Gradient-constructed PtCu alloy aerogel catalyst layer and application thereof in direct ethanol fuel cell
The PtCu alloy aerogel catalytic layer constructed through gradient solves the problems of limited reserves of precious metals and difficulty in recycling of Pt-based aerogel catalysts, realizes efficient catalytic ethanol electrooxidation reaction, improves anti-toxicity ability, and optimizes the performance of membrane electrodes.
Patent Information
- Application Number
- CN202510517160.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-23
- Publication Date
- 2025-07-18
AI Technical Summary
The existing Pt-based aerogel catalysts have problems such as limited reserves of precious metal platinum, expensive and difficult to recover, and it is difficult to achieve efficient catalytic and anti-toxicity in the electrooxidation reaction of ethanol.
The PtCu alloy aerogel catalytic layer constructed using a gradient was prepared by a one-step synthesis method, and a multi-layer structure was formed on the gas diffusion layer in step. The alloying of Pt and Cu was used to adjust the active site and inhibit the adsorption of intermediates to optimize the catalyst performance.
The catalytic activity and anti-toxicity of the catalyst are improved, the amount of precious metals is reduced, the life of the catalyst is extended, and the performance of the membrane electrode is optimized.
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Figure CN120341301A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of fuel cell aerogel nanomaterials, and particularly relates to a PtCu alloy aerogel catalytic layer with a gradient structure and application thereof in a direct ethanol fuel cell. Background Art
[0002] The ethanol electrooxidation reaction (EOR) is the anode reaction of ethanol fuel cells (DEFCs). In the anode reaction, ethanol is converted into water and carbon dioxide through electrochemical oxidation, while releasing a large number of electrons. Among many liquid fuel cells, ethanol has received extensive attention in the field of clean energy due to its high energy density (8.01kWh / kg), low toxicity, and environmental safety. It has great development prospects in the field of liquid fuel cells. Since EOR is a complex process involving multiple electrons and multiple intermediates, it is difficult to achieve complete oxidation to CO2 in the actual oxidation process. The intermediates acetaldehyde and acetic acid are relatively common, so it is extremely challenging to design catalysts.
[0003] The key point of catalyst design is to have both high activity promotion (CC bond cleavage) and anti-poisoning ability (inhibition of CO adsorption). x The formation of intermediates, porous and nanostructures have high specific surface area and strain effect, which can significantly improve the activity. Therefore, Pt-based aerogel catalysts have the advantages of high specific surface area and promoting CC bond breaking and become the preferred catalyst for EOR.
[0004] However, the existing Pt-based aerogel catalysts have the following problems: platinum is a precious metal with limited global reserves and uneven distribution, resulting in high raw material prices, which makes Pt-based aerogels relatively expensive; the recycling of multi-metal-doped Pt-based aerogels has always been a big problem. A high-performance, recyclable and reasonably priced catalyst for ethanol electro-oxidation reaction (EOR) urgently needs further research and development. Summary of the invention
[0005] The purpose of the present invention is to provide a gradient constructed PtCu alloy aerogel catalytic layer in view of the technical defects existing in the prior art.
[0006] The technical solution adopted to achieve the purpose of the present invention is:
[0007] A method for gradient construction of a PtCu alloy aerogel catalytic layer comprises the following steps:
[0008] Step 1, using a NaBH4 aqueous solution to prepare a PtCu aerogel alloy aerogel by a one-step synthesis method, and then dispersing it in a solvent to prepare a PtCu aerogel alloy aerogel solution with different concentrations;
[0009] Step 2: Load PtCu aerogel alloy aerogel solutions with different concentrations onto the gas diffusion layer step by step. Each concentration of PtCu aerogel alloy aerogel forms a catalytic layer, and finally a PtCu alloy aerogel catalytic layer with a multi-layer structure is obtained.
[0010] In the above technical solution, in Step 1, the concentration of the aqueous NaBH4 solution is 1M.
[0011] In the above technical solution, the solvent in Step 1 is deionized water.
[0012] In the above technical solution, in Step 1, the preparation method of the PtCu aerogel alloy aerogel includes the following steps:
[0013] Mix equimolar amounts of chloroplatinic acid and copper chloride solution evenly, then add an aqueous solution of NaBH4, mix evenly, let it stand for sufficient reaction, and then filter and wash to obtain the PtCu alloy aerogel alloy aerogel.
[0014] In the above technical solution, the temperature for the sufficient standing reaction is 15 - 25°C, the reaction time is 7 - 9h, and during washing, ethanol and water are used for alternate washing.
[0015] In the above technical solution, in Step 2, the multi-layer structure is a two-layer structure.
[0016] In the above technical solution, in Step 1, disperse the PtCu aerogel alloy aerogel in a solvent, respectively prepare solutions of 10mg / ml and 50mg / ml, and then load them onto the gas diffusion layer in layers to obtain a PtCu alloy aerogel catalytic layer with a gradient structure.
[0017] On the other hand, the present invention also includes a PtCu alloy aerogel catalytic layer prepared by using the above method.
[0018] On the other hand, the present invention also includes the application of the PtCu alloy aerogel catalytic layer or the membrane electrode in a direct ethanol fuel cell.
[0019] On the other hand, the present invention also includes an anode liquid diffusion electrode of an ethanol fuel cell, which includes a gas diffusion layer and a PtCu alloy aerogel catalytic layer loaded on the gas diffusion layer.
[0020] On the other hand, a membrane electrode of an ethanol fuel cell includes the above anode liquid diffusion electrode, a proton exchange membrane, and a cathode gas diffusion electrode.
[0021] Compared with the prior art, the beneficial effects of the present invention are:
[0022] 1. The present invention optimizes the membrane electrode by constructing a gradient and adopting a multi-layer catalyst layer, resulting in a better performance of the membrane electrode. Moreover, when constructing the PtCu alloy aerogel catalyst layer with a gradient, the PtCu alloy aerogel reduced by a high multiple of sodium borohydride has its electrochemical properties further optimized.
[0023] 2. The bimetallic alloy (the alloy of Pt and Cu) can not only adjust the d-band center of the active site by the electron transfer between different metals, thereby optimizing the adsorption strength of reaction intermediates, but also inhibit the adsorption of toxic intermediates (such as CO) through the bimetallic synergistic effect to extend the catalyst life. The alloying of Pt and Cu causes the d-band center of Pt to shift downward, weakening the strong adsorption of intermediate products (such as CO*), reducing the poisoning risk, and improving the catalytic efficiency.
[0024] Attached drawings
[0025] Figure 1 is the macroscopic schematic diagram of Pt1Cu1 HSBAA.
[0026] Figure 2 is the transmission electron microscope (TEM) image of Pt1Cu1 HSBAA.
[0027] Figure 3 is the EDS-Mapping image of the Pt1Cu1 HSBAA region.
[0028] Figure 4 is the bar chart of the BET (Brunauer Emmet Teller) specific surface area of Pt1Cu1 HSBAA and Pt1Cu1 AA.
[0029] Figure 5 is the XRD pattern of Pt1Cu1 HSBAA and Pt1Cu1 AA.
[0030] Figure 6 is the result graph of cyclic voltammetry tests when Pt1Cu1 HSBAA, Pt1Cu1 AA, and Pt / C are respectively placed in a mixed solution of 0.5M H2SO4 + 1M C2H5OH in the potential range of -0.19 - 0.96V vs SCE and scanned at a scanning rate of 50mV / s.
[0031] Figure 7 is the test result of chronoamperometry tests when Pt1Cu1 HSBAA, Pt1Cu1 AA, and Pt / C are respectively placed in a mixed solution of 0.5M H2SO4 + 1M C2H5OH at a potential of 0.7V vs SCE.
[0032] Figure 8It is a comparison chart of the ethanol electro-oxidation performance of Pt1Cu1 HSBAA, Pt1Cu1 AA, and Pt / C.
[0033] Figure 9 It is the anode performance chart of Pt1Cu1 50mg / ml - 10mg / ml, Pt1Cu1 10mg / ml - 50mg / ml, Pt1Cu1 50mg / ml, Pt1Cu1 10mg / ml, and Pt / C for direct ethanol fuel cells. Specific Embodiments
[0034] The present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0035] Example 1
[0036] Using NaBH4 as a reducing agent, a surfactant-free catalyst PtCu aerogel alloy aerogel PtCu HSBAA was synthesized by a one-step method. The specific preparation method is as follows:
[0037] First, add chloroplatinic acid and copper chloride solution with a molar ratio of 1:1 to a round-bottom flask, then magnetically stir at 800 rpm for 30 min. Quickly add 2 ml of an aqueous solution of 1 M NaBH4 freshly prepared to the round-bottom flask, continue stirring for 1 min, then transfer it to a 20 °C constant temperature water bath and let it stand for 8 h. Finally, after washing with water and ethanol alternately 3 times, freeze the sample in liquid nitrogen for 1 min and then put it into a vacuum dryer. After the sample is dried, take it out to obtain PtCu aerogel alloy aerogel, denoted as Pt1Cu1 HSBAA.
[0038] Characterize the Pt1Cu1 HSBAA obtained in Example 1, as Figure 1 is the macroscopic schematic diagram of Pt1Cu1 HSBAA. Figure 2 is the transmission electron microscope (TEM) image of Pt1Cu1 HSBAA. From Figure 2 it can be seen that Pt1Cu1 HSBAA has a typical three-dimensional porous structure, where the extended ultrathin aerogels are interconnected. Figure 3 is the EDS-Mapping image of the Pt1Cu1 HSBAA region. Figure 3 is the elemental distribution map of Pt1Cu1 HSBAA at a scale of 10 nm by high-resolution transmission electron microscopy (HRTEM). It can be seen that the elemental distribution is very uniform, indicating that the material structure is very stable.
[0039] Comparative Example 1
[0040] Using the same method as in Example 1, except that the aqueous solution concentration of NaBH4 is 0.11 M, PtCu aerogel alloy aerogel was prepared and denoted as Pt1Cu1 AA.
[0041] As Figure 4 can be seen, Pt1Cu1 HSBAA and Pt1Cu1 AA have different porosities. The porosity of Pt1Cu1 HSBAA is 39.8 m 2 / g, and the porosity of Pt1Cu1 AA is 63.8 m 2 / g. The porosity of Pt1Cu1 HSBAA is lower.
[0042] Figure 5 are the XRD patterns of Pt1Cu1 HSBAA and Pt1Cu1 AA before EOR. The peak shape of Pt1Cu1 HSBAA is sharp, with higher intensity, and its crystallinity is better than that of Pt1Cu1 AA. The peak width of Pt1Cu1 AA is slightly wider, possibly because the crystal grains are smaller or there is a trace of lattice distortion.
[0043] As Figures 6 - 7 , the electrochemical performances of Pt1Cu1 HSBAA obtained in Example 1, Pt1Cu1 AA obtained in Comparative Example 1, and commercial Pt / C (Shanghai Hesen Electric Co., Ltd.) were tested using a three-electrode system (CS 310M electrochemical workstation). During the test, they were respectively dissolved in n-propanol and dropped onto a glassy carbon electrode with a diameter of 4 mm in the three-electrode system as the working electrode, a saturated calomel electrode (SCE) as the reference electrode, and a carbon plate as the counter electrode. The working electrodes were respectively placed in a mixed solution of 0.5 M H2SO4 + 1 M C2H5OH (the same test conditions below) in the potential range of -0.19 - 0.96 V vs SCE, and cyclic voltammetry tests were carried out at a scanning rate of 50 mV / s. The test results are as Figure 6 shown. Figure 6 is the cyclic voltammogram of ethanol electrooxidation of three catalysts, Pt1Cu1 HSBAA, Pt1Cu1 AA, and commercial Pt / C, in a nitrogen-saturated 0.5 M H2SO4 + 1 M C2H5OH solution. It can be clearly observed that the oxidation peak potential of Pt1Cu1 HSBAA is lower, indicating that this catalyst can initiate EOR at a relatively low potential, with more obvious kinetic advantages and a lower reaction energy barrier. The oxidation peak current of Pt1Cu1 HSBAA is the highest, and its mass activity (MA) is 1.71 A·mg Pt -1 , while the mass activities (MA) of Pt1Cu1 AA and commercial Pt / C catalysts are 1.47 A·mg Pt -1 and 0.49 A·mgPt -1 , it can be seen that Pt1Cu1 HSBAA has the best catalytic activity. The ratio of the reverse scan current to the forward peak current (i.e., j = Ib / If, where Ib is the reverse scan current and If is the forward peak current) reflects the anti-poisoning ability of the catalyst. The j value of Pt1Cu1 HSBAA reaches 0.9, which is significantly higher than 0.83 of Pt / C, indicating that its surface is less poisoned by CO adsorption. The j value of Pt1Cu1 AA is 0.89, which is also better than Pt / C.
[0044] Pt1Cu1 HSBAA obtained in Example 1, Pt1Cu1 AA obtained in Comparative Example 1, and commercial Pt / C (Shanghai Hesen Electric Co., Ltd.) were placed in a mixed solution of 0.5 M H2SO4 + 1 M C2H5OH (the same test conditions), and tested by chronoamperometry in the potential range of 0.7 V vs SCE. The test results are as Figure 7 . Figure 7 is the 1800S stability test of three catalysts, Pt1Cu1 HSBAA, Pt1Cu1 AA, and commercial Pt / C, at 0.7 V vs. SCE. After the stability test, Pt1Cu1 HSBAA still maintained 58.8% relative to the initial MA, while Pt1Cu1 AA and commercial Pt / C maintained 22.6% and 7% relative to the initial MA after the stability test. The stability of Pt1Cu1 HSBAA indicates that its current decay rate is relatively low, and the current is still greater than 50% of the initial value after 1800S, indicating that there are still many active sites on the catalyst, and a large number of active sites are not covered. The current decayed by 12.5% during the 1000S from 800S to 1800S, and it remained stable for a long time, in a stable plateau period, indicating that the material has good anti-deactivation ability. On the contrary, the decay rates of Pt1Cu1 AA and commercial Pt / C catalysts are relatively large, and a large number of active sites of the materials are lost. Through long-term I-T tests, no stepwise decline or large fluctuations were found in the three materials, indicating that there is no corresponding particle shedding of active sites or in-situ reconstruction on the material surface
[0045] Pt1Cu1 HSBAA obtained in Example 1, Pt1Cu1 AA obtained in Comparative Example 1, and commercial Pt / C were used as catalysts to fabricate membrane electrode assemblies (MEAs) respectively. The specific steps are as follows:
[0046] Prepare the anode liquid diffusion electrode: Mix 9 mg of the catalyst (Pt1Cu1 HSBAA, Pt1Cu1 AA, or commercial Pt / C), 1 mg of Nafion (5 wt%), and glycerol to prepare the catalyst ink, and obtain a 1×1 cm by spraying the catalyst ink on a commercial gas diffusion layer (Miolitech Co., Ltd.) 2Active area. Ensure that the anode catalyst loading is 2 mg Pt·cm -2 .
[0047] Prepare the cathode gas diffusion electrode: Use commercial 20 wt% Pt / C (Shanghai Hesen Electric Co., Ltd.) as the catalyst, with a loading of 2 mg·cm -2 .
[0048] Prepare the membrane electrode assembly: Combine the anode liquid diffusion electrode, proton exchange membrane, and the cathode gas diffusion electrode in sequence to form a sandwich structure. At a temperature of 130 °C and a pressure of 0.3 MPa, hot press for three minutes to obtain the membrane electrode assembly. The completed MEA is placed between two graphite plates with serpentine flow fields and matched with gaskets to ensure a compression ratio of 20 - 30%, and use a torque wrench to clamp diagonally.
[0049] Conduct the performance test of the single cell. Here, use an IT 8511A+ electronic load. The temperature of the membrane electrode fixture is 65 °C, and the flow rate of cathode oxygen is controlled at 200 mL·min -1 , and the flow rate of anode fuel is controlled at 2 mL·min -1 . Under this condition, obtain the stable polarization curve and power density curve. The results are as Figure 8 shown. The mass activity of Pt1Cu1 HSBAA is 1.71 A·mg Pt -1 , and the mass activity of Pt1Cu1 AA is 1.46 A·mg Pt -1 . It shows that the intrinsic activities (SA) of Pt1Cu1 HSBAA, Pt1Cu1 AA, and commercial Pt / C catalyst are 5.29 mA·cm -2 , 3.27 mA·cm -2 , 0.7 mA·cm -2 respectively. The SA of the material refers to the inherent catalytic ability of the material itself, reflecting the catalytic efficiency per active site or per unit surface area. It can be seen that the SA of Pt1Cu1 HSBAA is 7.5 times that of commercial Pt / C. Apply PtCu aerogels with different porosities to the anode of a direct ethanol fuel cell. The peak power of the ethanol fuel cell anode of Pt1Cu1HSBAA is 6.6 mw / cm 2 , and the peak power of the ethanol fuel cell anode of Pt1Cu1 AA is 4.6 mw / cm 2 . Since the peak power of Pt1Cu1 HSBAA is higher, Pt1Cu1 HSBAA is used for further optimization of the membrane electrode assembly subsequently.
[0050] Example 2
[0051] Based on the Pt1Cu1 HSBAA gradient prepared in Example 1, a PtCu alloy aerogel catalytic layer was constructed, and the specific method is as follows:
[0052] Dissolve Pt1Cu1 HSBAA in a n-propanol solution to prepare two kinds of inks with concentrations of 50 mg / ml and 10 mg / ml respectively. First, coat the 10 mg / ml ink on the gas diffusion layer to form an inner catalytic layer. After it dries, coat the 50 mg / ml ink on the inner catalytic layer. After it dries, an outer catalytic layer is formed to obtain an anode liquid diffusion electrode. Thus, when assembling the MEA, the outer catalytic layer formed by coating 50 mg / ml of Pt1Cu1 HSBAA is on the side close to the proton exchange membrane.
[0053] Combine the anode liquid diffusion electrode, the proton exchange membrane, and the cathode gas diffusion electrode (using commercial 20 wt% Pt / C as the catalyst) in sequence to form a sandwich structure. At a temperature of 130 °C and a pressure of 0.3 MPa, hot press for three minutes to obtain a membrane electrode, and prepare a membrane electrode (MEA) with a Pt1Cu1 50 mg / ml - 10 mg / ml catalytic layer.
[0054] Example 3
[0055] Based on the Pt1Cu1 HSBAA gradient prepared in Example 1, a PtCu alloy aerogel catalytic layer was constructed, and the specific method is as follows:
[0056] Dissolve Pt1Cu1 HSBAA in a n-propanol solution to prepare two kinds of inks with concentrations of 50 mg / ml and 10 mg / ml respectively. First, coat the 50 mg / ml ink on the gas diffusion layer to form an inner catalytic layer. After it dries, coat the 10 mg / ml ink on the inner catalytic layer. After it dries, an outer catalytic layer is formed to obtain an anode liquid diffusion electrode. Thus, when assembling the MEA, the outer catalytic layer formed by coating 10 mg / ml of Pt1Cu1 HSBAA is on the side close to the proton exchange membrane.
[0057] Combine the anode liquid diffusion electrode, the proton exchange membrane, and the cathode gas diffusion electrode (using commercial 20 wt% Pt / C as the catalyst) in sequence to form a sandwich structure. At a temperature of 130 °C and a pressure of 0.3 MPa, hot press for three minutes to obtain a membrane electrode, and prepare a membrane electrode (MEA) with a Pt1Cu1 10 mg / ml - 50 mg / ml catalytic layer.
[0058] The noble metal Pt loadings of Pt1Cu1 HSBAA in the inner catalytic layer and the outer catalytic layer in Example 2 and Example 3 are the same.
[0059] Comparative Example 2
[0060] Based on the Pt1Cu1 HSBAA prepared in Example 1, a PtCu alloy aerogel catalytic layer was constructed, and the specific method is as follows:
[0061] Dissolve Pt1Cu1 HSBAA in a n-propanol solution to prepare a 50 mg / ml solution, coat it on the gas diffusion layer, and after the solvent dries, a single catalytic layer is formed to obtain an anodic liquid diffusion electrode.
[0062] The anodic liquid diffusion electrode, proton exchange membrane, and cathodic gas diffusion electrode (using commercial 20 wt% Pt / C as the catalyst) were sequentially combined into a sandwich structure. At a temperature of 130 °C and a pressure of 0.3 MPa, hot pressing for three minutes gives a membrane electrode, and a membrane electrode (MEA) with a Pt1Cu1 50 mg / ml catalytic layer is prepared.
[0063] The loading of Pt1Cu1 HSBAA in the single catalytic layer of Comparative Example 2 is the same as the sum of the loadings of Pt1Cu1 HSBAA in the inner and outer catalytic layers of Example 3.
[0064] Comparative Example 3
[0065] Based on the Pt1Cu1 HSBAA prepared in Example 1, a PtCu alloy aerogel catalytic layer was constructed, and the specific method is as follows:
[0066] Dissolve Pt1Cu1 HSBAA in a n-propanol solution to prepare a 10 mg / ml solution, coat it on the gas diffusion layer, and after the solvent dries, a single catalytic layer is formed to obtain an anodic liquid diffusion electrode.
[0067] The anodic liquid diffusion electrode, proton exchange membrane, and cathodic gas diffusion electrode (using commercial 20 wt% Pt / C as the catalyst) were sequentially combined into a sandwich structure. At a temperature of 130 °C and a pressure of 0.3 MPa, hot pressing for three minutes gives a membrane electrode, and a membrane electrode (MEA) with a Pt1Cu1 10 mg / ml catalytic layer is prepared.
[0068] The loading of Pt1Cu1 HSBAA in the single catalytic layer of Comparative Example 3 is the same as the sum of the loadings of Pt1Cu1 HSBAA in the inner and outer catalytic layers of Example 3.
[0069] Comparative Example 4
[0070] Based on commercial Pt / C, a Pt / C catalytic layer was constructed, and the specific method is as follows:
[0071] Dissolve Pt / C in a n-propanol solution to prepare a 10 mg / ml solution, coat it on the gas diffusion layer, and after the solvent dries, a single catalytic layer is formed to obtain an anodic liquid diffusion electrode.
[0072] The anodic liquid diffusion electrode, proton exchange membrane, and cathodic gas diffusion electrode (using commercial 20 wt% Pt / C as the catalyst) were successively combined into a sandwich structure. At a temperature of 130 °C and a pressure of 0.3 MPa, hot pressing was performed for three minutes to obtain a membrane electrode, and a membrane electrode with a Pt / C catalytic layer (MEA) was prepared.
[0073] The Pt / C loading in the single catalytic layer of Comparative Example 4 was the same as the Pt loading of Pt1Cu1HSBAA in the inner and outer catalytic layers of Example 3, ensuring that the noble metal Pt loading was the same.
[0074] As Figure 8 shown, when comparing Example 2 - Example 3 and Comparative Example - Comparative Example 4, the polarization curve of the MEA with a double-layer catalytic layer was significantly superior. For the design of the catalytic layer (CL), a double-layer CL was adopted to give full play to the advantages of the catalysts in different layers. Pt1Cu1 HSBAA was configured into two concentrations of 50 mg / ml and 10 mg / ml respectively. The side close to the proton exchange membrane was used to prepare a membrane electrode with a Pt1Cu1 50 mg / ml - 10 mg / ml catalytic layer, and vice versa, the side close to the proton exchange membrane was used to prepare a membrane electrode with a Pt1Cu1 10 mg / ml - 50 mg / ml catalytic layer; it led the MEA with a single-layer catalytic layer in both the low current density region and the medium-high current density region. Figure 8 It can be seen that the open circuit voltages of Pt1Cu1 50 mg / ml - 10 mg / ml, Pt1Cu1 10 mg / ml - 50 mg / ml, Pt / C, Pt1Cu1 10 mg / ml, and Pt1Cu1 50 mg / ml were 0.583 V, 0.634 V, 0.396 V, 0.608 V, and 0.595 V respectively. The open circuit voltage was the potential difference between the ethanol oxidation reaction (EOR) and the oxygen reduction reaction (ORR) at the thermodynamic equilibrium state. A higher open circuit voltage meant higher activity and better performance of the MEA. The corresponding maximum power densities of these five MEAs were 9.4 mW / cm 2 、7.7 mW / cm 2 、3.3 mW / cm 2 、6.6 mW / cm 2 、4.9 mW / cm 2, the maximum power density is the most explicit indicator for measuring the performance of MEA. The performance of Pt1Cu1 50mg / ml-10mg / ml is increased by 42% and 91% respectively compared with Pt1Cu1 10mg / ml and Pt1Cu1 50mg / ml, and it is 2.84 times that of commercial Pt / C, which proves the superiority of the double-layer catalyst layer in the preparation of membrane electrode. At the same time, the MEA of Pt1Cu1 10mg / ml-50mg / ml has obvious advantages in the activation polarization region, probably due to the lower charge transfer resistance. The advantages of the MEA prepared by Pt1Cu1 50mg / ml-10mg / ml are more obvious in the ohmic polarization region and the concentration polarization region, which directly leads to its maximum power density. This reason may be due to the more advantageous ethanol fuel conduction of its catalyst layer in the concentration polarization region.
[0075] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.
Claims
1. A method for constructing a gradient PtCu alloy aerogel catalytic layer, characterized in that, It includes the following steps: Step 1: Prepare PtCu aerogel alloy aerogel by one-step synthesis method using aqueous NaBH4 solution, and then disperse it in a solvent to prepare PtCu aerogel alloy aerogel solutions with different concentrations. Step 2: Load the PtCu aerogel alloy aerogel solutions with different concentrations on the gas diffusion layer step by step. Each concentration of PtCu aerogel alloy aerogel forms a catalytic layer, and finally a PtCu alloy aerogel catalytic layer with a multi-layer structure is obtained.
2. The method according to claim 1, characterized in that In step 1, the concentration of the aqueous NaBH4 solution is 1M. Preferably, the solvent in step 1 is deionized water.
3. The method according to claim 1, wherein In step 1, the preparation method of the PtCu aerogel alloy aerogel includes the following steps: Mix equimolar amounts of chloroplatinic acid and copper chloride solution evenly, add an aqueous solution of NaBH4, mix evenly, let it stand for sufficient reaction, and then filter and wash to obtain PtCu alloy aerogel alloy aerogel.
4. The method according to claim 3, wherein The temperature for the sufficient standing reaction is 15 - 25°C, the reaction time is 7 - 9h, and ethanol and water are used alternately for washing during washing.
5. The method according to claim 1, characterized in that, In step 2, the multi-layer structure is a two-layer structure.
6. The method according to claim 5, characterized in that, In step 1, the PtCu aerogel alloy aerogel is dispersed in a solvent to prepare solutions of 10mg / ml and 50mg / ml respectively, and then layered on the gas diffusion layer to obtain a PtCu alloy aerogel catalytic layer with gradient construction.
7. A PtCu alloy aerogel catalytic layer prepared by using the method according to any one of claims 1 to 6.
8. Application of the PtCu alloy aerogel catalytic layer according to claim 7 in the membrane electrode of a direct ethanol fuel cell.
9. An anode liquid diffusion electrode of an ethanol fuel cell, characterized in that, It includes a gas diffusion layer and the PtCu alloy aerogel catalytic layer according to claim 7 loaded on the gas diffusion layer.
10. A membrane electrode of an ethanol fuel cell, characterized in that, It includes the anode liquid diffusion electrode, proton exchange membrane and cathode gas diffusion electrode according to claim 9.