Alkaline electrolytic water hydrogen production composite system of quaternized trifluoroacetophenone copolymerization non-porous membrane loaded high-activity cobalt-manganese oxygen vacancy catalyst

Abstract

The invention relates to the technical field of hydrogen production through electrolysis of water, in particular to a composite system based on a quaternized trifluoroacetophenone copolymerized nonporous membrane and a cobalt-manganese oxygen vacancy catalyst, the composite system comprises the quaternized trifluoroacetophenone copolymerized nonporous membrane and the cobalt-manganese oxygen vacancy catalyst, the catalyst is loaded on the surface of the membrane through hydrogen-bond interaction, and the loading capacity is 1.0-1.5 mg / cm < 2 >; the repeating unit structure of the non-porous membrane is-[C6H3 (CF3)-CO-C6H4-CH2-N < + > (CH3) 3. OH <->]-n, n is equal to 500 to 1000, and the content of quaternary ammonium groups is 1.2 to 1.8 mmol / g; the catalyst is spinel type Co < x > Mn < gamma > O < 4-delta >, x: y = 1: 1-3: 1, and oxygen vacancy concentration delta = 0.1-0.3. On the basis of copolymerization of trifluoroacetophenone and 4-vinyl benzyl chloride, a high-density quaternary ammonium group (1.2-1.8 mmol / g) is introduced through quaternization reaction, and high ionic conductivity (85 mS / cm) and low swelling ratio (lt) are both considered; and the problems of permeation and alkali-resistant degradation of the traditional membrane electrolyte are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen production by electrolysis of water, and in particular to a composite system based on a quaternized trifluoroacetophenone copolymer non-porous membrane and a cobalt-manganese oxygen vacancy catalyst, which is particularly suitable for a high-efficiency hydrogen production process by electrolysis of water in an alkaline environment. Background Art

[0002] Alkaline water electrolysis for hydrogen production, a key technology for sustainable energy conversion, faces a critical bottleneck: the performance limitations of the electrolyzer's core materials (ion exchange membranes and catalysts). Traditional quaternized polyether membranes, due to their insufficient hydrophobicity, swell as high as 15%-30% in alkaline electrolytes, leading to electrolyte cross-penetration and a drop in current efficiency below 70%. Furthermore, the quaternary ammonium groups are susceptible to OH-nucleophilic attack, resulting in a degradation rate exceeding 40% after 300 hours of operation at 80°C in 30% KOH, as disclosed in Patent No. CN113845217A. While cost-effective, cobalt-manganese composite oxide catalysts suffer from difficult-to-control surface oxygen vacancies (δ < 0.1) and weak binding to the membrane support, with a shedding rate exceeding 15% over 1000 hours of operation, resulting in an overpotential increase of more than 50 mV, as disclosed in Patent No. CN112721568B. Furthermore, the membrane-catalyst interface lacks effective interaction, resulting in high ion transport resistance (charge transfer resistance > 20 Ω), and the full water splitting voltage is limited to 100 mA / cm2. 2 The voltage generally exceeds 1.7V, which is much higher than the theoretical value of 1.23V.

[0003] Existing technologies, such as the "non-porous membrane-supported transition metal catalyst" disclosed in CN114083679A, do not address the regulation of membrane hydrophobicity by fluorine substituents, and the concentration of oxygen vacancies in the catalyst is not quantified. While the "quaternized aromatic polymer membrane" in US20230127891A1 improves alkali resistance, it does not address the interfacial synergy issue with the catalyst. Therefore, the development of a membrane material with low swelling and high alkali resistance, a catalyst with high oxygen vacancies and strong binding capacity, and a composite system combining the two has become an urgent technical challenge. Summary of the Invention

[0004] The present invention discloses a method for preparing a traditional Chinese medicine composition for preventing and treating stroke sequelae. The composition comprises Gastrodia elata, Eucommia ulmoides, Uncaria rhynchophylla, and Musk. The composition is prepared using modern nanotechnology to form clinically acceptable capsules. Its bioavailability is significantly superior to that of conventional methods. It is significantly effective in preventing and treating stroke sequelae.

[0005] A composite system for hydrogen production from alkaline water electrolysis using a quaternized trifluoroacetophenone copolymer nonporous membrane loaded with a highly active cobalt-manganese-oxygen vacancy catalyst comprises a quaternized trifluoroacetophenone copolymer nonporous membrane and a cobalt-manganese-oxygen vacancy catalyst. The catalyst is loaded on the membrane surface via hydrogen bonding, with a loading of 1.0-1.5 mg / cm 2The repeating unit structure of the non-porous membrane is -[C6H3(CF3)-CO-C6H4-CH2-N + (CH3)3·OH - ]- n ,

[0006]

[0007] Formula 1, wherein n in Formula 1 is 500-1000, and the quaternary ammonium group content is 1.2-1.8 mmol / g; the catalyst is spinel-type Co x Mn γ O 4- δ, x:y = 1:1-3:1, oxygen vacancy concentration δ = 0.1-0.3.

[0008] Furthermore, wherein: the left chain segment is a trifluoroacetophenone derivative structure:

[0009] -C6H3(CF3)-CO- (Formula 3), trifluoromethyl (-CF3) is a strong electron-withdrawing group, which inhibits the swelling of the membrane in alkaline solution (swelling rate <5%) through steric hindrance and hydrophobic interaction; the right chain segment is a quaternized structure -C6H4-CH2-N + (CH3)3·OH-, quaternary ammonium group (N + ) provides OH- conduction channels, forms hydrogen bonds (N...HO-) with oxygen vacancies on the catalyst surface, and enhances the interfacial bonding force; the degree of polymerization n = 500-1000 ensures the mechanical strength of the membrane.

[0010] Further, copolymerization reaction (trifluoroacetophenone and 4-vinylbenzyl chloride),

[0011] C6H3(CF3)CO-C6H4=CH2+CL-CH2-C6H4-CH=CH2→

[0012] [-C6H(CF3)CO-C6H4-CH2-CH(C6H4-CH4CL)-]

[0013] Furthermore, in the quaternized trifluoroacetophenone copolymer non-porous membrane, the trifluoroacetophenone chain segment accounts for 40%-60% (molar fraction), the membrane thickness is 50-80 μm, and the swelling rate in 1 mol / L KOH at 60° C. is less than 5%.

[0014] Furthermore, the average particle size of the cobalt manganese oxygen vacancy catalyst is 10-20 nm, and the characteristic peak of oxygen vacancy at 531.8 eV in the XPS characterization O1s spectrum accounts for 16%-22%.

[0015] A method for preparing the composite system comprises the following steps:

[0016] S1: Preparation of quaternized trifluoroacetophenone copolymer non-porous membrane: trifluoroacetophenone and 4-vinylbenzyl chloride are copolymerized to obtain a precursor, which is then cast into a membrane after quaternization reaction;

[0017] S2: Preparation of cobalt-manganese oxygen vacancy catalyst: co-precipitation of cobalt-manganese nitrate → hydrothermal reaction → calcination in Ar / H2 atmosphere;

[0018] S3: Constructing a composite system: The catalyst ultrasonic dispersion liquid is impregnated into the membrane surface and dried and fixed.

[0019] Furthermore, in step S1, the copolymerization reaction temperature is 70-90° C., the time is 5-8 hours, and the initiator is AIBN, and the amount used is 2%-3% of the total weight of the monomers.

[0020] Furthermore, in step S1, the quaternization reaction uses a trimethylamine aqueous solution (33%), a reaction temperature of 50-70° C., and a reaction time of 10-14 h.

[0021] Furthermore, in step S2, the hydrothermal reaction temperature is 160-200°C, and the time is 10-16 hours; the calcination temperature is 300-400°C, the Ar / H2 volume ratio is 8:1-10:1, and the time is 1-3 hours.

[0022] Furthermore, in step S3, the catalyst dispersion contains 0.1%-0.5% PVP dispersant, the ultrasonic power is 200-400W, and the time is 20-40 minutes.

[0023] Furthermore, the alkaline electrolyte is 1-3 mol / L KOH, the electrolysis temperature is 50-70°C, and the current density is 5-200 mA / cm 2 .

[0024] Furthermore, the composite system is at 10 mA / cm 2 The hydrogen evolution overpotential under current density is ≤135mV, and the 1000h operation stability retention rate is ≥96%.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. Based on the copolymerization of trifluoroacetophenone and 4-vinylbenzyl chloride, a high-density quaternary ammonium group (1.2-1.8mmol / g) is introduced through a quaternization reaction, which takes into account high ionic conductivity (85mS / cm) and low swelling rate (<5%), solving the problems of traditional membrane electrolyte penetration and alkali degradation resistance; regulating the spinel Co x Mn γThe oxygen vacancy concentration and particle size of O4-δ (10-20nm) are precisely controlled by Ar / H2 calcination, and the active site density is more than 2 times higher than that of traditional catalysts: the catalyst and the membrane are tightly bound by hydrogen bonding (N...HO-), and the interfacial charge transfer resistance is reduced to below 5Ω, 100mA / cm 2 The full water splitting voltage is as low as 1.55V, which is more than 10% lower than the traditional system; under the conditions of 1mol / LKOH and 60℃, 10mA / cm 2 The hydrogen evolution overpotential is ≤135mV, the 1000h operation stability retention rate is ≥96%, the membrane swelling rate is <3.1%, and the catalyst shedding rate is <2%. The comprehensive performance far exceeds the existing technology. DETAILED DESCRIPTION

[0027] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0028] Composite system composition: It is composed of quaternized trifluoroacetophenone copolymer non-porous membrane (matrix) and cobalt manganese oxygen vacancy catalyst (active component). The catalyst is loaded on the membrane surface through hydrogen bonding, with a loading capacity of 1.0-1.5 mg / cm 2 .

[0029] Quaternized trifluoroacetophenone copolymer non-porous membrane:

[0030] Structural formula: Repeating unit is [C6H3(CF3)-CO-C6H4-CH2-N + (CH3)3·OH - ]- n , wherein n=500-1000 (number average molecular weight 80,000-150,000 g / mol); the repeating unit structure of the quaternized trifluoroacetophenone copolymer non-porous membrane is as follows:

[0031]

[0032] Characteristics: Trifluoroacetophenone chain segments (-C6H3(CF3)-CO-) account for 40%-60% (molar fraction), quaternary ammonium group content is 1.2-1.8 mmol / g, film thickness is 50-80 μm, and swelling ratio in 1 mol / L KOH at 60°C is <5%. The trifluoroacetophenone monomer structure is as follows:

[0033]

[0034] Cobalt-manganese oxygen vacancy catalyst:

[0035] Chemical composition: spinel Co x Mn γ O 4- δ, x:y = 1:1-3:1, oxygen vacancy concentration δ = 0.1-0.3;

[0036] Structural characteristics: average particle size 10-20nm, XPS characterization of the oxygen vacancy characteristic peak at 531.8eV in the O1s spectrum accounts for 16%-22%.

[0037] Preparation method:

[0038] S1. Copolymerization: Trifluoroacetophenone and 4-vinylbenzyl chloride are reacted at 70-90°C (preferably 80°C) for 5-8h, and AIBN is used as the initiator (2%-3%). The molecular weight (M) is regulated by controlling the temperature and the amount of initiator. n =80,000-150,000 g / mol).

[0039] Quaternization reaction: 33% trimethylamine aqueous solution is reacted at 50-70° C. (preferably 60° C.) for 10-14 h to ensure that the quaternary ammonium group is fully introduced (content 1.2-1.8 mmol / g).

[0040] Cast film: DMF is used as solvent, 100 μm gap doctor blade casting, step drying (25℃→50℃→80℃), to ensure uniform film thickness (50-80 μm).

[0041] S2. Coprecipitation: Cobalt and manganese nitrates are mixed in proportion and the pH is adjusted to 8-9 to generate hydroxide precipitate.

[0042] Hydrothermal reaction: 160-200°C (preferably 180°C) for 10-16 hours to form precursor crystals.

[0043] Calcination: Calcination at 300-400° C. (preferably 350° C.) for 1-3 h in an Ar / H 2 (8:1-10:1, preferably 9:1) atmosphere (control the oxygen vacancy concentration δ=0.1-0.3).

[0044] S3. Catalyst dispersion: 0.1%-0.5% PVP is used as a dispersant, and ultrasonication is performed at 200-400W (preferably 300W) for 20-40 minutes to ensure that the particle size is 10-20nm.

[0045] Load fixation: After the membrane is immersed in the dispersion, it is vacuum dried at 60°C to ensure uniform loading (loading capacity 1.2 mg / cm 2 is optimal).

[0046] Membrane preparation: copolymerization of trifluoroacetophenone and 4-vinylbenzyl chloride → quaternization reaction → doctor blade casting;

[0047] Catalyst preparation: cobalt-manganese nitrate coprecipitation → hydrothermal reaction → calcination in Ar / H2 atmosphere (300-400℃);

[0048] Construction of composite system: catalyst ultrasonic dispersion liquid is impregnated into membrane surface - dried and fixed.

[0049] Example 1: Preparation of quaternized trifluoroacetophenone copolymer non-porous membrane

[0050] (1) Preparation of copolymer precursor: Under nitrogen protection, trifluoroacetophenone (TFAP, 10.0 g, 50 mmol) and 4-vinylbenzyl chloride (VBC, 8.2 g, 60 mmol) were dissolved in 100 mL of anhydrous DMF, and AIBN (0.4 g, 2.5 mmol) was added. The mixture was stirred at 80°C for 6 h (GPC monitoring showed Mn = 80,000 g / mol). The reaction solution was poured into 500 mL of ice methanol for precipitation. After filtration, the mixture was washed with methanol three times and dried in vacuo at 60°C for 12 h to obtain a white flocculent precursor (15.6 g, yield 82%). 1 HNMR (400 MHz, DMSO-d6): δ 7.8-8.2 (aromatic hydrogen, 6H), 6.7 (vinyl hydrogen, 2H), 4.5 (benzyl chloride-CH2Cl, 2H), 1.5-2.0 (main chain-CH2-, 4H).

[0051] (2) Quaternization reaction: The precursor (10.0 g) was dissolved in 100 mL of chloroform, and a 33% aqueous solution of trimethylamine (50 mL, 0.5 mol) was added dropwise at 60°C. The mixture was stirred for 12 h (TLC monitoring indicated the disappearance of the starting material). The reaction solution was dialyzed against deionized water (3500 Da cutoff) for 72 h and freeze-dried to obtain a quaternized copolymer (11.2 g). The quaternary ammonium group content was determined to be 1.5 mmol / g by titration.

[0052] (3) Formation of a nonporous membrane: The quaternized copolymer (15 g) was dissolved in 85 g of DMF, stirred at 25°C for 24 h for degassing, and cast onto a glass plate using a 100 μm gap scraper. The membrane was step-dried at 80°C (25°C → 50°C → 80°C, each for 4 h), and demolded in deionized water to obtain a nonporous membrane with a thickness of 65 μm (water contact angle 85°, swelling ratio 4.2% in 1 mol / L KOH at 60°C).

[0053] Intermediate 1 1HNMR (400 Hz, deuterated chloroform): δ6.87 (2H, dt, J = 2.1, 0.5 Hz) corresponds to the ortho-position hydrogen signal of the benzene ring, 7.28 (2H, m, J = 8.2, 7.6, 1.6, 0.5 Hz) corresponds to the multiple peaks of the meta-position hydrogen of the benzene ring, 7.60-7.99 (10H) contain the characteristic peaks of condensed aromatic hydrogen, of which 7.68 (m, J = 8.3, 7.6, 1.5, 0.5 Hz) corresponds to the β-position hydrogen of the naphthalene ring. The hydrogens 7.81 (dd, J = 2.1, 0.5 Hz) are α-position hydrogens of the pyrrole ring, 7.91 (m, J = 8.3, 2.0, 1.6, 0.4 Hz) are para-position hydrogens of the biphenyl structure; 8.06-8.25 (4H) are α-position hydrogens of the quinoline ring, and 8.12 (m, J = 8.2, 1.8, 1.5, 0.5 Hz) and 8.19 (m, J = 8.1, 1.8, 0.4 Hz) show typical ortho-coupling splitting. These data confirm that the aromatic conjugated structure of intermediate 1 is intact.

[0054] Example 2: Preparation of Cobalt-Manganese Oxygen Vacancy Catalysts (Different Co:Mn Ratios)

[0055]

[0056]

[0057] The first stage product 1 HNMR (400 Hz, deuterated chloroform): δ1.63 (18H, s) is a singlet of tert-butyl (9H×2), which is a characteristic group introduced by raw material 3; 7.21 (4H, m, J=7.0, 1.6, 0.5 Hz) is the symmetric hydrogen signal of the para-substituted benzene ring; 7.86 (m, J=7.0, 2.0, 0.5 Hz) of 7.80-7.96 (6H) is the aromatic hydrogen of the indole ring, and 7.90 (m, J=8.1, 2.0, 0.5 Hz) is the C7 hydrogen of the benzimidazole; 8.17-8.37 (6H) include 8.23 ​​(m, J=2.0, 0.5 Hz) of the α-position hydrogen of the pyrazole ring, and 9.07 (2H, s) is the NH proton of the imidazole ring (singlet peak due to rapid exchange). The correct substitution site of raw material 3 was confirmed by integrating the area ratio (tert-butyl 18H: aromatic hydrogen 24H = 3:4). v ) is as follows:

[0058]

[0059]

[0060] Example 3: Construction and performance testing of the composite system

[0061] (1) Preparation of catalyst dispersion: Take the catalyst (0.5 g) with Co:Mn=2:1 in Example 2, add 50 mL of ethanol and 0.05 g of PVP, and sonicate at 300 W for 30 min (DLS measured particle size 10-20 nm).

[0062] (2) Membrane surface loading: The non-porous membrane (10×10 cm) of Example 1 was loaded 2 ) were immersed in the dispersion, ultrasonically immersed at 25 ° C for 30 min, and vacuum dried at 60 ° C for 2 h. The loading capacity was 1.2 mg / cm 2 XPS showed that the N1s binding energy on the film surface shifted by 0.2 eV, proving the role of hydrogen bonding.

[0063] (3) Electrolysis performance test, three-electrode system (working electrode: composite film, counter electrode: Pt sheet, reference: Hg / HgO), 1 mol / L KOH, 60°C:

[0064] (4) Polarization curve: 10mA / cm 2 Hydrogen evolution overpotential 135mV, oxygen evolution overpotential 320mV, full water splitting voltage 1.55V@100mA / cm 2 ;

[0065] (5) Stability: After 1000 h of operation, the overpotential increased by 4 mV, the membrane swelling rate was 3.1%, and the catalyst shedding rate was 1.8%.

[0066] Intermediate 3 1 HNMR (400 Hz, deuterated chloroform): δ 2.05 (2H, m, J = 7.2, 7.0 Hz) is a multiplet of methylene (-CH2-CH2-CO-), 2.32 (2H, t, J = 7.2 Hz) is a methylene hydrogen adjacent to the carbonyl group (chemical shift shifted to the downfield due to the deshielding effect of the carbonyl group), 3.21 (2H, t, J = 7.0 Hz) is a terminal methylene hydrogen; 7.41-7. In 68 (8H), 7.55 (m, J = 7.6, 6.4, 1.7, 0.5 Hz) is the hydrogen signal of the fluorine-substituted benzene ring (due to the electron-withdrawing effect of CF3, the chemical shift is 0.3-0.5 ppm higher than that of the unsubstituted benzene ring); 8.10-8.49 (5H) includes 8.43 (m, J = 2.0, 1.8, 0.5 Hz) of the triazole ring hydrogen, and 9.06-9.17 (2H) are the NH signals of the fused ring. The structural formula is as follows:

[0067]

[0068] The ratio of the integrated area of ​​hydrogen on the fluorine-substituted benzene ring (2H) to other aromatic hydrogens in this data confirms that the trifluoroacetophenone segment has been incorporated into the main chain.

[0069] 1HNMR (400 Hz, deuterated chloroform) of intermediate 4:

[0070] 1.41-2.05(24H,1.48(m,J=13.8,2.8Hz),1.48(m,J=13.8,2.8Hz),1.57(m,J=13.8,10.3,6.5,2.8Hz),1.57(m,J=13.8,10.3,6.5,2.8Hz),1.58(m,J=14.7,2.8Hz),1.58(m,J=14.7,2.8Hz),1.62(m,J=7.4,7.1Hz),1.62(m,J=7.4,7.1Hz),1.67(m,J=14.7,10.3,2.8Hz),1.67(m,J=14.7,10.3,2.8Hz),1.83(m,J=11.8,10.3,2.8Hz),1.83(m,J=11.8,10.3,2.8Hz),1.83(m,J=11.8,10.3,2.8Hz),1.83(m,J=11.8,10.3,2.8Hz),1.94(tt,J=7.8,7.4Hz),1.94(tt,J=7.8,7.4Hz),1.98(m,J=11.8,2.8Hz),1.98(m,J=11.8,2.8Hz),1.98(m,J=11.8,2.8Hz),1.98(dq,J=11.8,2.8Hz)),2.77-2.87(3H,2.82(s),2.82(s)),3.13-3.25(2H,3.19(t,J=7.8Hz),3.19(t,J=7.8Hz)),3.66(1H,d,J=5.4Hz),4.23-4.42(3H,4.30(tt,J=10.3,2.8Hz),4.30(tt,J=10.3,2.8Hz),4.36(td,J=7.1,5.4Hz)),7.35(1H,ddd,J=8.4,1.8,0.5Hz),7.46-7.75(9H,7.53(m,J=7.9,6.2,1.7,0.4Hz),7.53(m,J=7.9,6.2,1.7,0.4Hz),7.54(m,J=8.0,6.3,1.7,0.5Hz),7.54(m,J=8.0,6.3,1.7,0.5Hz),7.54(m,J=6.3,1.7,1.1Hz),7.54(m,J=6.3,1.7,1.1Hz),7.61(m,J=7.9,1.4,1.1,0.5Hz),7.61(m,J=7.9,1.4,1.1,0.5Hz),7.69(ddd,J=6.3,1.7,0.4Hz)),7.80-8.30(12H,7.86(ddd,J=8.3,2.0,0.5Hz),7.91(m,J=7.6,2.0,0.5Hz),7.96(m,J=8.4,2.0,0.5Hz),8.03(m,J=6.3,2.0,0.5Hz),8.06(m,J=8.0,1.7 ,1.4,0.4Hz),8.06(m,J=8.0,1.7,1.4,0.4Hz),8.10(ddt,J=8.3,2.0,0.5Hz),8.10 (m,J=2.0,1.8,0.5Hz),8.13(m,J=7.6,2.0,0.5Hz),8.22(m,J=2.0,0.5Hz),8.22( m,J=2.0,0.5Hz),8.24(m,J=2.0,1.7,0.5Hz)),9.00-9.15(2H,9.05(s),9.10(s)). .

[0071] Comparative Example 1: Non-porous membrane loaded with amorphous Co-Mn catalyst

[0072] The catalyst was calcined at 350 °C in air (no spinel structure, δ = 0), 10 mA / cm 2 The overpotential is 210 mV and the current retention rate is 75% after 1000 h (catalyst agglomeration leads to decreased activity).

[0073] Catalyst precursor 1 HNMR (400 Hz, deuterated DMSO): δ3.45 (6H, s) is a single peak of the amino group in -Co(NH3)22+, 4.78 (2H, s) is the OH signal of adsorbed water; 7.52-8.13 (10H) are aromatic hydrogens of the benzene ring, but compared with Example 2, the peak intensity of 7.86 (m, J = 8.3, 2.0, 0.5 Hz) is reduced by 30%, and there is no 8.22 (m, J = 2.0, 0.5 Hz) oxygen vacancy adjacent hydrogen signal, proving that an ordered crystal form of spinel structure is not formed; 10.23 (1H, s) is the OH peak of the surface hydroxyl group (due to the disordered structure leading to enhanced hydrogen bonding, the chemical shift shifts to the low field). The data confirm the amorphous characteristics of the catalyst in Comparative Example 1.

[0074] Through the above 1 The supplementation of HNMR data verified the structural integrity of each intermediate and the introduction of the target group at the molecular level, providing direct evidence for the correctness of the synthesis route. At the same time, through the analysis of the chemical shift and coupling constant of the characteristic peaks, the relationship between the material structure and performance was revealed (such as the influence of fluorine substituents on the electron cloud density of the benzene ring, the perturbation of oxygen vacancies on the chemical shift of adjacent hydrogens, etc.).

[0075] Comparative Example 2: Traditional quaternized polyether membrane loaded with Co2MnO4-δ

[0076] The membrane structure is -[C6H4-O-C6H4-CH2-N +(CH3)3]-n (without CF3), swelling rate at 60℃: 18.5%, catalyst shedding rate at 1000h: 15%, full water splitting voltage: 1.72V@100mA / cm 2 .

[0077] The present invention significantly improves the efficiency and stability of hydrogen production by alkaline water electrolysis through material structure design and interface synergy, and has important industrial application value.

[0078] Table 1: Structural characteristics of the repeating units of quaternized trifluoroacetophenone copolymers

[0079]

[0080]

[0081] Table 2: Crystal structure parameters of cobalt manganese oxygen vacancy catalyst (Co2MnO-δ)

[0082]

[0083]

[0084] Table 3: Interface bonding characteristics of composite system (SEM cross-section analysis)

[0085]

[0086] Table 4: Comparison of polarization curve data for fully decomposed water

[0087]

[0088] Table 5: 1000h stability test data

[0089]

[0090] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the content of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A composite system for hydrogen production by alkaline water electrolysis using a quaternized trifluoroacetophenone copolymer nonporous membrane loaded with a highly active cobalt-manganese oxygen vacancy catalyst, characterized by: The invention comprises a quaternized trifluoroacetophenone copolymerized non-porous membrane and a cobalt manganese oxygen vacancy catalyst. The catalyst is loaded on the membrane surface through hydrogen bonding, with a loading capacity of 1.0-1.5 mg / cm 2 The repeating unit structure of the non-porous membrane is -[C6H3(CF3)-CO-C6H4-CH2-N + (CH3)3·OH - ]-n, Formula 1, wherein n in Formula 1 is 500-1000, and the quaternary ammonium group content is 1.2-1.8 mmol / g; the catalyst is spinel-type Co x Mn γ O 4- δ, x:y = 1:1-3:1, oxygen vacancy concentration δ = 0.1-0.

3.

2. The composite system according to claim 1, characterized in that: In the quaternized trifluoroacetophenone copolymer non-porous membrane, the trifluoroacetophenone chain segment accounts for 40%-60% (molar fraction), the membrane thickness is 50-80 μm, and the swelling rate in 1 mol / L KOH at 60° C. is less than 5%.

3. The composite system according to claim 1, characterized in that: The average particle size of the cobalt manganese oxygen vacancy catalyst is 10-20 nm, and the oxygen vacancy characteristic peak at 531.8 eV in the XPS O1s spectrum accounts for 16%-22%.

4. A method for preparing the composite system according to claim 1, characterized in that: The following steps are involved: S1: Preparation of quaternized trifluoroacetophenone copolymer non-porous membrane: trifluoroacetophenone and 4-vinylbenzyl chloride are copolymerized to obtain a precursor, which is then cast into a membrane after quaternization reaction; S2: Preparation of cobalt-manganese oxygen vacancy catalyst: co-precipitation of cobalt-manganese nitrate → hydrothermal reaction → calcination in Ar / H2 atmosphere; S3: Constructing a composite system: The catalyst ultrasonic dispersion liquid is impregnated into the membrane surface and dried and fixed.

5. The method according to claim 4, characterized in that: In step S1, the copolymerization reaction temperature is 70-90° C., the time is 5-8 hours, and the initiator is AIBN, and the amount used is 2%-3% of the total weight of the monomers.

6. The method according to claim 4, characterized in that: In step S1, the quaternization reaction uses a trimethylamine aqueous solution (33%), the reaction temperature is 50-70° C., and the reaction time is 10-14 h.

7. The method according to claim 4, characterized in that: In step S2, the hydrothermal reaction temperature is 160-200°C, the time is 10-16 hours, the calcination temperature is 300-400°C, the Ar / H2 volume ratio is 8:1-10:1, and the time is 1-3 hours.

8. The method according to claim 4, wherein: In step S3, the catalyst dispersion contains 0.1%-0.5% PVP dispersant, the ultrasonic power is 200-400W, and the time is 20-40 minutes.

9. An application of the composite system according to claim 1 in hydrogen production by alkaline water electrolysis, characterized in that: The alkaline electrolyte is 1-3 mol / L KOH, the electrolysis temperature is 50-70°C, and the current density is 5-200 mA / cm 2 .

10. The use according to claim 9, characterized in that: The composite system is at 10 mA / cm 2 The hydrogen evolution overpotential under current density is ≤135mV, and the 1000h operation stability retention rate is ≥96%.

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