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Recent progress of Pt-based oxygen reduction reaction catalysts for proton exchange membrane fuel cells

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Rare Metals 2024年第6期43卷 2444-2468页

作者： Feng Zhan Kun-Song Hu Jin-Hua Mai Li-Sheng Zhang Zhen-Guo Zhang huan he Xin-Hua Liu School of Resources Environment and MaterialsGuangxi UniversityNanning530004China School of Transportation Science and Engineering Beihang UniversityBeijing 102206China IDTECH(Suzhou)Co.Ltd Suzhou 215217China Dyson School of Design Engineering Imperial College LondonLondon SW72AZUK

With the increasing consumption of fossil fuels,proton exchange membrane fuel cells(PEMFCs)have attracted considerable attention as green and sustainable energy conversion *** slow kinetics of the cathodic oxygen reduction reaction(ORR)has a major impact on the performance of PEMFCs,and although platinum(Pt)can accelerate the reaction rate of the ORR,the scarcity and high cost of Pt resources still limit the development of ***,the development of low-cost high-performance ORR catalysts is essential for the commercial application and development of *** paper reviews the research progress of researchers on Pt-based ORR catalysts in recent years,including Pt/C catalysts,Pt-based alloy catalysts,Pt-based intermetallic compounds,and Pt-based single-atom catalysts(SACs),with a focus on Pt-based alloy catalysts with different *** described in detail the difficulties and solutions in the research process of various ORR catalysts and explained the principle of their activity enhancement with density functional theory(DFT).In addition,an outlook on the development of Pt-based catalysts is given,and reducing the amount of Pt used and improving the performance of catalysts are the directions to work on in the coming period.

关键词： Pt-based catalysts PEMFCs Pt-based intermetallic compounds Single-atom catalysts

Double-confined nanoheterostructure Sb/Sb_(2)S_(3)@Ti_(3)C_(2)T_(x)@C toward ultra-stable Li-/Na-ion batteries

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Rare Metals 2024年第5期43卷 2067-2079页

作者： Dan Wang Qun Ma huan he Zhi-Yuan Wang Run-Guo Zheng Hong-Yu Sun Yan-Guo Liu Chun-Li Liu School of Materials Science and Engineering Northeastern UniversityShenyang110819China School of Resources and Materials Northeastern University at QinhuangdaoQinhuangdao 066004China Key Laboratory of Dielectric and Electrolyte Functional Material hebei Province Qinhuangdao 066004China Department of Physics and Oxide Research Center Hankuk University of Foreign StudiesYongin 17035Korea

Antimony-based materials with high capacities and moderate potentials are promising anodes for lithium-/-sodium-ion ***,their tremendous volume expansion and inferior conductivity lead to poor structural stability and sluggish reaction ***,a doubleconfined nanoheterostructure Sb/Sb_(2)S_(3)@Ti_(3)C_(2)T_(x)@C has been fabricated through a solvothermal method followed by low-temperature heat *** dual protection of“MXene”and“carbon”can better accommodate the volume expansion of Sb/Sb_(2)S_(3).The strong covalent bond(Ti-S,Ti-O-Sb,C-O-Sb)can firmly integrate Sb-based material with Ti_(3)C_(2)T_(x)and carbon,which significantly improves the structure *** addition,the carbon layer can restrain the oxidation of MXenes,and the nano-Sb/Sb_(2)S_(3)can facilitate electron/ion transport and suppress the restacking of *** heterogeneous interface between Sb and Sb_(2)S_(3)can further promote interfacial charge *** MXene-Sb/Sb_(2)S_(3)@C-1 with the optimal Sb content shows high specific capacities,comparable rate properties and ultra-stable cycling performances(250 m Ah·g^(-1)after 2500 cycles at 1 A·g^(-1)for sodium-ion batteries).Ex situ X-ray diffractometer(XRD)test reveals the storage mechanism including the conversion and alloying process of MXene-Sb/Sb_(2)S_(3)@*** voltammetry(CV)test results demonstrate that the pseudocapacitance behavior is dominant in MXene-Sb/Sb_(2)S_(3)@C-1,especially at large *** design paves the way for exploring high-performance alloy-based/conversion-type anode for energy storage devices.

关键词： Sb/Sb_(2)S_(3) MXene Carbon Anode Lithium-ion batteries Sodium-ion batteries

Sulfur doped iron-nitrogen-hard carbon nanosheets as efficient and robust noble metal-free catalysts for oxygen reduction reaction in PEMFC

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Journal of Energy Chemistry 2024年第2期89卷 422-433,I0010页

作者： Bin Liu Jiawang Li Bowen Yan Qi Wei Xingyu Wen Huarui Xie huan he Pei Kang Shen Zhi Qun Tian Collaborative Innovation Center of Sustainable Energy Materials School of Physical Science and TechnologyGuangxi UniversityGuangxi Key Laboratory of Electrochemical Energy MaterialsState Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite StructuresNanning 530004GuangxiChina

Transition metal-nitrogen-carbon(M-N-C)as a promising substitute for the conventional noble metalbased catalyst still suffers from low activity and durability for oxygen reduction reaction(ORR)in proton exchange membrane fuel cells(PEMFCs).To tackle the issue,herein,a new type of sulfur-doped ironnitrogen-hard carbon(S-Fe-N-HC)nanosheets with high activity and durability in acid media were developed by using a newly synthesized precursor of amide-based polymer with Fe ions based on copolymerizing two monomers of 2,5-thiophene dicarboxylic acid(TDA)as S source and 1,8-diaminonaphthalene(DAN)as N source via an amination *** as-synthesized S-Fe-N-HC features highly dispersed atomic Fe Nxmoieties embedded into rich thiophene-S doped hard carbon nanosheets filled with highly twisted graphite-like microcrystals,which is distinguished from the majority of M-N-C with soft or graphitic carbon *** unique characteristics endow S-Fe-N-HC with high ORR activity and outstanding durability in 0.5 M H_(2)SO_(4).Its initial half-wave potential is 0.80 V and the corresponding loss is only 21 m V after 30,000 ***,its practical PEMFC performance is a maximum power output of 628.0 mW cm^(-2)and a slight power density loss is 83.0 m W cm^(-2)after 200-cycle practical ***,theoretical calculation shows that the activity of Fe Nxmoieties on ORR can be further enhanced by sulfur doping at meta-site near FeN_(4)*** results evidently demonstrate that the dual effect of hard carbon substrate and S doping derived from the precursor platform of amid-polymers can effectively enhance the activity and durability of Fe-N-C catalysts,providing a new guidance for developing advanced M-N-C catalysts for ORR.

关键词： Transition metal-nitrogen-carbon Oxygen reduction reaction Hard carbon Amide based polymer reaction Proton exchange membrane cells

Dissolved organic matter accelerates microbial degradation of 17 alpha-ethinylestradiol in the presence of iron mineral

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Journal of Environmental Sciences 2024年第5期139卷 364-376页

作者： huan he Min Shi Xiaoxia Yang Juhong Zhan Yanting Lin Ziwei Guo Zhicheng Liao Chaochao Lai Xiaomin Ren Bin huang Xuejun Pan Faculty of Environmental Science and Engineering Kunming University of Science and TechnologyKunming 650500China Yunnan Provincial Key Lab of Soil Carbon Sequestration and Pollution Control Kunming 650500China Research Institute for Environmental Innovation(Suzhou)Tsinghua Suzhou 215163China

Dissolved organic matter(DOM)and iron minerals widely existing in the natural aquatic environment can mediate the migration and transformation of organic ***,the mechanism of interaction between DOM and iron minerals in the microbial degradation of pollutants deserves further *** this study,the mechanism of 17 alphaethinylestradiol(EE2)biodegradation mediated by humic acid(HA)and three kinds of iron minerals(goethite,magnetite,and pyrite)was *** results found that HA and iron minerals significantly accelerated the biodegradation process of EE2,and the highest degradation efficiency of EE2(48%)was observed in the HA-mediated microbial system with pyrite under aerobic ***,it had been demonstrated that hydroxyl radicals(HO·)was the main active substance responsible for the microbial degradation of ***·is primarily generated through the reaction between hydrogen peroxide secreted by microorganisms and Fe(II),with aerobic conditions being more *** presence of iron minerals and HA could change the microbial communities in the EE2 biodegradation *** findings provide new information for exploring the migration and transformation of pollutants by microorganisms in iron-rich environments.

关键词： Dissolved organic matter Iron mineral 17 alpha-ethinylestradiol Biodegradation

Design of a Metasurface Antenna Based on Characteristic Mode Theory

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电讯技术 2024年第10期64卷 1561-1568页

作者： he huan Southwest China Institute of Electronic Technology Chengdu 610036China

A novel metasurface antenna consisting of 5×5 rectangular patch elements is *** with and without the central element are both analyzed by the Characteristic Mode Theory(CMT).The developed mutually orthogonal principal modes of the optimized periodic patch structure areexcited by a center-feed dipole.A differential feeding network is employed to realize impedance *** with profile height of 0.07λ_(0)(λ_(0)is the wavelength in free space at the lowest operatingfrequency)is fabricated and assembled to verify the simulation *** measured results show that thereflectance coefficient of proposed matesurface antenna is less than-10 dB in the whole operating bandrange from 4.2 GHz to 5.5 GHz,a relative bandwidth of 26.8%is achieved,and the maximummeasured realized gain is more than 9 dBi with a maximum radiation efficiency of 90%.The designprovides a guideline on the application of characteristic modes(CMs)to radiation problems.

关键词： metasurface antenna characteristic mode theory dipole antenna realized gain

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公司分配视角下的股东身份从属债权劣后受偿

法学研究 2024年第1期46卷 110-128页

作者：何欢上海财经大学法学院

股东身份从属债权系股权转化成立的特殊股东债权,包括由股权固有内容具象而生的债权和非典型股权融资协议下依附于股权的债权。因与股权具有内在同一性,该类债权应劣后于普通债权受偿。某些债权虽非股权的转化,因债权人实际地位类似于股... 详细信息

股东身份从属债权系股权转化成立的特殊股东债权,包括由股权固有内容具象而生的债权和非典型股权融资协议下依附于股权的债权。因与股权具有内在同一性,该类债权应劣后于普通债权受偿。某些债权虽非股权的转化,因债权人实际地位类似于股东,亦得比照适用而劣后。股东身份从属债权劣后受偿能阻却公司经营风险的事后再分配与股东权利顺位的自行提升,为股债关联现象引发的公司分配难题提供更自洽的注解。基于该规则,可重廓公司分配制度的内在体系。资本维持原则和偿债能力标准仅关乎以股东与公司间不当利益转移的规制间接维护债权优先顺位,作用分别限于防范股东自公司获得不应有的法定权益性分配,以及股东与公司间交易有失公允而损及公司偿债能力。股东身份从属债权劣后受偿规则在权益性分配之债依法或依约成立时,避免因“股转债”造成股东与公司债权人间的事后风险不当分配。

关键词：公司分配资本维持偿债能力劣后债权对赌协议

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破产惩戒主义与破产救济主义的立法抉择

法学 2024年第10期 114-131页

作者：何欢上海财经大学法学院

作为当前我国债务清理法的立法取向,破产惩戒主义不区分破产债务人及其有关人员实际上有无不当行为,仅因债务人事实破产或进入破产程序便施以惩戒。其本质是破产有罪、有责理念的现代残余,破产法的当然失权规则和执行法的无差别执行制... 详细信息

作为当前我国债务清理法的立法取向,破产惩戒主义不区分破产债务人及其有关人员实际上有无不当行为,仅因债务人事实破产或进入破产程序便施以惩戒。其本质是破产有罪、有责理念的现代残余,破产法的当然失权规则和执行法的无差别执行制裁均为其体现。破产惩戒主义违反了债务清理的比例原则,无从正向引导当事人行为,所造成的职责错配有巨大的体系破坏力。在破产惩戒主义之下,即便为破产债务人提供救济也欠缺稳定的法律预期。债务清理法应改采破产救济主义,即宽容对待破产、重视对破产债务人的救济的立法取向。破产本身绝不等于法律上的过错,破产债务人救济在现代社会具有优越地位,构成债权实现的更优方式,也具有积极的宏观社会效益。在破产救济主义之下,破产债务人及其有关人员的不当行为也能得到更有效的规制。

关键词：破产惩戒主义破产救济主义破产失权执行制裁债务人救济

富营养化湖泊藻华腐解产生的溶解性有机质动态变化及其环境效应

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环境科学 2024年第3期45卷 1539-1552页

作者：张瑾陈明滢郝智能钟寰何欢雷沛南京大学环境学院污染控制与资源化研究国家重点实验室南京210023 南京师范大学环境学院南京210023 中国科学院生态环境研究中心环境化学与生态毒理学国家重点实验室北京100085 中国科学院大学北京100049 中国科学院生态环境研究中心环境水质学国家重点实验室北京100085

富营养化和有害藻华是湖泊面临的主要环境问题,富营养化湖泊藻华在后期会发生衰亡和腐解并产生大量藻源溶解性有机质(DOM),影响水体DOM的质量和活性,并对关键元素的生物地球化学循环产生重要调控作用.为探究不同富营养化程度湖泊水体藻... 详细信息

富营养化和有害藻华是湖泊面临的主要环境问题,富营养化湖泊藻华在后期会发生衰亡和腐解并产生大量藻源溶解性有机质(DOM),影响水体DOM的质量和活性,并对关键元素的生物地球化学循环产生重要调控作用.为探究不同富营养化程度湖泊水体藻华腐解过程,对藻华腐解过程中水体DOM总量、生物有效性、相对分子质量和组分的动态变化进行分析,并探讨了藻华腐解引发的环境效应.结果表明,藻华腐解显著提高DOM浓度、生物有效性和各荧光组分强度.随着腐解的进行,DOM浓度逐渐降低,而相对分子质量逐渐增大.在分子水平上,超高分辨率质谱结果显示腐解过程中不饱和烃和脂肪族化合物优先被微生物利用,并生成木质素、缩合烃和高O/C值的单宁酸等惰性分子.藻华腐解过程中细菌群落主要优势种从变形菌门(46%)逐渐变为拟杆菌门(42%).此外,藻华腐解还导致水体CO_(2)和CH_(4)排放显著升高1.2~5倍,且排放量可以由DOM光学指标a254预测.该结果为全面揭示藻华腐解过程中DOM特征的动态变化,以及湖泊富营养化治理和环境效应预测提供理论依据和科学支撑.

关键词：溶解性有机质生物有效性相对分子质量藻华腐解温室气体

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局部非线性结构自由界面子结构模态综合法

航空学报 2024年第13期45卷 296-308页

作者：谭星陈卫婷王陶何欢南京航空航天大学航空航天结构力学及控制全国重点实验室南京210016 南京航空航天大学振动工程研究所南京210016 南京工业大学应急管理学院南京210024

为了提高局部非线性结构的动响应计算效率,提出了一种考虑一般黏性阻尼的自由界面子结构模态综合法。首先,将整体系统按照局部非线性的位置划分为各个线性子结构。然后,利用一种不需要考虑子结构是否有刚体模态的剩余模态集构造方式,构... 详细信息

为了提高局部非线性结构的动响应计算效率,提出了一种考虑一般黏性阻尼的自由界面子结构模态综合法。首先,将整体系统按照局部非线性的位置划分为各个线性子结构。然后,利用一种不需要考虑子结构是否有刚体模态的剩余模态集构造方式,构造出用于降阶的缩减模态集。在降阶过程中,通过忽略与高阶模态相关的阻尼力和惯性力,建立了非线性界面力和模态位移、模态速度之间的近似关系式。基于此关系式,将非线性界面力、模态位移和模态速度作为变量放入状态空间,并利用界面协调关系进行子结构降阶模型综合。最后,通过一个含立方非线性弹簧与阻尼连接的弹簧质量块系统和一个含非线性中介支承的双转子系统对所提方法的有效性进行了验证。

关键词：局部非线性一般黏性阻尼子结构模态综合自由界面双转子系统