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Synthesis of phosphonated graphene oxide by electrochemical exfoliation to enhance the performance and durability of high-temperature proton exchange membrane fuel cells

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Journal of Energy Chemistry 2023年第1期76卷 448-458,I0011页

作者： Jianuo Chen Zunmin Guo Maria Perez-Page Yifeng Jia Ziyu Zhao Stuart M.Holmes Department of Chemical Engineering and Analytical Science University of ManchesterOxford RoadManchester M139PLUnited Kingdom Chemistry Research Laboratory Department of ChemistryUniversity of Oxford12 Mansfield RoadOxford OX13TAUnited Kingdom

The doping of functionalized graphene oxide(GO)in the membranes becomes a promising method for improving the performance of high-temperature proton exchange membrane fuel cells(HT-PEMFC).Phosphonated graphene oxide(PGO)with a P/O ratio of 8.5%was quickly synthesised by one-step electrochemical exfoliation based on a three-dimensiaonal(3D)printed reactor and natural graphite *** with the GO prepared by the two-step electrochemical exfoliation method,the PGO synthesized by the one-step electrochemical exfoliation can better improve the performance of the membrane-electrode-assembly(MEA)based on the polybenzimidazole(PBI)membrane in the *** doping of 1.5 wt%GO synthesised by electrochemical exfoliation with the 2-step method or reactor method in PBI increased the peak power density by 17.4%or 35.4%compared to MEA based on pure PBI membrane at 150℃,*** addition,the doping of PGO in PBI improves its durability under accelerated stress test(AST).

关键词： electrochemical exfoliation Phosphonated graphene oxide High-temperature fuel cells

One-Step Scalable Fabrication of Nitrogen and Chlorine Co-doped Graphene by electrochemical exfoliation for High-Performance Supercapacitors

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Transactions of Tianjin University 2024年第5期30卷 448-458页

作者： Qian Li Hu Zheng Binbin Liu Tianzhen Jian Wenqing Ma Caixia Xu Kai Wang Institute for Advanced Interdisciplinary Research(iAIR) School of Chemistry and Chemical EngineeringUniversity of JinanJinan 250022China Institute of Electrical Engineering Chinese Academy of SciencesBeijing 100190China

The stacking and aggregation of graphene nanosheets have been obstacles to their application as electrode materials for microelectronic *** study deploys a one-step,scalable,facile electrochemical exfoliation technique to fabricate nitrogen(N)and chlorine(Cl)co-doped graphene nanosheets(i.e.,N-Cl-G)via the application of constant voltage on graphite in a mixture of 0.1 mol/L H_(2)SO_(4)and 0.1 mol/L NH_(4)Cl without using dangerous and exhaustive *** introduction of Cl(with its large radius)and N,both with high electrical negativity,facilitates the modulation of the electronic structure of graphene and creation of rich structural defects in ***,in the as-constructed supercapacitors,N-Cl-G exhibits a high specific capacitance of 77 F/g at 0.2 A/g and remarkable cycling stability with 91.7%retention of initial capacitance after 20,000 cycles at 10 A/***,a symmetrical supercapacitor assembled with N-Cl-G as the positive and negative electrodes(denoted as N-Cl-G//N-Cl-G)exhibits an energy density of 3.38 Wh/kg at a power density of 600 W/kg and superior cycling stability with almost no capacitance loss after 5000 cycles at 5 A/*** study provides a scalable protocol for the facile fabrication of high-performance co-doped graphene as an electrode material candidate for supercapacitors.

关键词： Graphene electrochemical exfoliation Supercapacitor Nitrogen Chlorine

Synthesis of graphene materials by electrochemical exfoliation: Recent progress and future potential

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Carbon Energy 2019年第2期1卷 173-199页

作者： Fei Liu Chaojun Wang Xiao Sui Muhammad Adil Riaz Meiying Xu Li Wei Yuan Chen School of Chemical and Biomolecular Engineering The University of SydneySydneyNew South WalesAustralia Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application State Key Laboratory of Applied Microbiology Southern ChinaGuangdong Institute of MicrobiologyGuangdong Academy of SciencesGuangzhouChina

Synthesis of structurally controlled graphene materials is critical for realizing their practical *** electrochemical exfoliation of graphite has emerged as a simple method to produce graphene *** review examines research progress in the last 5 years,from 2015 to *** material synthesis methods generally have a trade‐off between increasing production yield and achieving better material property *** synthesis conditions for synthesizing pristine graphene,graphene oxide(GO),and graphene composites are significantly ***,in this review,we first discuss synthesis methods for graphene materials with high C/O ratios from four aspects:graphite electrodes,equipment engineering,electrolytes,and additional reduction ***,we survey synthesis methods for GO and examine how the pretreatment of the graphite electrodes,electrolytes,and operation parameters,such as applied voltages,electrolyte temperatures,and mechanical forces,affect the quality of ***,we summarize electrochemical exfoliation methods used to dope graphene materials,introduce covalent functional groups,incorporate various nanoparticles,and assembly of graphene *** all synthesis methods,we compare the properties of resulting graphene materials such as C/O ratios,lateral size,layer numbers,and quality characterized by Raman ***,we propose our perspectives on further *** hope this review stimulates more studies to realize the on‐demand production of graphene materials with desired properties using electrochemical exfoliation methods.

关键词： electrochemical exfoliation graphene graphene oxide graphite synthesis

Synthesis,characterization and life cycle assessment of electrochemically exfoliated KOH-activated holey graphene

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Frontiers of Environmental Science & Engineering 2023年第12期17卷 175-188页

作者： Fatemeh Mozaffarpour Nafiseh Hassanzadeh Ehsan Vahidi Faculty of Materials Science and Engineering K.N.Toosi University of TechnologyTehran ***Iran Department of Mining and Metallurgical Engineering Mackay School of Earth Sciences and EngineeringUniversity of NevadaRenoNV 89557USA

Graphene materials have drawn tremendous attention in recent *** formation of holes and pores on graphene sheets can provide transfer channels and facilitate the ion/electron transport *** this study,graphene nanosheets were prepared electrochemically,and then,they were used as the starting material for the preparation of holey graphene(HG)through the KOH activation *** weight ratio of initial electrochemically exfoliated graphene(EEG)to KOH was optimized according to the morphological features,BET surface area examination,graphene number of layers calculated from XRD patterns,and the ID/IG ratio obtained from Raman *** showed that increasing the KOH amount led to the achievement of higher values of ID/IG and surface area and less re-stacking of graphene sheets which occurs because of the heat treatment *** environmental burdens of the production routes for the preparation of EEG and HG were investigated by cradle-to-gate life cycle assessment(LCA).The LCA results of EEG production indicated that electricity with the contributions of 94%,91%,82%,and 75%of the total impact in four environmental categories,including fossil fuel depletion,ozone depletion,global warming,and smog was the main environmental *** the pore generation process,KOH was recognized as the biggest contributor(about 51%to 83%of the total impact)in six impact categories,including ozone depletion,non-carcinogenics,smog,global warming,carcinogenics,and eutrophication which could be attributed to its high consumption amount(21.9 kg).This work offers environmental considerations for the development of sustainable graphene materials.

关键词： Holey graphene electrochemical exfoliation Life cycle assessment(LCA) Environmental impact KOH activation

electrochemically exfoliated Ni-doped MoS_(2) nanosheets for highly efficient hydrogen evolution and Zn-H_(2)O battery

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Chinese Chemical Letters 2023年第1期34卷 159-163页

作者： Hao Wei Jincheng Si Libin Zeng Siliu Lyu Zhiguo Zhang Yange Suo Yang Hou School of Mechanical and Energy Engineering Zhejiang University of Science and TechnologyHangzhou 310027China Key Laboratory of Biomass Chemical Engineering of Ministry of Education College of Chemical and Biological EngineeringZhejiang UniversityHangzhou 310027China Institute of Zhejiang University-Quzhou Quzhou 324000China School of Metallurgy and Chemical Engineering Jiangxi University of Science and TechnologyGanzhou 341000China

Thanks to tunable physical and chemical properties,two-dimensional(2D)materials have received intensive interest,endowing their excellent electrocatalytic performances for applications in energy ***,their catalytic activities are largely determined by poor adsorption energy and limited active edge ***,a one-step electrochemical exfoliation strategy was developed to fabricate 2D Ni-doped MoS_(2)nanosheets(Ni-EX-MoS_(2))with a lateral size of500 nm and thickness of3.5 *** from high electrical conductivity and abundant exposing active sites,Ni-EX-MoS_(2)catalyst displayed an admirable performance for electrochemical hydrogen evolution reaction(HER)with a low overpotential of 145 m V at 10 m A/cm^(2)as well as a small Tafel slope of 89 m V/dec in alkaline media,which are superior to those of the most reported MoS_(2)-based *** formed Ni species with tuning electronic structure played a crucial role as primary active center of Ni-EX-MoS_(2),as well as the forming stable 1T/2H phase MoS_(2)interface demonstrated a synergistic effect on electrocatalytic HER ***,Ni-EX-MoS_(2)was employed as a cathode electrode for alkaline Zn-H_(2)O battery,which displayed a high power density of 3.3 m W/cm^(2)with excellent *** work will provide a simple and effective guideline for design of electrochemically exfoliated transition metal-doped MoS_(2)nanosheets to inspire their practical applications in energy catalytic and storage.

关键词： electrochemical exfoliation Ni doping MoS_(2) Hydrogen evolution reaction Zn-H_(2)O battery

Unlocking the charge doping effect in softly intercalated ultrathin ferromagnetic superlattice

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eScience 2023年第3期3卷 105-114页

作者： Liang Hu Bingzhang Yang Zhipeng Hou Yangfan Lu Weitao Su Lingwei Li Key Laboratory of Novel Materials for Sensor of Zhejiang Province College of Materials and Environmental EngineeringHangzhou Dianzi UniversityHangzhou310018PR China State Key Lab of Silicon Materials School of Materials Science and EngineeringZhejiang UniversityHangzhou310027PR China South China Academy of Advanced Optoelectronics South China Normal UniversityGuangzhou510006PR China

The electrolyte-assisted exfoliation strategy is widely employed to synthesize ultrathin two-dimensional(2D)***,spins in 2D magnets are susceptible to the electrolyte due to the underlying charge doping ***,it is crucial to understand and trace the doping process during the delamination of 2D *** the prototype Fe_(3)GeTe_(2),we utilized soft organic cations to exfoliate the bulk and obtain a freestanding organ-ic–inorganic hybrid superlattice with a giant electron doping effect as high as 6.9×10^(14)/cm^(2)(~1.15 electrons per formula unit).A remarkable ferromagnetic transition exceeding 385 K was revealed in these superlattices,together with unique anisotropic saturation *** doping enhanced the in-plane electron–phonon coupling and thus optimized originally poor indirect double-exchange scenario for spin *** emerging vertical magnetization shift phenomenon served to evaluate the uniformity of charge *** above findings provide a new perspective for understanding the role of parasitic charge in 2D magnetism.

关键词： Van der waals magnet electrochemical exfoliation Hybrid superlattice Electron doping Exchange bias Spintronics

electrochemically intercalated intermediate induced exfoliation of few-layer MoS from molybdenite for long-life sodium storage

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Science China Materials 2021年第1期64卷 115-127页

作者： Honglei Shuai Jiayang Li Feng Jiang Xianan Zhang Laiqiang Xu Jiugang Hu Hongshuai Hou Guoqiang Zou Wei Sun Huigao Duan Junhua Hu Xiaobo Ji State Key Laboratory for Powder Metallurgy College of Chemistry and Chemical EngineeringCentral South UniversityChangsha410083China School of Minerals Processing and Bioengineering Central South UniversityChangsha410083China State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body College of Mechanical and Vehicle EngineeringHunan UniversityChangsha410082China College of Materials Science and Engineering Zhengzhou UniversityZhengzhou450001China

Two-dimensional(2D) molybdenum disulfide(MoS2 ) holds significant promise as an energy storage material, whereas the exfoliation of MoS2 into few-layer from natural molybdenites remains a challenge. An efficient electrochemical strategy was proposed for the preparation of fewlayer MoS2 through cationic intercalation. Few-layer MoS2 without the impurity phases was obtained with high yield through Raman mapping analysis, and the intermediate(TBA+)xMoS2x- was captured by in-situ Raman. Note that the charge transport kinetics of the exfoliated few-layer MoS2 was further enhanced by the introduction of graphene, which could efficiently enhance the Na+diffusion mobility, alleviate the volume change of MoS2 and stabilize the reaction products. Commendably, the exfoliated MoS2 /graphene hybrid shows a reversible specific capacity of 642.8 mA h g-1 at 0.1 A g-1, superior rate performance(447.8 and 361.9 mA h g-1 at 1 and 5 A g-1, respectively) and remarkable long-cycle stability with 328.7 mA h g-1 at 1 A g-1 after 1000 cycles for sodium-ion batteries(SIBs). Therefore, this efficient electrochemical exfoliation method can be driven to prepare other few-layer 2D materials for SIBs.

关键词： electrochemical exfoliation MoS2 in-situ Raman high performance sodium-ion batteries