Amorphous rare earth metal oxide coupled low-platinum-based catalyst as well as preparation method and application thereof
By preparing amorphous Gd2O3/C and Pt-Gd2O3/C catalysts, the problems of slow HOR kinetics and CO poisoning in anion exchange membrane fuel cells under alkaline conditions were solved, and catalysts with high activity, stability and low cost were achieved, thereby improving the performance of fuel cells.
Patent Information
- Application Number
- CN202510890108.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-30
- Publication Date
- 2025-11-18
AI Technical Summary
Existing anion exchange membrane fuel cells exhibit slow kinetics in the hydrogen oxidation reaction (HOR) under alkaline conditions. Traditional platinum-based catalysts are susceptible to CO poisoning and are also costly, which hinders their application and commercialization.
Amorphous Gd₂O₃/C and Pt-Gd₂O₃/C catalysts were prepared using a wet chemical-carbothermal method. By uniformly loading amorphous rare earth metal oxides and Pt nanoparticles onto a carbon black support, the electronic structure was adjusted to improve catalytic activity and stability.
A high-activity, stable, and CO-poisoning-resistant HOR catalyst was developed under alkaline conditions, improving the power density and overall performance of anion exchange membrane fuel cells.
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Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the field of anion exchange membrane fuel cells, and relates to an amorphous rare earth metal oxide coupled low platinum-based catalyst and a preparation method and application thereof. BACKGROUND
[0002] With the continuous development and consumption of fossil fuels, various environmental problems have come one after another. Air pollution, global warming, acid rain pollution and water body enrichment. Therefore, the importance of developing zero-emission and special energy density carbon alternatives must be taken seriously. At present, anion exchange membrane fuel cells (AEMFC) with high energy conversion efficiency are considered to be the next generation of hydrogen economy devices. Similarly, due to the high theoretical energy density, AEMFC can solve the problem of endurance anxiety at one time. However, even if platinum is used at the anode electrode, the reaction kinetics is significantly slower, which seriously affects the application of AEMFC. More critically, the high hydrogen oxidation reaction (HOR) kinetics under alkaline electrolyte is two to three orders of magnitude slower than the reaction in acidic medium. Therefore, finding and designing a high-performance, low-cost and HOR active HOR catalyst in alkaline electrolyte is a prerequisite for the successful commercialization of AEMFC technology. Previous studies have suggested that adsorbed hydrogen (H ad ) and adsorbed hydroxyl (OH ad ) both play an important role in the alkaline HOR mechanism, so hydrogen binding energy (HBE) and hydroxyl binding energy (OHBE) are considered as characteristic descriptors for analyzing HOR activity.
[0003] At present, platinum-based materials are widely used and have good catalytic activity as HOR electrocatalysts under alkaline conditions. The current bottleneck of anion exchange membrane fuel cells, the HOR process, is 2-3 orders of magnitude lower than under acidic conditions. Therefore, developing low-cost and high-activity catalysts has become the mainstream of current research.
[0004] To improve the metal activity, the activity of the catalyst is improved by the synergistic effect between the carrier and the metal. However, trace amounts of CO in hydrogen (even as low as 10 ppm) will adsorb on the platinum surface, hindering the active site. If the CO concentration is too high (such as 20,000 ppm), the traditional platinum-based catalyst will not be able to operate stably. It is very necessary to achieve high-performance HOR by changing the electronic structure of Pt, so as to carry out effective modulation strategy to obtain CO poisoning resistance performance. Since the electronic structure of 3d / 4d transition metal can be modulated by other d / p / f metal or non-metal dopant, therefore, electronic modulation is an important strategy to adjust the HOR activity of Pt, so as to produce spin-orbit coupling to activate the activity and stability of the metal active site. For example, Wei et al. explored the HOR catalytic process of Ir / O, Ir / Mo and Ir / MoO2, and found through DFT calculation that the surface electronic structure of the catalyst can be well regulated by constructing different interface chemical bonds to affect the catalytic activity. Due to the low degree of localization of interface electrons, Ir / O−MoO2 transfers charges from the surface to the interface through the interface Ir−O bond, thereby reducing the surface d-band center, which makes it weak to the adsorption of H* and OH*, and shows high theoretical activity. While Ir / Mo-MoO2 is just the opposite, showing low HOR theoretical activity. In addition to the synergistic effect between the carrier and the metal, recent studies have found that single-atom metals can also regulate the activity of the catalyst. Zheng et al. proposed a single-atom Mo modified Pt catalyst supported on N-doped C. This single-atom doped Pt catalyst greatly improves the catalytic activity and exhibits strong CO poisoning resistance. Compared with d / p orbitals, electrons on f orbitals are usually difficult to form covalent bonds directly, but due to the sufficient electronic transfer flexibility of 4f state, it is easier to contribute electrons and provide more electrons to solidify the covalent bond. For 4f energy level, rare earth (RE) elements typically benefit from unique valence 4f n−1 5d 1 6s 2 or 4f n 6s 2 electron configuration and the shielding effect of 5s and 5p electrons. Considering the strong spin-orbit coupling effect and the suitable 4f band position relative to the Fermi energy (E f ), the introduction of rare earth elements with 4f valence orbitals optimizes the electronic distribution of TM electrocatalytic active centers. At the same time, the construction of RE-O-TM skeleton induced by RE may be beneficial to achieve the conservation of TM-O covalence, and at the same time, the higher RE-4f state provides the required electrons for its catalytic process. For example, gadolinium (Gd) has a unique 4f 7 5d 1 6s 2Valence electron configuration. However, the detailed mechanism of 4f-induced HOR performance and the detailed influence of d-p-f interaction on HOR activity due to the complex valence orbital coupling are not clear and worthy of further elucidation. In-depth study in this regard will have the potential for a huge breakthrough in improving the mass activity, cycle stability and other aspects of HOR catalysts, and improving the power density in the application of anion exchange membrane fuel cell negative materials is also a strategy worthy of exploration. SUMMARY
[0005] In order to overcome the deficiencies of the prior art, the purpose of the present application is to provide an amorphous rare earth metal oxide coupled low platinum-based catalyst and its preparation method and application. The method of the present application is simple and universal, low in cost, and the prepared composite material is Pt / Gd2O3 supported on carbon black, which exhibits excellent activity and stability as a hydrogen oxidation electrocatalyst material, and exhibits good power density in anion exchange membrane fuel cell negative electrodes.
[0006] To solve the problems of the prior art, the technical scheme adopted by the present application is: The preparation method of an amorphous rare earth metal oxide coupled low platinum-based catalyst comprises the following steps: S1, preparing amorphous Gd2O3 / C The carbon black and GdCl3 are subjected to ultrasonic treatment in ethanol, water is added, and after heating and stirring for 8 h, centrifugal washing and drying are performed, and then oxidation is performed in a muffle furnace to obtain amorphous Gd2O3 / C, which is then washed with water and acetone in sequence and dried. S2, preparing Pt-Gd2O3 / C K2PtCl4 and Gd2O3 / C are dispersed in water and subjected to ultrasonic treatment for 1 h, evaporation is performed using a rotary evaporator, the residue is collected and dried overnight, and finally tube furnace calcination reaction is performed, followed by washing with water and acetone in sequence and drying, to obtain the low platinum-based catalyst Pt-Gd2O3 / C.
[0007] Preferably, in S1, the mass of GdCl3 is 50-300 mg, the mass of carbon black is 50-200 mg, the volume of ethanol is 10-100 mL, the volume of H2O is 5-20 mL, the ultrasonic machine working time is 10-20 min, the heating temperature is 75-80℃, and the heating time is 7-8 h.
[0008] Further preferably, in step S1, the mass of GdCl3 is 300 mg, the mass of carbon black is 200 mg, the volume of ethanol is 30 mL, and the volume of H2O is 5 mL.
[0009] Preferably, in step S1, the oxidation is performed at a heating rate of 1-4 ℃ / min to a temperature of 100-300 ℃, and the temperature is maintained for 1-2 h.
[0010] Preferably, the mass of K2PtCl4 in S2 is 10-50 mg, the mass of Gd2O3 / C is 50-200 mg, the volume of H2O is 50 mL, the working time of the ultrasonic machine is 50-60 min, and the temperature of the rotary evaporator is 50-60 DEG C.
[0011] Further preferably, the mass of K2PtCl4 in S2 is 24 mg, and the mass of Gd2O3 / C is 100 mg.
[0012] Preferably, the inert atmosphere in S2 is one of H2-Ar, Ar, N2 and N2 / H2 atmospheres.
[0013] Further preferably, the inert atmosphere in S2 is H2-Ar atmosphere.
[0014] Preferably, the carbon thermal treatment in S2 is heated to 200-600 DEG C at a heating rate of 5-10 DEG C / min, and the temperature is kept for 1-2 h.
[0015] An amorphous rare earth metal oxide coupled low platinum-based catalyst Pt-Gd2O3 / C prepared by any one of the above preparation methods, the low platinum-based catalyst Pt-Gd2O3 / C is a nanoparticle with an average particle size of 6.36 nm, and presents a coral-like carbon carrier structure, and the Pt nanoparticle and Gd2O3 are uniformly loaded on the carbon black carrier, wherein the Pt nanoparticle serves as a central active site, and the surrounding Gd2O3 has a regulating effect on the local electrons of the active center; the large specific surface area of the carbon black increases the number of exposed active sites, Gd2O3 itself does not have conductivity, but d-f The unique structure of the orbital coupling plays a role in dredging the charge transfer in the reaction process, and stabilizes the Pt nanoparticle so that it does not fall off, thereby improving the activity and stability of the Pt-Gd2O3 / C catalyst in the alkaline HOR.
[0016] The application of the amorphous rare earth metal oxide coupled low platinum-based catalyst prepared by the above preparation method in the alkaline hydrogen oxidation reaction.
[0017] The reaction principle of the application is as follows: Gadolinium chloride and potassium tetrachloroplatinate are used as metal sources, and carbon black is used as a carbon source, an amorphous Gd2O3 / C is prepared in advance by a wet chemical method, and a Pt-Gd2O3 / C nanocomposite is obtained by carbothermal reduction in an inert atmosphere. The Pt nanoparticle and the amorphous Gd2O3 are uniformly loaded on the carbon black carrier, the morphology is regular and uniform, and the obtained material has high hydrogen oxidation activity, excellent stability and CO poisoning resistance under alkaline conditions.
[0018] The catalyst of the present application is a coral-like carbon carrier structure, so that the catalyst material has a large specific surface area, and the exposure rate of active sites is increased, and the microporous structure of the carbon-based material can effectively promote the effective adsorption of reaction intermediates and active sites of the catalyst, which is beneficial to the reaction; by limiting and uniformly distributing the amorphous rare earth metal oxide Gd2O3 and Pt nanoparticles on the carbon carrier, the metal active sites in the catalytic process can be stably secured from falling off or agglomeration, thereby ensuring the catalytic stability; by reasonably modifying the Pt-based catalyst with the amorphous rare earth metal oxide, the amorphous Gd2O3 plays an important role in adjusting the electronic structure and optimizing the adsorption / desorption energy of the reaction intermediates, and the overall HOR activity of the catalyst is significantly improved.
[0019] Advantages: Compared with the prior art, the amorphous rare earth metal oxide coupled low platinum-based catalyst, the preparation method and application thereof have the following advantages: 1) A simple wet chemical-carbothermal method is used to prepare a Pt-Gd2O3 / C electrocatalyst with excellent electrochemical activity, high stability and good CO poisoning resistance; 2) The gadolinium chloride selected in the present application is cheap and easy to obtain, and the rare earth oxide has stable chemical properties; the method is simple, low in cost, easy to operate and can realize large-scale production; 3) The amorphous rare earth metal oxide coupled low platinum-based catalyst Pt-Gd2O3 / C catalyst has a regular morphology, and Pt and Gd2O3 are uniformly loaded on the carbon black carrier; the synergistic effect between Pt and Gd2O3 not only helps to stabilize the Pt nanoparticles, but also adjusts the electronic structure of Pt, optimizes the binding strength of Pt and H and OH, promotes the adsorption and desorption of reaction intermediates, and finally realizes the improvement of the HOR catalytic activity.
[0020] 4) The material prepared by the present application has the characteristics of large specific area, rich active sites, high intrinsic activity, excellent stability and good poisoning resistance, compared with conventional Pt-based materials, the prepared Pt-Gd2O3 / C has more excellent structural characteristics and component advantages, and is a very potential hydrogen oxidation electrocatalyst material, which shows good power density in anion exchange membrane fuel cells, and is expected to have wide application prospects in the future energy industry. BRIEF DESCRIPTION OF DRAWINGS
[0021] Figure 1 SEM spectrum of a rare earth metal oxide coupled platinum-based catalyst prepared in Example 1; Figure 2 TEM spectrum of a rare earth metal oxide coupled platinum-based catalyst prepared in Example 1; Figure 3XRD pattern of a rare earth metal oxide coupled platinum-based catalyst prepared in Example 1; Figure 4 Tafel curve of a rare earth metal oxide coupled platinum-based catalyst prepared in Example 1; Figure 5 Comparison of LSV curves of materials obtained in Example 1 and Comparative Examples 2 and 3 in the present application; Figure 6 Comparison of CO poisoning resistance test curves of materials obtained in Example 1 and Comparative Examples 2 and 3 in the present application; Figure 7 Fuel cell polarization curve and corresponding power density of the material obtained in Example 1 in the present application. DETAILED DESCRIPTION
[0022] The present application will be described in detail below with specific examples. The following examples will help those skilled in the art to further understand the present application, but do not limit the present application in any form. It should be noted that, for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made. These all belong to the protection scope of the present application. Example 1
[0023] A preparation method of an amorphous rare earth metal oxide coupled low platinum-based catalyst, comprising the following steps: 1) Preparation of amorphous Gd2O3 / C: 200 mg of carbon black and 300 mg of GdCl3 were ultrasonically treated in 30 mL of ethanol for 15 min, 5 mL of water was added, heated to 80 ℃ and stirred for 8 h, centrifuged, washed and dried, and then oxidized in a muffle furnace at a temperature increasing rate of 4 ℃ / min at 300 ℃ for 2 h to obtain amorphous Gd2O3 / C, which was washed with water and acetone in turn and then dried.
[0024] 2) Preparation of Pt-Gd2O3 / C: 24 mg of K2PtCl4 and 100 mg of amorphous Gd2O3 / C obtained in step 1) were dispersed in 50 mL of water and ultrasonically treated for 1 h, evaporated with a rotary evaporator at 60 ℃, the residue was collected and dried overnight, and finally calcined at 300 ℃ under H2-Ar atmosphere at a temperature increasing rate of 5 ℃ / min for 1 h, washed with water and acetone in turn and then dried to obtain Pt-Gd2O3 / C.
[0025] The amorphous rare earth metal oxide coupled low platinum-based catalyst Pt-Gd2O3 / C prepared in Example 1 was physically characterized by SEM, TEM, XRD and the like, and the results are shown in Figures 1-4 Figure 1 ) shows that the material is composed of nanoparticles with an average particle size of 3.06 nm. TEM pattern Figure 2 ) shows Pt nanoparticles and amorphous Gd2O3 supported on carbon support, which is consistent with the results of SEM. XRD pattern Figure 3 It can be seen that the diffraction peaks of the material are completely consistent with the standard card of Pt (JCPDS card, 04-0802), and there is no obvious Gd2O3 related diffraction peak, which is due to the amorphous state of the prepared Gd2O3, and the (002) crystal face corresponds to the diffraction peak of graphitized carbon.
[0026] Tafel curve Figure 4 ) shows that the material has a faster reaction kinetic rate, which is better than most alkaline hydrogen oxidation electrocatalyst materials.
[0027] The above results all show that the material has good application prospect as an alkaline hydrogen oxidation electrocatalyst material. Example 2
[0028] Except that the amount of GdCl3 in step 1 is changed to 75 mg, the rest is the same as example 1. Example 3
[0029] Except that the amount of K2PtCl4 in step 1 is changed to 36 mg, the rest is the same as example 1. Example 4
[0030] Except that the amount of oxidized carbon black in step 1 is changed to 100 mg, the rest is the same as example 1. Example 5
[0031] Except that the amount of ethanol in step 1 is changed to 40 mL, the rest is the same as example 1. Example 6
[0032] Except that the ultrasonic time in step 1 is changed to 20 min, the rest is the same as example 1. Example 7
[0033] Except that the amount of water in step 1 is changed to 10 mL, the rest is the same as example 1. Example 8
[0034] Except that the heating rate of oxidation in step 1 is changed to 3℃ / min, the rest is the same as example 1. Example 9
[0035] Except that the temperature of oxidation in step 1 is changed to 200℃, the rest is the same as example 1. Example 10
[0036] Except that the oxidation time in step 1 is changed to 3h, the rest is the same as example 1. Example 11
[0037] Except that the temperature ramping rate of the carbothermal treatment in Step 2 was changed to 10 °C / min, the rest was the same as Example 1. Example 12
[0038] Except that the temperature ramping rate of the carbothermal treatment in Step 2 was changed to 10 °C / min, the rest was the same as Example 1. Example 13
[0039] Except that the temperature ramping rate of the carbothermal treatment in Step 2 was changed to 10 °C / min, the rest was the same as Example 1. Example 14
[0040] Except that the temperature ramping rate of the carbothermal treatment in Step 2 was changed to 10 °C / min, the rest was the same as Example 1.
[0041] Comparative Example 1 The difference from Example 1 is only that only a single metal salt K2PtCl4 was used, and the rest of the implementation conditions were unchanged.
[0042] Comparative Example 2 The difference from Example 1 is only that only a single metal salt GdCl3 was used, and the rest of the implementation conditions were unchanged.
[0043] The materials of Example 1, Comparative Examples 1-2 were tested for basic hydroxyl reaction, and electrochemical measurement was carried out using a CHI660E workstation in a three-electrode system in a 0.1 M KOH solution, with a graphite rod and a mercury / mercury oxide electrode as the counter electrode and reference electrode, respectively. The specific steps are as follows: After mixing 5 mg of catalyst with 100 μL of Nafion (5 wt. %), 300 μL of deionized water and 600 μL of ethanol were added and ultrasonically treated for 30 min to obtain a catalyst ink. 10 μL of the catalyst ink was uniformly dropped on a glassy carbon electrode with an area of 0.196 cm 2 , and after natural drying, it was used as a working electrode.
[0044] In H2-saturated electrolyte, the scan rate was 5 mV s-1, the scan rate was 0.02-1.02 V or 0.1-0.5 V (vs. RHE), the scan rate was 1600 rpm, and the LSV curve was obtained on the RDE, and the results are shown in Figure 5 From the figure, it can be seen that the kinetic current density of Pt-Gd2O3 / C is 39.36 mA cm -2, exhibited its superior current density, single metal Pt and Gd2O3 prepared by electrocatalytic material showed poor hydrogen oxidation performance of Pt-Gd2O3 / C composite material. The overall performance of the comparison showed the order of Pt-Gd2O3>Pt>Gd2O3.
[0045] CO stripping voltammetry measurements were performed in 0.1 M KOH solution. Before the test, pure N2 was input into the electrolyte to remove the air in the electrolyte. Then, the electrode was kept under bubbling CO gas at 0.1 V vs. RHE for 15 min, and then the electrolyte was purged with N2 for 30 min to completely remove CO in the solution, leaving only a layer of CO on the working electrode surface, and recording the CO stripping voltammetry from 0 V to 1.0 V (vs. RHE) at 20 mV s -1 The CO stripping voltammetry measurements were performed in 0.1 M KOH solution. Before the test, pure N2 was input into the electrolyte to remove the air in the electrolyte. Then, the electrode was kept under bubbling CO gas at 0.1 V vs. RHE for 15 min, and then the electrolyte was purged with N2 for 30 min to completely remove CO in the solution, leaving only a layer of CO on the working electrode surface, and recording the CO stripping voltammetry from 0 V to 1.0 V (vs. RHE) at 20 mV s Figure 6 As shown in the test results, Pt-Gd2O3 / C appeared CO oxidation peak at lower potential, indicating that the CO adsorbed on the surface of the catalyst was more easily oxidized and desorbed, further strengthening the CO tolerance of the catalyst, thus exhibiting the unique CO poisoning resistance advantage of Pt-Gd2O3 / C.
[0046] The above describes specific embodiments of the present application. It should be understood that the present application is not limited to the above specific embodiments, and those skilled in the art can make various modifications or modifications within the scope of the claims, which does not affect the essential content of the present application.
Claims
1. A method for preparing a low-platinum-based catalyst coupled with amorphous rare-earth metal oxides, characterized in that, Includes the following steps: S1. Preparation of amorphous Gd₂O₃ / C Carbon black and GdCl3 were ultrasonically treated in ethanol, water was added, and the mixture was heated and stirred for 8 h. After centrifugation, washing and drying, the mixture was oxidized in a muffle furnace to obtain amorphous Gd2O3 / C. The mixture was then washed with water and acetone in sequence and dried. S2, Preparation of Pt-Gd2O3 / C K2PtCl4 and Gd2O3 / C were dispersed in water and sonicated for 1 h. The mixture was then evaporated using a rotary evaporator. The residue was collected, dried overnight, and finally calcined in a tube furnace. After washing with water and acetone in sequence, the mixture was dried to obtain the low-platinum catalyst Pt-Gd2O3 / C.
2. The method for preparing an amorphous rare earth metal oxide coupled low-platinum-based catalyst according to claim 1, characterized in that, In S1, the mass of GdCl3 is 50-300 mg, the mass of carbon black is 50-200 mg, the volume of ethanol is 10-100 mL, the volume of H2O is 5-20 mL, the ultrasonic machine working time is 10-20 min, the heating temperature is 75-80 ℃, and the heating time is 7-8 h.
3. The method for preparing an amorphous rare earth metal oxide coupled low-platinum-based catalyst according to claim 1, characterized in that, In S1, oxidation is carried out by heating the temperature to 100-300 ℃ at a heating rate of 1-4 ℃ / min and holding it at that temperature for 1-3 h.
4. The method for preparing an amorphous rare earth metal oxide coupled low-platinum-based catalyst according to claim 1, characterized in that, The mass of K2PtCl4 in S2 is 10-50 mg, the mass of Gd2O3 / C is 50-200 mg, the volume of H2O is 50 mL, the ultrasonic machine working time is 50-60 min, and the rotary evaporator temperature is 50-60 ℃.
5. The method for preparing an amorphous rare earth metal oxide coupled low-platinum-based catalyst according to claim 1, characterized in that, In step S2, the inert atmosphere is one of H2-Ar, Ar, N2, and N2 / H2 atmosphere.
6. The method for preparing an amorphous rare earth metal oxide coupled low platinum-based catalyst according to claim 1, characterized in that, In step S2, the carbon heat treatment is carried out at a heating rate of 5-10 ℃ / min to a temperature of 200-600 ℃, and held at that temperature for 1-2 hours.
7. A low-platinum-based Pt-Gd2O3 / C catalyst coupled with an amorphous rare earth metal oxide, prepared by the preparation method according to any one of claims 1-6.
8. The low-platinum-based catalyst Pt-Gd₂O₃ / C coupled with amorphous rare earth metal oxides according to claim 7, characterized in that, The low-platinum-based catalyst Pt-Gd₂O₃ / C consists of nanoparticles with an average particle size of 6.36 nm, exhibiting a coral-like carbon support structure. Pt nanoparticles and Gd₂O₃ are uniformly loaded on a carbon black support. The Pt nanoparticles serve as central active sites, while the surrounding Gd₂O₃ modulates the local electrons of these active sites. The large specific surface area of the carbon black increases the number of exposed active sites. While Gd₂O₃ itself is not conductive, df The unique orbital coupling structure facilitates charge transfer during the reaction and stabilizes Pt nanoparticles to prevent them from falling off, thereby improving the activity and stability of the Pt-Gd2O3 / C catalyst in alkaline HOR.
9. The application of the Pt-Gd2O3 / C catalyst with gadolinium oxide nanomaterials as the support prepared by the preparation method according to claim 1 as an alkaline HOR catalyst.