milling. The crushed resultant was carbonized at approximately 900°C for 2 hours in a nitrogen flow at a ramping rate of 2°C / min to obtain carbonized polystyrene particles.

[0076] 500 mg of the carbonized product was dispersed in 20 mL of ethylene glycol. To deposit cobalt atoms (Co) and platinum atoms (Pt), Co(NO3)2·6H2O (675 mg) and H2PtCl6·6H2O (85 mg) were added to 2 mL of ultrapure water to prepare a PtCo precursor mixture. The ethylene glycol solution in which the carbonized particles were dispersed was mixed at about 50 °C for about 5 minutes, adjusted to pH 14 using 1 M NaOH, and then heated to about 110 °C. After adding the PtCo precursor mixture, the mixture was stirred at about 160 °C for about 3 hours. The mixture was then washed, and the product was dried under vacuum at 50 °C. Afterwards, the powder was reduced at about 500°C for 1 h under a H2 / N2 flow rate (10:190 sccm) in a hydrogen / nitrogen flow at a ramping rate of 2°C / min. Finally, the PtCo / Carbon particle catalyst (metal catalyst composite) was obtained as a black powder. The platinum content of the catalyst was controlled to 5 wt%.

[0077]

[0078] Example 2

[0079] A PtCo / Carbon particle catalyst (metal catalyst composite) was prepared in the same manner as in Example 1, except that polystyrene beads having a weight-average molecular weight (Mw) of approximately 192,000 were used.

[0080]

[0081] Example 3

[0082] A PtCo / Carbon particle catalyst (metal catalyst composite) was prepared in the same manner as in Example 1, except that polystyrene beads having a weight-average molecular weight (Mw) of approximately 280,000 were used.

[0083]

[0084] Example 4

[0085] A PtCo / Carbon particle catalyst (metal catalyst composite) was prepared in the same manner as in Example 1, except that polystyrene beads having a weight-average molecular weight (Mw) of approximately 400,000 were used.

[0086]

[0087] Example 5

[0088] A PtCo / Carbon particle catalyst (metal catalyst composite) was prepared in the same manner as in Example 1, except that 5 g of waste polystyrene (container house insulation, type 1 bead-type Styrofoam) used as building insulation was used instead of 5 g of polystyrene beads having a weight-average molecular weight (Mw) of approximately 35,000.

[0089]

[0090] Example 6

[0091] A PtCo / Carbon particle catalyst (metal catalyst composite) was prepared in the same manner as in Example 1, except that 5 g of waste polystyrene (waste styrofoam compressed using a friction-type shrinker (SH-40M model) of Dongkwang Environment Co., Ltd.) used as a recycled ingot was used instead of 5 g of polystyrene beads having a weight-average molecular weight (Mw) of approximately 35,000.

[0092]

[0093] Example 7

[0094] A PtCo / Carbon particle catalyst (metal catalyst composite) was prepared in the same manner as in Example 1, except that 5 g of waste polystyrene (frozen food packaging box) used as product packaging material was used instead of 5 g of polystyrene beads having a weight average molecular weight (Mw) of approximately 35,000.

[0095]

[0096] Example 8

[0097] A PtCo / Carbon particle catalyst (metal catalyst composite) was prepared in the same manner as in Example 1, except that 5 g of waste polystyrene (Samsung monitor packaging buffer) used as a product buffer was used instead of 5 g of polystyrene beads having a weight average molecular weight (Mw) of approximately 35,000.

[0098]

[0099] Example 9

[0100] A PtNi / Carbon particle catalyst (metal catalyst composite) was prepared in the same manner as in Example 1, except that the PtCo precursor mixture was prepared using Ni(NO3)2·6H2O instead of Co(NO3)2·6H2O.

[0101]

[0102] Comparative Example 1

[0103] A PtCo / Carbon particle catalyst (metal catalyst composite) was prepared in the same manner as in Example 1, except that 5 ml of formaldehyde dimethyl acetal was used.

[0104]

[0105] Comparative Example 2

[0106] A PtCo / Carbon particle catalyst (metal catalyst composite) was prepared in the same manner as Example 1, except that 1 ml of formaldehyde dimethyl acetal was used.

[0107]

[0108] Experimental Example 1 - Measurement of the average particle size of a metal catalyst composite

[0109] The average particle diameter (D50) of the metal catalyst complex manufactured according to Example 1 was measured, and the average particle diameter of the measured metal catalyst complex was measured to be 38.4±2.9 nm (see Fig. 1a).

[0110] In addition, the average particle diameter (D50) of the metal catalyst complex manufactured according to Example 5 was measured, and the average particle diameter of the measured metal catalyst complex was measured to be 42.2±.4.1 nm (see Fig. 1b).

[0111]

[0112] Experimental Example 2 - Half-cell Test

[0113] An electrochemical half-cell test was conducted on the metal catalyst composite manufactured according to Example 1, and the experimental results are shown in Fig. 2a.

[0114] An electrochemical half-cell test was conducted on the metal catalyst composite manufactured according to Example 5, and the experimental results are shown in Fig. 2b.

[0115] An electrochemical half-cell test was conducted on a commercial catalyst (Pt / Carbon), and the experimental results are shown in Fig. 2c. Here, the commercial catalyst (Pt / Carbon) used was Platinum on graphitized carbon (20% Pt on Vulcan XC72) purchased from Sigma-Aldrich.

[0116] Electrochemical half-cell tests were performed in a three-electrode cell with a CHI 760E potentiostat at 25°C. The working electrode was glassy carbon (Pine, area: 0.247 cm 2)) was a rotating ring disk electrode. The counter electrode was a coiled platinum wire, and the reference electrode was Ag / AgCl saturated with 3 M NaCl. All potentials of half-cell tests obtained by evolution and hydrogen oxidation in aH2-saturated 0.1 M HClO4 solution using a Pt rotating disk electrode are reported with respect to a reversible hydrogen electrode (RHE). The catalyst powder was mixed with deionized water, IPA, and 5 wt% Nafion ® and sonicated in an ultrasonic bath for 20 min. The catalyst ink was loaded onto the working electrode and dried. The catalyst was activated by repeating 50 cycles of CV from 0.05 to 1.0 VRHE in Ar-saturated 0.1 M HClO4 solution at 100 mV / s. Linear sweep voltammetry (LSV) results were collected between 0.05 VRHE and 1.1 VRHE in the anodic scan direction in O2-saturated 0.1 M HClO4 solution at 10 mV / s and 1600 rpm. The ORR mass and specific activity were estimated using the Koutecky-Levich equation at 0.9 VRHE from the LSV curves after iR correction.

[0117] Referring to FIG. 2a, it can be seen that the voltage behavior of the half-cell including the metal catalyst composite manufactured according to Example 1 is at an excellent level, and specifically, the catalyst mass activity is 2.2 A / mg. Pt By representing 0.44 A / mg, the US Department of Energy's 2025 catalyst mass activity target PtIt can be seen that the level is higher than that of the commercial catalyst. In addition, compared to Fig. 2c using a commercial catalyst (Pt content of 20 wt%), it can be seen that when the metal catalyst composite manufactured according to Example 1 is included, the catalytic mass activity is comparable to that of the commercial catalyst, even though the Pt content is 5 wt%.

[0118] Referring to FIG. 2b, it can be seen that the voltage behavior of the half-cell including the metal catalyst composite manufactured using waste polystyrene used as building insulation according to Example 5 is at an excellent level, and specifically, the catalyst mass activity is 3.6 A / mg. Pt By representing 0.44 A / mg, the US Department of Energy's 2025 catalyst mass activity target Pt It can be seen that the level is higher than that of the commercial catalyst. In addition, compared to Fig. 2c using a commercial catalyst (Pt content 20 wt%), it can be seen that in the case of including the metal catalyst composite manufactured according to Example 5, a catalytic mass activity equivalent to that of the commercial catalyst is shown even though waste polystyrene is used.

[0119]

[0120] Experimental Example 3 - Full-cell Test

[0121] Full-cell tests were conducted on MEA samples containing metal catalyst composites manufactured according to Examples 1 to 4 and Comparative Examples 1 and 2, and MEA samples containing commercial catalysts (Pt / Carbon). The experimental results are shown in Table 1 and Figures 3a and 3b below.

[0122] Full-cell tests were performed using a PEMFC station (HTS-05, Horizon Fuel Cell). At the cathode electrode, the Pt loading was 0.05 mg for Examples 1 to 4 and Comparative Examples 1 and 2. Pt / cm 2, 0.2 mg for commercial catalyst (Pt / Carbon) Pt / cm 2 The catalyst ink was directly sprayed onto the Nafion 211 membrane until it reached the active area of ​​the MEA of 5 cm 2 At the anode electrode, the Pt loading was 0.2 mg Pt / cm 2 Commercial Pt / Carbon (20 wt%) was used. The fuel cell temperature was maintained at 80°C, and H2 / Air flowed into the anode and cathode. The flow rate of H2 / Air was 200 sccm at atmospheric pressure.

[0123] Meanwhile, a full-cell test was conducted on samples including metal catalyst complexes manufactured according to Examples 5 to 8, and the experimental results are shown in Table 2, Fig. 3c, and Fig. 3d below.

[0124] At this time, H2 / O2 with a relative humidity of 100% flowed to the anode and cathode, and the flow rate of H2 / O2 at this time was the same as the full-cell test conditions for the samples according to Examples 1 to 4, except that it was 200 sccm at a back pressure of 1.5 bar.

[0125] Sample Power density (mW.cm -2 )Example 1468.7Example 2464.6Example 3448.4Example 4454.3Comparative Example 1409.5Comparative Example 2289.5Commercial Catalyst (Pt / Carbon) 460.5

[0126] Sample Power density (mW.cm -2 )Embodiment 5605.5Embodiment 6583.3Embodiment 7578.0Embodiment 8588.4Embodiment 9596.2

[0127] Referring to Table 1, Figures 3a and 3b, it can be confirmed that the metal catalyst composites according to Examples 1 to 4 exhibit significantly superior fuel cell performance compared to the metal catalyst composites according to Comparative Examples 1 and 2 in all current ranges. In particular, at 700 mA / cm 2 The maximum current density from the above to the high current section is Comparative Example 1 (409.5 mW / cm 2 ) at least 10.9% (Example 4, 454.3 mW / cm 2 ) up to 14.5% (Example 1, 468.7 mW / cm 2 ) and shows high fuel cell performance. In addition, it can be confirmed through the IV Curve (see Fig. 3b) that the metal catalyst composites according to the examples show superior voltage generation levels in all current sections compared to the metal catalyst composites according to Comparative Examples 1 and 2.

[0128] In addition, it can be confirmed that the full-cell including the metal catalyst composite according to Examples 1 to 4 exhibits equivalent or superior fuel cell performance compared to the commercial catalyst composite.

[0129] From this, it can be seen that when the crosslinking agent formaldehyde dimethyl acetal is used in the step of manufacturing a hyper-crosslinked product at 5 ml or less (Comparative Examples 1 and 2), the cell performance is significantly reduced. In addition, it can be seen that when the crosslinking agent formaldehyde dimethyl acetal is used in 10 ml or less (Examples 1 to 4), the cell performance is improved.

[0130] In addition, by comparing and examining the examples, it can be confirmed that the performance of the metal catalyst composite and membrane-electrode assembly is better when the weight average molecular weight (Mw) of polystyrene is 200,000 or less (Example 1 and Example 2).

[0131] Referring to Table 2, Figures 3c and 3d, it can be confirmed that the metal catalyst composites according to Examples 5 to 9 exhibit remarkably excellent fuel cell performance in all current ranges, despite the use of waste polystyrene materials. 700 mA / cm 2 Examining the maximum current density from the above to the high current range, Example 5 is 605.5 mW / cm 2 , Example 6 is 583.3 mW / cm 2 , Example 7 is 578.0 mW / cm 2 , Example 8 is 588.4 mW / cm 2 , Example 9 is 596.2 mW / cm 2 By indicating, it showed excellent fuel cell performance.

[0132]

[0133] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention.

Claims

1. The first step is to obtain a hyper-crosslinked product by dispersing a polystyrene series material in a first solvent and then hyper-crosslinking it. The second step of breaking down the hyper-crosslinked material, A third step of carbonizing the above-mentioned crushed hyper-crosslinked material to produce carbonized polystyrene particles, and A fourth step of producing a metal catalyst complex by dispersing the above carbonized polystyrene particles in a second solvent, mixing them with a precursor of a catalyst metal, and then reducing them. Including Method for preparing a metal catalyst complex.

2. In paragraph 1, The metal catalyst complex comprises the carbonized polystyrene particles and a catalyst layer positioned on the carbonized polystyrene particles, The above catalyst layer comprises the above catalyst metal. Method for preparing a metal catalyst complex.

3. In paragraph 1, A method for producing a metal catalyst complex, wherein the above catalyst metal comprises at least one metal selected from the group consisting of platinum (Pt), palladium (Pd), ruthenium (Ru), iridium (Ir), nickel (Ni), cobalt (Co), and iron (Fe).

4. In paragraph 3, A method for producing a metal catalyst complex, wherein the above catalyst metal is an alloy containing at least one metal selected from the group consisting of platinum (Pt), palladium (Pd), ruthenium (Ru), iridium (Ir), nickel (Ni), cobalt (Co), and iron (Fe).

5. In paragraph 1, The fourth step above is, A step of preparing a dispersion liquid by dispersing the above carbonized polystyrene particles in a second solvent, A step of adjusting the pH of the above dispersion and then raising the temperature, A step of adding a precursor solution containing a precursor of the catalyst metal to the dispersion and then stirring, and A step of producing the metal catalyst complex by reducing the precursor of the above catalyst metal. A method for producing a metal catalyst complex comprising:

6. In paragraph 5, A method for producing a metal catalyst complex, wherein the second solvent comprises ethylene glycol.

7. In paragraph 5, The step of adjusting the pH of the above dispersion and then increasing the temperature is as follows: A step of stirring the above dispersion at 40 to 60°C, A step of adjusting the pH of the dispersion by adding NaOH, and Step of raising the temperature to 100 to 120 ℃ A method for producing a metal catalyst complex comprising:

8. In paragraph 5, A method for producing a metal catalyst complex, wherein the step of producing the metal catalyst complex by reducing the precursor of the catalyst metal is performed at a temperature range of 400 to 800°C for 10 minutes to 2 hours.

9. In paragraph 1, The above first step is, A method for producing a metal catalyst complex, comprising dispersing a polystyrene series material in the first solvent, adding a crosslinking catalyst and a crosslinking agent, stirring, and then raising the temperature to produce the hyper-crosslinked product.

10. In paragraph 9, The above crosslinking catalyst is a method for producing a metal catalyst complex including one or more of FeCl3, FeCl3·6H2O, AlCl3, CoCl3, ZnCl3, or CrCl4.

11. In paragraph 10, A method for producing a metal catalyst complex, wherein the crosslinking agent comprises at least one of formaldehyde dimethyl acetal, trichloromethane, or carbon tetrachloride.

12. In paragraph 11, A method for producing a metal catalyst complex, wherein the first solvent comprises dichloroethane.

13. In paragraph 1, A method for producing a metal catalyst complex, wherein the average particle diameter of the metal catalyst complex is less than 50 nm.

14. In paragraph 1, A method for producing a metal catalyst composite comprising at least one of the polystyrene series materials, polystyrene granules, polystyrene beads, polystyrene flakes, expanded polystyrene (EPS), or expandable polystyrene.

15. In paragraph 1, The above polystyrene series material is a method for producing a metal catalyst composite including waste polystyrene.

16. A metal catalyst complex manufactured by the method for manufacturing a metal catalyst complex according to any one of claims 1 to 15.

17. Polymer electrolyte membrane, and An electrode positioned on one side or the other side of the polymer electrolyte membrane, and comprising a metal catalyst complex manufactured by the method for manufacturing a metal catalyst complex according to any one of claims 1 to 15. Including Membrane-electrode assembly.

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