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Structure-dependent electrocatalytic activity of La_(1-x)SrxMnO_3 for oxygen reduction reaction

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Science China Chemistry 2015年第5期58卷 871-878页

作者： Guangjin Wang Tian Xu Sheng Wen mu pan College of Chemistry and Materials Science Hubei Engineering University State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Hubei Provincial Key Laboratory of Fuel Cell

The electrocatalytic activity toward oxygen reduction reaction is studied on the perovskite oxide La~_xbrxMnt）3, as preparea under different firing temperatures. X-ray diffraction shows that three different crystal phases featuring tetragonal, cubic, and orthorhombic symmetries form with increasing crystallinities. The electrocatalytic activity is characterized by cyclic voltam- metry and linear sweeping voltammetry for the three phases of La1-xSrxMnO3. We find that the tetragonal phase has the best catalytic activity among the three crystal phases, with the largest onset potential of 0.147 V. The synergistic effect between the volume per unit cell and crystallinity is indicated to account for the good catalytic activity of the tetragonal phase.

关键词： perovskite oxide La1-xSrxMnO3 crystal phase crystallinity oxygen reduction reaction

Accelerated life-time test of MEA durability under vehicle operating conditions in PEM fuel cell

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Frontiers in Energy 2017年第3期11卷 326-333页

作者： Tian TIAN Jianjun TANG Wei GUO mu pan State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Hubei Provincical Key Laboratory of Fuel Cell Wuhan University of Technology Wuhan 430070 China

In this paper, a novel accelerated test method was proposed to analyze the durability of MEA, considering the actual operation of the fuel cell vehicle. The proposed method includes 7 working conditions： open circuit voltage （OCV）, idling, rated output, overload, idling-rated cycle, idling-overload cycle, and OCV-idling cycle. The experimental results indicate that the proposed method can effectively destroy the MEA in a short time （165 h）. Moreover, the degradation mechanism of MEA was analyzed by measuring the polarization curve, CV, SEM and TEM. This paper may provide a new research direction for improving the durability of fuel cell.

关键词： polymer electrolyte membrane fuel cell accelerated life-time test load cycling test durability

Facile Oxygen-promoted Synthesis of Cu,N Co-doped Carbon Composites for Oxygen Reduction

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Journal of Wuhan University of Technology(Materials Science) 2021年第6期36卷 796-803页

作者： LIU Qianqian GUO Wei pan mu TU Wenmao Hubei Key Laboratory of Fuel Cell Wuhan University of TechnologyWuhan 430070China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China

A new strategy to fabricate oxygen-promoted Cu,N co-doped carbon(OP-CuN@C)composites is *** strategy consists of only two simple steps:chemical polymerization and high temperature *** measurements were conducted to investigate the catalytic activity and mechanism of ORR on the resulting *** the electrochemical results indicate that OP-CuN@C exhibits the best ORR catalytic *** ORR onset potential of OP-CuN@C is slightly lower than that of commercial Pt/C *** good performance is attributed to the large specific surface area,high content of heteroatoms(pyridinic,graphitic nitrogen,and oxygen atom)and synergistic effect between divalent copper and nitrogen dopant.

关键词： oxygen reduction reaction oxygen promotion OP-CuN@C chemical polymerization approach high temperature carbonized method

Influence of pore size optimization in catalyst layer on the mechanism of oxygen transport resistance in PEMFCs

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Progress in Natural Science:Materials International 2020年第6期30卷 839-845页

作者： Shumeng Guan Fen Zhou Jinting Tan mu pan State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Hubei Provincial Key Laboratory of Fuel Cells Wuhan University of Technology

In PEMFC, the oxygen transport resistance severely hinders the cell from achieving high performance. In this paper, pore-forming agent was used to optimize the pore size distribution of the catalyst layer(CL), and to study its effect on the mechanism of oxygen transport resistance, including molecular diffusion resistance, Knudsen diffusion resistance, and local O2resistance in CL. The results showed that with the pore formation the cell performance had a significant improvement at high current density, mainly due to its better oxygen transport properties, especially under low platinum conditions. The addition of pore-forming agent moved the pore diameter toward a larger pore diameter with a range from 70 to 100 nm, and also obtaining a higher cumulative pore volume. It was found that the increase of the cumulative pore volume and larger pore size were conducive to the diffusion of oxygen molecules in CL, and the resistance caused by which was the dominant part in total transport resistance. Further tests indicated that the improvement of molecular diffusion resistance was much larger than that of Knudsen diffusion resistance in the catalyst layer after pore formed. In addition, the optimized pore structure will also get a higher number of effective pores, which resulted in an increased effective area of the ionomer on the Pt surface. The higher effective area of the ionomer was particularly beneficial for the reduction of local O2resistance with low Pt loading.

关键词： Pore size optimization Pore-forming agent Oxygen transport resistance PEMFC

Pure Detail Feature Extraction Network for Visible-Infrared Re-Identification

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Intelligent Automation & Soft Computing 2023年第8期37卷 2263-2277页

作者： Jiaao Cui Sixian Chan pan mu Tinglong Tang Xiaolong Zhou Zhejiang University of Technology Hangzhou310023China Hubei Key Laboratory of Intelligent Vision Based Monitoring for Hydroelectric Engineering The College of Computer and InformationChina Three Gorges UniversityYichang443002China The College of Electrical and Information Engineering Quzhou UniversityQuzhou324000China

Cross-modality pedestrian re-identification has important appli-cations in the field of *** to variations in posture,camera per-spective,and camera modality,some salient pedestrian features are difficult to provide effective retrieval ***,it becomes a challenge to design an effective strategy to extract more discriminative pedestrian *** many effective methods for detailed feature extraction are proposed,there are still some shortcomings in filtering background and modality *** further purify the features,a pure detail feature extraction network(PDFENet)is proposed for *** includes three modules,adaptive detail mask generation module(ADMG),inter-detail interaction module(IDI)and cross-modality cross-entropy(CMCE).ADMG and IDI use human joints and their semantic associations to suppress background noise in *** guides the model to ignore modality noise by generating modality-shared feature ***,ADMG generates masks for pedestrian details based on pose *** are used to suppress background information and enhance pedestrian detail ***,IDI mines the semantic relations among details to further refine the ***,CMCE cross-combines classifiers and features to generate modality-shared feature labels to guide model *** ablation experiments as well as visualization results have demonstrated the effectiveness of PDFENet in eliminating background and modality *** addition,comparison experi-ments in two publicly available datasets also show the competitiveness of our approach.

关键词： Person re-identification multimedia image retrieval

Effects of Cracks on the Mass Transfer of Polymer Electrolyte Membrane Fuel Cell with High Performance Membrane Electrode Assembly

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Journal of Wuhan University of Technology(Materials Science) 2021年第3期36卷 318-330页

作者： SHI Jinrong ZHAN Zhigang ZHANG Di YU Yuan YANG Xiaoxiang HE Luyan pan mu Foshan Xianhu Laboratory Foshan 528000China State Key Laboratory of Advanced Technology for Materials Synthesis and Pro-cessing Wuhan University of TechnologyWuhan 430070China

A two-dimensional geometric model is developed for a polymer electrolyte based on the liquid water penetration mechanism in the membrane electrode assemblies under the action of capillary *** effects of the diameter,number,and distribution of cracks in the micro-pore layers(MPLs)of the modeled MEA on the performance of the PEMFC are simulated to investigate the influence of mass transfer across the *** results indicate that liquid water in the catalyst layer(CL)of the MEA can be discharged to gas channels through the cracks in MEA under the action of capillary pressure,thereby alleviating the flooding in the CL and enhancing the diffusion of oxygen to the *** the proportion of the total area of cracks in the active area of the MEA was 8%-12%,crack diameter was 20-30μm,and cracks were distributed *** with and without cracks were prepared,fuel cells were assembled,and their performance was *** effects of cracks on mass transfer were then *** study helps prepare MEAs with controllable cracks.

关键词： PEMFC MEA cracking liquid saturation oxygen concentration transfer

Synthesis and Evaluation on Performance of Hydrogen Storage of multi-Walled Carbon Nanotubes Decorated with Platinum

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Journal of Wuhan University of Technology(Materials Science) 2003年第3期18卷 33-35页

作者：木士春 State Key Labof Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology

By means of chemical reduction,nanoparticles of platinum were deposited on the surface of multi walled carbon nanotubes (MWCNTs).The performance of hydrogen storage of as prepared MWCNTs decorated with platinum was *** results indicate that:(1) Hydrogen uptake is more quick and intense for decorated MWCNTs than that for not decorated ones at 10.931MPa and room *** saturation of hydrogen uptake of the former only lasts about 30min,while the latter needs about 150 min;(2) The amount of hydrogen uptake of decorated MWCNTs is about 1.13wt%, which is larger than that of not decorated ones(about 0.54wt%);(3) However,more than 37% hydrogen absorbed by decorated MWCNTs is chemisorbed.

关键词： nanoscale platinum carbon nanotubes hydrogen storage materials of energy resource Pt/carbon nanotubes catalysts

Promotion of catalytic activity for methanol electro-oxidation on CoPc-Pt/C co-catalysts

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Chinese Science Bulletin 2009年第6期54卷 1032-1036页

作者： WU JingJie XU YiMin pan mu MA WenTao TANG HaoLin State Key Laboratory of Advanced Technology for Materials Synthesis and Progressing Wuhan University of Technology Wuhan 430070 China

The catalytic activity for methanol electro-oxidation on CoPc-Pt/C co-catalysts, prepared by impregna-tion method, was studied in details through electrochemical methods. Cyclic voltammetry (CV) result demonstrates that CoPc has higher forward anodic peak current density and jf / jb value (forward anodic peak current density/backward anodic peak current density) than Pt/C. Chronoamperometry (CA) analysis indicates that CoPc-Pt/C exhibits both excellent transient current density and stable current density for methanol electro-oxidation compared with Pt/C. Two main mechanisms related to the pro-motion of catalytic activity are as follows: CoPc-Pt/C has the activity of tolerance to carbonaceous in-termediates, thus inhibiting the self-poisoning of catalysts; CoPc-Pt/C owns prominent intrinsic cata-lytic activity indicated by the apparent activation energy for methanol oxidation on CoPc-Pt/C, which is 18 kJ/mol, less than that on Pt and PtRu catalysts as reported.

关键词：甲醇电氧化催化活性酞菁钴催化剂铂电流密度炭合作

Degradation of Silicone Rubbers in Fenton's Reagents

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Journal of Wuhan University of Technology(Materials Science) 2018年第4期33卷 793-796页

作者：吴凡李克 ZHANG Qinglian ZHANG Haining CHEN Yanan pan mu YAN Xinping State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology National Engineering Research Center for Waterway Transport Safety Intelligent Transport Systems Research Center Wuhan University of Technology Hubei Key Laboratory of Fuel Cells Wuhan University of Technology

Gaskets are applied in PEMFCs（proton exchange membrane fuel cells） to keep reactant gases and liquid within their respective regions, which are of great significance for the both sealing and electrochemical performance of fuel cells during the long-term operation. In this study, the degradation of silicone rubbers, often selected as seals in PEMFCs, in Fenton＇s reagents with different H_2O_2 concentrations was investigated. The changes in chemical properties, mechanical behavior and surface morphology of the samples were studied before and after exposure to the test environment over time. It is found that increasing H_2O_2 concentration will degrade the rubbers more severely. The experimental results elucidate the degradation mechanism of silicone rubbers in Fenton＇s reagents and the influence of H_2O_2 in the degradation process.

关键词： silicone rubbers PEMFCs seal degradation Fenton's reagents