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Review of characterization and modeling of polymer electrolyte fuel cell catalyst layer: The blessing

Jun HUANG, Zhe LI, Jianbo ZHANG

《能源前沿（英文）》 2017年 第11卷 第3期   页码 334-364 doi: 10.1007/s11708-017-0490-6

摘要： Ionomer impregnation represents a milestone in the evolution of polymer electrolyte fuel cell (PEFC) catalyst layers. Ionomer acts as the binder, facilitates proton transport, and thereby drastically improves catalyst utilization and effectiveness. However, advanced morphological and functional characterizations have revealed that up to 60% of Pt nanoparticles can be trapped in the micropores of carbon support particles. Ionomer clusters and oxygen molecules can hardly enter into micropores, leading to low Pt utilization and effectiveness. Moreover, the ionomer thin-films covering Pt nanoparticles can cause significant mass transport loss especially at high current densities. Ionomer-free ultra-thin catalyst layers (UTCLs) emerge as a promising alternative to reduce Pt loading by improving catalyst utilization and effectiveness, while theoretical issues such as the proton conduction mechanism remain puzzling and practical issues such as the rather narrow operation window remain unsettled. At present, the development of PEFC catalyst layer has come to a crossroads: staying ionomer-impregnated or going ionomer-free. It is always beneficial to look back into the past when coming to a crossroads. This paper addresses the characterization and modeling of both the conventional ionomer-impregnated catalyst layer and the emerging ionomer-free UTCLs, featuring advances in characterizing microscale distributions of Pt particles, ionomer, support particles and unraveling their interactions; advances in fundamental understandings of proton conduction and flooding behaviors in ionomer-free UTCLs; advances in modeling of conventional catalyst layers and especially UTCLs; and discussions on high-impact research topics in characterizing and modeling of catalyst layers.

关键词： polymer electrolyte fuel cell     ultra-thin catalyst layer     electrostatic interactions     characterization and modeling     structure-property-performance relation     water management    

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Operating characteristic analysis on the ultra-thin low temperature floor-heating system

Hualing ZHANG, Xiaopeng SONG

《结构与土木工程前沿（英文）》 2013年 第7卷 第2期   页码 127-132 doi: 10.1007/s11709-013-0200-3

摘要： Prefabricated ultra-thin radiant heating panel, as a new heating terminal type, is becoming a highlight in Yangtze River Valley area, China recently. However, there is a lack of operating characteristic research in this region, especially the energy consumption and operating mode are even less. To obtain these data, a heating system was set up in a duplex house in Chongqing. The test results show that the floor heating system could almost satisfy thermal comfort requirement at supply water temperature 45°C. But the preheating time was up to 4.5 h which was 1 h longer than that at supply water temperature 50°C. Meanwhile, the energy consumption at supply water temperature 50°C increased 0.10 Nm /h, and the operating efficiency decrease about 2.6% compared to those at water temperature 45°C. Considering both the thermal lag and operating efficiency, a reasonable suggestion was proposed in this paper. That was, the standard families which just stay home at night should adopt the interim mode of partial room with part time. And the supply water temperature should be properly raised during the preheating period and lowered down in the steady heating stage.

关键词： ultra-thin floor heating panel     the preheating time     thermal comfort     energy saving    

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A measurement system for thin elastohydrodynamic lubrication films

WANG Xuefeng, GUO Feng, YANG Peiran

《机械工程前沿（英文）》 2007年 第2卷 第2期   页码 193-196 doi: 10.1007/s11465-007-0032-8

摘要： An elastohydrodynamic lubrication (EHL) film measurement system using multi-beam interferometry is introduced in this paper. The measurement principle and the instrumentation are discussed. A simple and efficient method is suggested to obtain the fringe order of measured points. It is demonstrated that the presented measurement system can provide continuous measurement of lubricating films from nano to micro scales at a nano-level resolution, and can be used to investigate ultra-thin EHL films and tiny variations in EHL films.

关键词： instrumentation     continuous measurement     elastohydrodynamic lubrication     ultra-thin     measurement    

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面向未来低碳道路养护的超薄罩面功能性研究综述 Review

郭猛, 张瑞, 杜修力, 刘鹏飞

《工程（英文）》 2024年 第32卷 第1期   页码 83-99 doi: 10.1016/j.eng.2023.03.020

摘要：

截至2021年，中国公路养护总里程达到525万公里。超薄罩面作为最常用的路面养护技术之一，可以显著提高路面的经济效益和环境效益。为了促进超薄罩面的低碳发展，本文主要研究了超薄罩面几种功能性的作用机理及影响因素。首先，对超薄罩面的抗滑性能、降噪性能、抗车辙性能和抗裂性能进行了评价。结果表明，优质集料可使超薄罩面的抗滑和抗车辙性能提高5 %~20 %。优化后的级配及改性胶结料可将超薄罩面的噪音降低0.4~6.0 dB。高粘度改性胶结料可使超薄罩面混合料的抗车辙性能提高10 %~130 %。玄武岩纤维可使超薄罩面的抗裂性提升20 %以上。由于超薄罩面具有更薄的厚度及更好的道路性能，其基于性能的工程成本与传统罩面相比，可降低30 %~40 %。其次，研究了超薄罩面的几种环保功能，包括融雪除冰、废气降解和路面降温。由于超薄罩面的厚度较薄，有利于氯化物融雪材料向路表的扩散。因此，自融雪超薄罩面的融雪效果较好。此外，含有光催化材料的超薄罩面混合料可以分解20 %~50 %的尾气污染物。彩色超薄罩面最高能够将路面温度降低8.1 ℃。而含有热阻材料的超薄罩面的上下表面温差最高可达12.8 ℃。此外，本文总结了功能型超薄罩面在全世界的一些典型工程应用。本综述有助于研究人员更好地理解超薄罩面的功能性，同时可促进未来多功能低碳道路养护的实现。

关键词： 道路养护     超薄罩面     融雪除冰     尾气降解     路面降温     低碳    

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非线性弹性薄膜表面效应的尺寸相关性研究

黄殿武,连媛,李凯

《中国工程科学》 2006年 第8卷 第4期   页码 54-59

摘要：

在Mindlin假设的前提下，考虑了几何非线性条件及表面效应的影响，建立了纳米尺度下尺寸相关的板状各向同性弹性薄膜模型；从哈密尔顿变分原理出发，导出了薄膜的控制方程，用公式明确阐述了由表面张力引起的符合经典板理论且与薄膜变形相关的残余膜力和弯矩；通过微小尺寸薄膜弯曲的算例，说明了表面效应与薄膜厚度的相关性，当薄膜厚度等于或者小于其内禀尺度时，表面效应对薄膜厚度表现出很强的敏感性。

关键词： 弹性薄膜     几何非线性     表面效应     内禀尺度     尺度相关    

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Modeling nanostructured catalyst layer in PEMFC and catalyst utilization

Jiejing ZHANG, Pengzhen CAO, Li XU, Yuxin WANG

《化学科学与工程前沿（英文）》 2011年 第5卷 第3期   页码 297-302 doi: 10.1007/s11705-011-1201-1

摘要： A lattice model of the nanoscaled catalyst layer structure in proton exchange membrane fuel cells (PEMFC) was established by Monte Carlo method. The model takes into account all the four components in a typical PEMFC catalyst layer: platinum (Pt), carbon, ionomer and pore. The elemental voxels in the lattice were set fine enough so that each average sized Pt particulate in Pt/C catalyst can be represented. Catalyst utilization in the modeled catalyst layer was calculated by counting up the number of facets of Pt voxels where “three phase contact” are met. The effects of some factors, including porosity, ionomer content, Pt/C particle size and Pt weight percentage in the Pt/C catalyst, on catalyst utilization were investigated and discussed.

关键词： catalyst layer     PEM fuel cell     lattice model     Monte Carlo method     catalyst utilization    

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Theoretical analysis and experimental study on the influence of electric double layer on thin film lubrication

WANG Xin-jie, BAI Shao-xian, HUANG Ping

《机械工程前沿（英文）》 2006年 第1卷 第3期   页码 370-373 doi: 10.1007/s11465-006-0040-0

摘要： A new mathematical model for thin film lubrication is established by taking into account the effect of an electric double layer. In the present paper, experiments are carried out on a self-made tester. With a composite block and a

关键词： mathematical     account     electric     composite     lubrication    

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Exploration of the oxygen transport behavior in non-precious metal catalyst-based cathode catalyst layer

Shiqu CHEN, Silei XIANG, Zehao TAN, Huiyuan LI, Xiaohui YAN, Jiewei YIN, Shuiyun SHEN, Junliang ZHANG

《能源前沿（英文）》 2023年 第17卷 第1期   页码 123-133 doi: 10.1007/s11708-022-0849-1

摘要： High cost has undoubtedly become the biggest obstacle to the commercialization of proton exchange membrane fuel cells (PEMFCs), in which Pt-based catalysts employed in the cathodic catalyst layer (CCL) account for the major portion of the cost. Although non-precious metal catalysts (NPMCs) show appreciable activity and stability in the oxygen reduction reaction (ORR), the performance of fuel cells based on NPMCs remains unsatisfactory compared to those using Pt-based CCL. Therefore, most studies on NPMC-based fuel cells focus on developing highly active catalysts rather than facilitating oxygen transport. In this work, the oxygen transport behavior in CCLs based on highly active Fe-N-C catalysts is comprehensively explored through the elaborate design of two types of membrane electrode structures, one containing low-Pt-based CCL and NPMC-based dummy catalyst layer (DCL) and the other containing only the NPMC-based CCL. Using Zn-N-C based DCLs of different thickness, the bulk oxygen transport resistance at the unit thickness in NPMC-based CCL was quantified via the limiting current method combined with linear fitting analysis. Then, the local and bulk resistances in NPMC-based CCLs were quantified via the limiting current method and scanning electron microscopy, respectively. Results show that the ratios of local and bulk oxygen transport resistances in NPMC-based CCL are 80% and 20%, respectively, and that an enhancement of local oxygen transport is critical to greatly improve the performance of NPMC-based PEMFCs. Furthermore, the activity of active sites per unit in NPMC-based CCLs was determined to be lower than that in the Pt-based CCL, thus explaining worse cell performance of NPMC-based membrane electrode assemblys (MEAs). It is believed that the development of NPMC-based PEMFCs should proceed not only through the design of catalysts with higher activity but also through the improvement of oxygen transport in the CCL.

关键词： proton exchange membrane fuel cells (PEMFCs)     non-precious metal catalyst (NPMC)     cathode catalyst layer (CCL)     local and bulk oxygen transport resistance    

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Effect of catalyst layer mesoscopic pore-morphology on cold start process of PEM fuel cells

Ahmed Mohmed DAFALLA, Fangming JIANG

《能源前沿（英文）》 2021年 第15卷 第2期   页码 460-472 doi: 10.1007/s11708-021-0733-4

摘要： Water transport is of paramount importance to the cold start of proton exchange membrane fuel cells (PEMFCs). Analysis of water transport in cathode catalyst layer (CCL) during cold start reveals the distinct characteristics from the normal temperature operation. This work studies the effect of CCL mesoscopic pore-morphology on PEMFC cold start. The CCL mesoscale morphology is characterized by two tortuosity factors of the ionomer network and pore structure, respectively. The simulation results demonstrate that the mesoscale morphology of CCL has a significant influence on the performance of PEMFC cold start. It was found that cold-starting of a cell with a CCL of less tortuous mesoscale morphology can succeed, whereas starting up a cell with a CCL of more tortuous mesoscale morphology may fail. The CCL of less tortuous pore structure reduces the water back diffusion resistance from the CCL to proton exchange membrane (PEM), thus enhancing the water storage in PEM, while reducing the tortuosity in ionomer network of CCL is found to enhance the water transport in and the water removal from CCL. For the sake of better cold start performance, novel preparation methods, which can create catalyst layers of larger size primary pores and less tortuous pore structure and ionomer network, are desirable.

关键词： cold start     energy conversion     fuel cells     mesoscale morphology     tortuosity     water management    

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Thin-film composite forward osmosis membranes with substrate layer composed of polysulfone blended with

Baicang Liu,Chen Chen,Pingju Zhao,Tong Li,Caihong Liu,Qingyuan Wang,Yongsheng Chen,John Crittenden

《化学科学与工程前沿（英文）》 2016年 第10卷 第4期   页码 562-574 doi: 10.1007/s11705-016-1588-9

摘要： To advance commercial application of forward osmosis (FO), we investigated the effects of two additives on the performance of polysulfone (PSf) based FO membranes: one is poly(ethylene glycol) (PEG), and another is PSf grafted with PEG methyl ether methacrylate (PSf-g-PEGMA). PSf blended with PEG or PSf-g-PEGMA was used to form a substrate layer, and then polyamide was formed on a support layer by interfacial polymerization. In this study, NaCl (1 mol?L ) and deionized water were used as the draw solution and the feed solution, respectively. With the increase of PEG content from 0 to 15 wt-%, FO water flux declined by 23.4% to 59.3% compared to a PSf TFC FO membrane. With the increase of PSf-g-PEGMA from 0 to 15 wt-%, the membrane flux showed almost no change at first and then declined by about 52.0% and 50.4%. The PSf with 5 wt-% PSf-g-PEGMA FO membrane showed a higher pure water flux of 8.74 L?m ?h than the commercial HTI membranes (6–8 L?m ?h ) under the FO mode. Our study suggests that hydrophobic interface is very important for the formation of polyamide, and a small amount of PSf-g-PEGMA can maintain a good condition for the formation of polyamide and reduce internal concentration polarization.

关键词： thin-film composite     forward osmosis     amphiphilic copolymer     interfacial polymerization     poly(ethylene glycol)    

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Four kinds of capping materials for controlling phosphorus and nitrogen release from contaminated sediment using a static simulation experiment

《环境科学与工程前沿（英文）》 2022年 第16卷 第3期 doi: 10.1007/s11783-021-1463-x

摘要：

• Lanthanum modified bentonite (LMB) can effectively absorb phosphorus (P).

关键词： Sediment     Eutrophication     Thin-layer capping     Phosphorus     Nitrogen     Aluminum-based P-inactivation agent    

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指数型粘度修正模型及应用

曲庆文,王梅,柴山,姚福生

《中国工程科学》 2001年 第3卷 第10期   页码 53-58

摘要：

根据吸附理论和分子间能量的变化规律来确定表面相互作用程度，以此可定义吸附层，得出吸附层 厚度的分析计算式。吸附层厚度对研究薄膜润滑是最关键的因素，是薄膜与厚膜不同分析的关键点。根据分子 相互作用的基本理论及流体力学的基本定义得出指数型粘度修正的表达式，用于确定微小间隙内流体粘度的变 化规律，从而建立薄膜润滑理论模型，计算薄膜润滑轴承的特性。

关键词： 吸附层     粘度     薄膜润滑     轴承    

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无溶剂气相制备用于可持续分离过程的膜材料 Perspective

赵俊杰, Karen K. Gleason

《工程（英文）》 2020年 第6卷 第12期   页码 1432-1442 doi: 10.1016/j.eng.2020.05.002

摘要：

可用于水净化、碳捕集、生物燃料生产、燃料电池运行以及节能工业分离操作的可持续化工过程亟待发展下一代膜材料。膜的无溶剂制备不仅消除了有机溶剂的潜在环境问题，而且解决了脆弱聚合物基材的膨胀问题。此外，采用无溶剂气相沉积方法可以减少合成微孔材料[如金属有机骨架（MOF）]所需的活化步骤。本文综述了几种真空沉积工艺，包括引发式化学气相沉积（iCVD）、引发式等离子体增强化学气相沉积（iPECVD）、无溶剂气相沉积原位聚合（SLIP）、原子层沉积（ALD） 和分子层沉积（MLD）。这些无溶剂气相沉积方法在制备薄膜复合膜结构中的超薄选择层方面极具优势，而且能够保形地修饰纳米级孔道并精确调节孔径和孔内官能团。所制备的膜在气体分离、 纳滤、海水淡化和水/油分离等方面表现出颇具应用潜力的性能。因此，开发新型膜材料、放大可用于无溶剂气相沉积的高通量反应器将对化学工业产生巨大影响。

关键词： 膜分离     化学气相沉积     原子层沉积     分子层沉积     薄膜     金属有机骨架     聚合物     先进制造    

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A comprehensive assessment on the durability of gas diffusion electrode materials in PEM fuel cell stack

Arunkumar JAYAKUMAR

《能源前沿（英文）》 2019年 第13卷 第2期   页码 325-338 doi: 10.1007/s11708-019-0618-y

摘要： Polymer electrolyte membrane (PEM) fuel cell is the most promising among the various types of fuel cells. Though it has found its applications in numerous fields, the cost and durability are key barriers impeding the commercialization of PEM fuel cell stack. The crucial and expensive component involved in it is the gas diffusion electrode (GDE) and its degradation, which limits the performance and life of the fuel cell stack. A critical analysis and comprehensive understanding of the structural and functional properties of various materials involved in the GDE can help us to address the related durability and cost issues. This paper reviews the key GDE components, and in specific, the root causes influencing the durability. It also envisages the role of novel materials and provides a critical recommendation to improve the GDE durability.

关键词： PEM fuel cell     gas diffusion electrode(GDE)     gas diffusion layer(GDL)     membrane electrode assembly     durability     fuel cell catalyst    

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Fixturing technology and system for thin-walled parts machining: a review

《机械工程前沿（英文）》 2022年 第17卷 第4期 doi: 10.1007/s11465-022-0711-5

摘要： During the overall processing of thin-walled parts (TWPs), the guaranteed capability of the machining process and quality is determined by fixtures. Therefore, reliable fixtures suitable for the structure and machining process of TWP are essential. In this review, the key role of fixtures in the manufacturing system is initially discussed. The main problems in machining and workholding due to the characteristics of TWP are then analyzed in detail. Afterward, the definition of TWP fixtures is reinterpreted from narrow and broad perspectives. Fixture functions corresponding to the issues of machining and workholding are then clearly stated. Fixture categories are classified systematically according to previous research achievements, and the operation mode, functional characteristics, and structure of each fixture are comprehensively described. The function and execution mode of TWP fixtures are then systematically summarized and analyzed, and the functions of various TWP fixtures are evaluated. Some directions for future research on TWP fixtures technology are also proposed. The main purpose of this review is to provide some reference and guidance for scholars to examine TWP fixtures.

关键词： thin-walled part (TWP)     fixture     machining     fixture categories     fixture function    

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标题 作者 时间 类型 操作

Review of characterization and modeling of polymer electrolyte fuel cell catalyst layer: The blessing

Jun HUANG, Zhe LI, Jianbo ZHANG

期刊论文

Operating characteristic analysis on the ultra-thin low temperature floor-heating system

Hualing ZHANG, Xiaopeng SONG

期刊论文

A measurement system for thin elastohydrodynamic lubrication films

WANG Xuefeng, GUO Feng, YANG Peiran

期刊论文

面向未来低碳道路养护的超薄罩面功能性研究综述

郭猛, 张瑞, 杜修力, 刘鹏飞

期刊论文

非线性弹性薄膜表面效应的尺寸相关性研究

黄殿武,连媛,李凯

期刊论文

Modeling nanostructured catalyst layer in PEMFC and catalyst utilization

Jiejing ZHANG, Pengzhen CAO, Li XU, Yuxin WANG

期刊论文

Theoretical analysis and experimental study on the influence of electric double layer on thin film lubrication

WANG Xin-jie, BAI Shao-xian, HUANG Ping

期刊论文

Exploration of the oxygen transport behavior in non-precious metal catalyst-based cathode catalyst layer

Shiqu CHEN, Silei XIANG, Zehao TAN, Huiyuan LI, Xiaohui YAN, Jiewei YIN, Shuiyun SHEN, Junliang ZHANG

期刊论文

Effect of catalyst layer mesoscopic pore-morphology on cold start process of PEM fuel cells

Ahmed Mohmed DAFALLA, Fangming JIANG

期刊论文

Thin-film composite forward osmosis membranes with substrate layer composed of polysulfone blended with

Baicang Liu,Chen Chen,Pingju Zhao,Tong Li,Caihong Liu,Qingyuan Wang,Yongsheng Chen,John Crittenden

期刊论文

Four kinds of capping materials for controlling phosphorus and nitrogen release from contaminated sediment using a static simulation experiment

期刊论文

指数型粘度修正模型及应用

曲庆文,王梅,柴山,姚福生

期刊论文

无溶剂气相制备用于可持续分离过程的膜材料

赵俊杰, Karen K. Gleason

期刊论文

A comprehensive assessment on the durability of gas diffusion electrode materials in PEM fuel cell stack

Arunkumar JAYAKUMAR

期刊论文

Fixturing technology and system for thin-walled parts machining: a review

期刊论文