Imidazolium group prompted alkaline anion-exchange membrane with high performance for efficient electrochemical CO_(2) conversion

Development of high-performance hydroxide-conductive membranes is a focus research subject owing to promising applications in electrochemical reduction of CO_(2)(eCO_(2)RR).However,few satisfactory membranes have been developed to maximize the performance of CO_(2) electrolyzers,despite its role as the core in regulating ion transport and preventing product crossover or fuel loss.Herein,we report the synthesis of alkaline anion-exchange membranes fabricated by poly(vinyl-alcohol)(PVA)and poly[(3-methyl-1-vinylimidazoliummethylsulfate)-co-(1-vinylpyrrolidone)](PQ44)for use in CO_(2) electrolysis.Owing to the unique imidazolium ring structure coupled with a three-dimensional semiinterpenetrating porous internal architecture,the PVA/PQ44-OH-membranes provide a high hydroxide conductivity(21.47 mS cm^(-1)),preferable mechanical property and thermal stability.In particular,the eCO_(2)RR used PVA/PQ44-OH^(-) as electrolyte membrane realized a charming Faradaic efficiency(88%)and partial current density(29 mA cm^(-2))at0.96 VRHE and,delivered the excellent durability over 20 h electrolysis in 0.5 mol L^(-1) KHCO_(3) electrolyte.Notably,it can even enable an ultrahigh current density beyond 100 mA cm^(-2) at^(-1).11 VRHE when the electrolyte was KOH instead,and produced the FEHCOOof 85%at a low potential of0.81 VRHE,superior to both commercial alkaline A201 and acidic Nafion117 membrane.

Two dimensional MoS_(2) finding its way towards constructing high-performance alkaline recovery membranes

The available alkaline recovery membranes are currently dominated by polymeric materials,but they suffer from a permeation-selectivity trade-off and inferior chemical resistance.Robust two dimensional(2D) lamellar membranes with sub-nanometer wide channels are promising candidates for discerning OH^(-)and other anions.Here,we report the development of alkaline recycling membranes through stacking MoS_(2) nanosheets.Benefiting from the ordered and narrow 2D channels,MoS_(2) membranes show excellent alkaline recovery performances.The OH^(-)dialysis coefficient (U_(OH)-) and separation factor (S)towards simulated OH^(-) and WO_(4)^(2-) across the 500 nm thick MoS_(2) laminates reach 6.9×10^(-3)m·h^(-1)and 34.3 respectively.Furthermore,the chemical environments of MoS_(2) laminates were modulated by intercalating ionic poly(sodium 4-styrene sulfonate)(PSS@MoS_(2)).The U_(OH)-and S values of PSS@MoS_(2) membrane further improve to 11.7×10^(-3)m·h^(-1)and 49.8 respectively.Besides,both MoS_(2) and PSS@MoS_(2) membranes exhibit promising stability.

Durable poly(binaphthyl-co-p-terphenyl piperidinium)-based anion exchange membranes with dual side chains

Building well-developed ion-conductive highways is highly desirable for anion exchange membranes(AEMs).Grafting side chain is a highly effective approach for constructing a well-defined phaseseparated morphological structure and forming unblocked ion pathways in AEMs for fast ion transport.Fluorination of side chains can further enhance phase separation due to the superhydrophobic nature of fluorine groups.However,their electronic effect on the alkaline stability of side chains and membranes is rarely reported.Here,fluorine-containing and fluorine-free side chains are introduced into the polyaromatic backbone in proper configuration to investigate the impact of the fluorine terminal group on the stability of the side chains and membrane properties.The poly(binaphthyl-co-p-terphenyl piperidinium)AEM(QBNp TP)has the highest molecular weight and most dimensional stability due to its favorable backbone arrangement among ortho-and meta-terphenyl based AEMs.Importantly,by introducing both a fluorinated piperidinium side chain and a hexane chain into the p-terphenyl-based backbone,the prepared AEM(QBNp TP-QFC)presents an enhanced conductivity(150.6 m S cm^(-1))and a constrained swelling at 80℃.The electronic effect of fluorinated side chains is contemplated by experiments and simulations.The results demonstrate that the presence of strong electro-withdrawing fluorine groups weakens the electronic cloud of adjacent C atoms,increasing OH^(-)attack on the C atom and improving the stability of piperidinium cations.Hence QBNp TP-QFC possesses a robust alkaline stability at 80℃(95.3%conductivity retention after testing in 2 M Na OH for 2160 h).An excellent peak power density of 1.44 W cm^(-2)and a remarkable durability at 80℃(4.5%voltage loss after 100 h)can be observed.

Synthesis and characterization of quaternized poly(phthalazinone ether sulfone ketone)for anion-exchange membrane

Chloromethylated poly（phthalazinone ether sulfone ketone） （CMPPESK） was prepared from poly（phthalazinone ether sulfone ketone） （PPESK） using chloromethyl octyl ethers （CMOE） with lower toxicity as chloromethylated regent. CMPPESK was soluble in N-methyl-2-pyrrolidone （NMP）, N,N-dimethylacetamide （DMAc） and chloroform. Quaternized poly（phthalazinone ether sulfone ketone） （QAPPESK） was prepared from CMPPESK by quaternization. QAPPESK had excellent solvent resistance, which was only partly soluble in sulfuric acid （98%） and swollen in N,N-dimethylformamide （DMF）. The vanadium redox flow battery （V-RFB） using QAPPESK anion-exchange membrane had better performance with 88.3% of overall energy efficiency.

Phosphate removal from aqueous solution by Donnan dialysis with anion-exchange membrane

The removal of phosphate from aqueous solution by Donnan dialysis with anion-exchange membrane was investigated.The results show that phosphate could be removed from aqueous solution without supplying external high pressure or electrical potential.Under the conditions of influent phosphate of 2.0 mg/L,counterion(Cl-)concentration of 0.1 mol/L,stirring speed of 500 r/min and phase temperature of 298 K,the removal of phosphate achieves 70.0%.Decreasing counterion concentration has little influence on the removal of phosphate,but phosphate amount in anion-exchange membrane increases significantly.With the increase of stirring speed and phase temperature,the removal efficiency of phosphate greatly is improved.Existing forms of phosphate in aqueous solution affected transport of phosphate and only strong acidic pH of feed solution(pH=3.0)decreases the removal of phosphate.Transport of phosphate is also accompanied by change of pH value of feed solution.In consequence,it might be a promise potential process for phosphate advanced wastewater treatment,especially in the area where high salted nature water can be utilized.

Ternary layered double hydroxide oxygen evolution reaction electrocatalyst for anion exchange membrane alkaline seawater electrolysis

Anion exchange membrane(AEM)water electrolyzers are promising energy devices for the production of clean hydrogen from seawater.However,the lack of active and robust electrocatalysts for the oxygen evolution reaction(OER)severely impedes the development of this technology.In this study,a ternary layered double hydroxide(LDH)OER electrocatalyst(NiFeCo-LDH)is developed for high-performance AEM alkaline seawater electrolyzers.The AEM alkaline seawater electrolyzer catalyzed by the NiFeCo LDH shows high seawater electrolysis performance(0.84 A/cm^(2)at 1.7 Vcell)and high hydrogen production efficiency(77.6%at 0.5 A/cm^(2)),thus outperforming an electrolyzer catalyzed by a benchmark IrO_(2)electrocatalyst.The NiFeCo-LDH electrocatalyst greatly improves the kinetics of the AEM alkaline seawater electrolyzer,consequently reducing its activation loss and leading to high performance.Based on the results,this NiFeCo-LDH-catalyzed AEM alkaline seawater electrolyzer can likely surpass the energy conversion targets of the US Department of Energy.

Electrodeposition conditions of metallic nickel in electrolytic membrane reactor

The process parameters were optimized for the eleetrodeposition of nickel in an electrolytic membrane reactor. Nickel（Ⅱ） and boric acid concentrations, pH and temperature were varied to evaluate the changes in current efficiency and specific energy consumption of nickel electrodeposition. The catholyte was aqueous nickel（Ⅱ） sulfate and boric acid, and the anolyte was sulfuric acid solution. An anionic membrane separated the anolyte from the catholyte while maintained a conductive path between the two compartments. The results indicated that the cathode current efficiency increased with the increase of nickel concentration, pH and boric acid concentration, and decreased with the increase of current density and stirring rate. A maximum current efficiency of 97.15% was obtained under the optimized conditions of electrolyte composition of 40 g/L Ni and 40 g/L boric acid at temperature of 42 ℃ and pH of 6 with a cathode current density of 300 A/m2.

Supramolecular Polymer Intertwined Free-Standing Bifunctional Membrane Catalysts for All-Temperature Flexible Zn-Air Batteries

Rational construction of flexible free-standing electrocatalysts featuring long-lasting durability,high efficiency,and wide temperature tolerance under harsh practical operations are fundamentally significant for commercial zinc-air batteries.Here,3D flexible free-standing bifunctional membrane electrocatalysts composed of covalently cross-linked supramolecular polymer networks with nitrogen-deficient carbon nitride nanotubes are fabricated(referred to as PEMAC@NDCN)by a facile self-templated approach.PEMAC@NDCN demonstrates the lowest reversible oxygen bifunctional activity of 0.61 V with exceptional long-lasting durability,which outperforms those of commercial Pt/C and RuO_(2).Theoretical calculations and control experi-ments reveal the boosted electron transfer,electrolyte mass/ion transports,and abundant active surface site preferences.Moreover,the constructed alkaline Zn-air battery with PEMAC@NDCN air-cathode reveals superb power density,capacity,and discharge-charge cycling stability(over 2160 cycles)compared to the reference Pt/C+RuO_(2).Solid-state Zn-air batteries enable a high power density of 211 mW cm^(−2),energy density of 1056 Wh kg^(−1),stable charge-discharge cycling of 2580 cycles for 50 mA cm^(−2),and wide temperature tolerance from−40 to 70℃with retention of 86%capacity compared to room-temperature counterparts,illustrating prospects over harsh operations.

Towards reliable assessment of hydrogen oxidation electrocatalysts for anion-exchange membrane fuel cells

Recent advancement of proton exchange membrane fuel cells has led to commercial sales of fuel-cell cars but market barrier exists because this technology heavily relies on platinum catalyst.Given the permission of adopting platinum-group-metal-free catalysts,anion-exchange membrane fuel cell has received notable attention.However,the sluggish kinetics of anodic hydrogen oxidation reaction(HOR)largely limit the cell efficiency.Although many high-performance HOR catalysts have been reported,there are analytical uncertainties in the literature concerning the assessment of the catalyst activity.Here we determine the origin of false HOR currents in the recorded polarization curves and propose a rigorous approach to eliminate them.We unveil experimentally the uncertainties of obtaining exchange current densities(j0)using Tafel plot from Bulter–Volmer equation and recommend employing the micro-polarization region method.For bulky catalysts that cannot establish a well-defined diffusion layer,we suggest applying external stirring bar to offer certain level of enforced convection and using j0 to compare the activity.

超支化芘基聚芳基哌啶阴离子交换膜及其碱性电解水应用

以芘(py)为支化基团,基于对三联苯(TP)和N-甲基-4-哌啶酮(NM4P)单体,经强酸催化聚合得到超支化芘基聚三联苯哌啶聚合物(h-PTPE-py-n)。通过调整支化基团和三联苯的比例,可以得到不同支化度的超支化聚三联苯哌啶阴离子交换膜h-PTP-py-n。对该聚合物的化学结构、热性能、力学性能、离子传导性质进行了系统表征和测试,并将该类型膜应用于阴离子交换膜电解水(AEMWE)器件,评估其在实际工况下的运行基本表现。结果表明,芘引入导致的支化有效提高了阴离子交换膜的力学性能和尺寸稳定性,所制得的阴离子交换膜在80℃下的氢氧根离子传导率最高达到168.0 mS/cm,应用到AEMWE中时,h-PTP-py-n展示出了优异的导电性,在3 V条件下电流密度达到1.95 A/cm^(2),并且能稳定运行超过90 h。

固定化蛋壳膜碱性蛋白酶的制备及其酶学性质研究

采用交联法制备蛋壳膜碱性蛋白酶(ESM-BAP)。以酶活回收率、酶负载量和酶活负载量为指标,通过单因素试验优化交联工艺,利用扫描电镜和红外光谱对ESM-BAP进行表征,并对游离碱性蛋白酶(BAP)和ESM-BAP进行酶学性质分析。结果表明:最优交联工艺为京尼平质量浓度7.5 mg/mL、酶质量浓度5 mg/mL、交联时间2 h、交联温度45℃。扫描电子显微镜和红外光谱表征得出ESM-BAP制备成功;与游离碱性蛋白酶相比,ESM-BAP对温度、pH的耐受性能和酶活性能都有所提高。

菜籽饼超微粉酶解制备抗氧化活性肽

为探究菜籽饼超微粉直接酶解制备抗氧化肽技术,该研究以菜籽饼超微粉为原料,利用碱性蛋白酶、风味蛋白酶对其进行酶解,通过测定2,2’-联氮双(3-乙基苯并噻唑啉-6-磺酸)(ABTS)自由基清除能力、1,1-二苯基-2-苦基肼自由基清除能力和总抗氧化能力表征酶解产物体抗氧化活性,使用膜分离、Sephadex G-15凝胶层析对酶解产物进行分离纯化,利用高效液相色谱-串联质谱联用技术分析鉴定抗氧化活性组分的氨基酸序列。结果表明,风味蛋白酶酶解产物的肽含量较高,并以分子量小于1 kDa肽段为主,碱性蛋白酶解产物以5~10 kDa肽段为主,但同等浓度下(1 mg/mL)的碱性蛋白酶酶解产物抗氧化活性较高;膜分离后,同种酶解产物中低分子量(<1 kDa)组分具有更好的ABTS自由基清除能力和总抗氧化活性;通过凝胶层析分离纯化得到的高抗氧化活性组分J3经氨基酸序列鉴定,结合PeptideRanker生物活性预测筛选得到5个肽段,肽段的N-端均为苯丙氨酸且肽段中疏水性氨基酸的含量占比达50%以上。该结果可为深入开发菜籽饼蛋白资源提供理论参考。

可再生能源制氢技术及其主要设备发展现状及展望

【目的】分析我国“2030碳达峰、2060碳中和”双碳目标下的氢开发、推广和利用的必要性以及当前阶段我国的氢能开发政策和战略布局。【方法】通过调研绿氢制氢技术研究进展和成果,概述了电解水制氢技术及其主要装置,综述了电解水制氢装置的发展现状和发展趋势,重点分析了电解槽及其重要组成部件(如膜电极组件、氢能拉紧螺栓组件以及端压板等)的研究现状以及关键设备当前存在的主要问题。对碱性电解槽和PEM电解槽等制氢装置的未来发展趋势进行了展望。【结论】为制氢设备的未来发展提供了参考。

孔结构对碱性电解水制氢复合隔膜的应用影响

通过浸没沉淀相转化法制备了两种结构形式的碱性电解水制氢有机/无机复合隔膜,即断面海绵状孔结构和指状孔结构。研究了两种孔结构对碱性电解水制氢隔膜的应用影响,通过评价两种孔结构隔膜的综合性能,包括阻气性、面电阻、机械性能和耐腐蚀性。结果表明:此两种结构形式的隔膜泡点(约0.335MPa)和抗拉强度(约28.52N/mm^(2))接近,但海绵状孔结构的隔膜具有更低的面电阻0.21Ω/cm^(2)和更优异的机械性能,经过耐磨和耐压后泡点降低幅度小,阻气性更高,而断面指状孔结构的隔膜面电阻0.25Ω/cm^(2),经过耐磨和耐压后泡点降低幅度较大,可以推断出两种结构形式的隔膜阻气方式有所不同,海绵状孔结构隔膜整体结构具有阻气效果,而指状孔结构隔膜主要靠致密皮层阻气,皮层损坏则失去阻气效果。另外,两种结构的复合隔膜耐碱腐蚀性相差较大,断面指状孔结构的隔膜经过长期高温碱液浸表面致密层消失,无阻气性。通过对比两种不同结构隔膜的性能,海绵状孔结构的隔膜综合性能更加优异,更适合碱性电解水制氢设备。

基于混合电解槽制氢系统的功率分配技术

光伏(PV)电解水制氢技术是实现PV消纳和绿电制氢的重要手段。在波动电源输入状态下,电解槽制氢系统运行稳定性及制氢经济性存在较多问题。针对这些问题,提出基于混合电解槽制氢系统的PV制氢方案,采用碱性电解槽(AEL)制氢系统与质子交换膜电解槽(PEMEL)系统相结合的方法,提出混合电解槽制氢系统功率优化控制技术和容量配置方法,在实现不同类型电解槽组合运行、合理配置的基础上,提升制氢性能。结果表明,混合电解制氢系统与单一AEL制氢技术相比,制氢量提升了5%,波动率大幅降低,制氢成本相较于PEMEL电解水制氢系统大幅降低。采用功率优化控制技术后,同等功率运行下,制氢量提升。单一电解槽处于波动工况下,采用阵列轮换方式保证了电解槽系统安全运行。研究结果可以为实现PV消纳以及多类型电解槽安全运行模式提供参考。

混合电解槽制氢系统选型及评估方法

电解槽是光伏电解水制氢技术的关键设备,其性能的优劣是影响制氢技术发展的关键因素。目前已被投入工程应用的电解槽有碱性电解槽(alkaline electrolyzer,AEL)和质子交换膜电解槽(protonexchange membrane electrolyzer,PEMEL),两类电解槽在经济性和技术性方面各有优劣。因此,提出混合电解槽应用技术。首先,提出层次分析-熵权法综合评估方法,按照所提方法求得混合电解槽系统最优选型;其次,将混合电解槽系统应用在光储耦合制氢系统中,并搭建其仿真模型;在此基础之上,进行3类电解槽多个性能指标对比分析。结果表明,混合电解槽成本为同容量PEMEL设备成本的56%,且混合电解槽电解效率可达91.5%,验证了所提方案的适用性。

电解水制氢用阴离子交换膜研究进展

阴离子交换膜电解水制氢融合了碱性电解水和质子交换膜电解水制氢技术的优点,具有电解效率高、响应速度快、成本低等特点,被认为是目前最有前景的可再生绿色能源制氢技术之一。阴离子交换膜(AEM)是提供OH-离子传导和阻隔气体交叉的关键部件,其直接影响了阴离子交换膜电解水系统的性能和使用寿命。然而,目前的AEM隔膜面临着离子电导率低和稳定性差的问题。本文首先介绍了AEM在电解槽中的作用,高性能AEM应满足的性能要求和评价参数,并重点讨论了OH-在AEM中的传输机制与影响因素。接着,本文进一步概述了AEM的结构组成,以及常见的阳离子基团和聚合物主链类型;阐述了不同阳离子基团的降解机理和聚合物主链的特点,重点阐释了阳离子官能团稳定性设计的策略,聚合物主链改性制备的方法,以及AEM性能表现。最后,展望了AEM隔膜未来面临的挑战和潜在研究方向,指出应在设计耐碱稳定性AEM的基础上,通过交联、嵌段共聚、侧链接枝和复合膜技术等策略构建和制备满足实际应用需求的高性能AEM隔膜,为AEM进一步发展提供借鉴和参考。

反渗透膜污染类型分析及清洗方案优化研究

某反渗透膜系统运行中出现污堵现象,表征分析可知该膜系统为有机/无机复合污染,且以有机污染为主。平板膜实验结果表明污堵膜元件脱盐率仅为42%,经装置现行碱洗方案清洗后脱盐率为63%,膜性能恢复程度有限。清洗方案优化研究发现,碱洗方案为NaOH+0.05%十二烷基硫酸钠+0.5%EDTA-4Na与NaOH+0.04%十二烷基苯磺酸钠+0.5%EDTA-4Na时,清洗后膜片脱盐率可分别恢复至77%,71%,清洗效果均优于装置目前现行碱洗方案,有利于膜系统高效稳定运行。

电解制氢产业的基础研究

文章从政策、技术、市场三个方面对电解制氢产业进行介绍,同时对我国氢能产业支持政策进行了介绍,通过对比现有的电解制氢工艺,对技术特性、优缺点及应用现状进行了总结,最后整理了国内外绿氢项目的发展现状,旨为同行了解电解制氢产业提供参考。

PEM电解制氢与ALK电解制氢的比较综述

通过综合回顾和分析现有文献,对纯水质子交换膜(PEM)电解制氢和碱性(ALK)电解制氢两种主要电解制氢技术进行了比较研究。首先介绍了这两种电解制氢技术的原理和应用,然后重点对其在电解槽结构、电解质、电极材料、反应机理、效率和环境友好性等方面的差异进行了详细分析。最后,对两种技术的优缺点和未来发展方向进行了讨论。