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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

Bifunctional interstitial phosphorous doping strategy boosts platinum-zinc alloy for efficient ammonia oxidation reaction and hydrogen evolution reaction

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Nano Research 2024年第3期17卷 1182-1189页

作者： Tianqi Yu Kexin Tan Jia Wu Yongjin Zou Shibin Yin guangxi key laboratory of Electrochemical Energy materials School of Chemistry and Chemical EngineeringGuangxi UniversityNanning 530004China guangxi key laboratory of Information materials Guilin University of Electronic TechnologyGuilin 541004China

It is still a lack of bifunctional catalysts for ammonia oxidation reaction(AOR)and hydrogen evolution reaction(HER)due to their different reaction *** this work,P is doped into PtZn alloy by calcination with NaH_(2)PO_(2) as P source to induce the lattice tensile strain of Pt and the electronic interaction between P and Zn,which optimizes the AOR and HER activity *** sample with the optimal P content can drive the AOR peak current density of 293.6 mA·mgPt^(-1),which is almost 2.7 times of *** HER,the overpotential at^(-1)0 mA·cm^(-2) is only 23 mV with Tafel slope of 34.1 mV·dec^(-1).Furthermore,only 0.59 V is needed to obtain 50 mA·mgPt^(-1) for ammonia electrolysis under a two-electrode ***,this work shows an ingenious method to design bifunctional catalysts for ammonia electrolysis.

关键词： PtZn alloy phosphorous doping ammonia oxidation reaction hydrogen evolution reaction bifunctional catalyst

Solvent extraction of scandium from leaching solution of red mud roasted with ammonium sulfate using D2EHPA/TBP

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Journal of Rare Earths 2024年第10期42卷 1943-1949页

作者： Fucheng Li Xinsheng Li Lei Shi Xiang Li Duoqiang Liang Yuezhou Wei Toyohisa Fujita School of Resources Environment and MaterialsGuangxi University State key laboratory of Featured Metal materials and Life-cycle Safety for Composite structures Guangxi University School of Nuclear Science and Technology University of South China

Red mud is an important secondary resource for scandium *** red mud leaching solution containing scandium in this study was derived from environmentally friendly ammonium sulfate roasting and water leaching process.A synergistic extraction with a mixture of di（2-ethylhexyl） phosphate acid（D2EHPA） and tributyl phosphate（TBP） for recovery of scandium from red mud leaching solution is *** effects of D2EHPA concentration,H2SO4concentration,rare earth elements,dosage of TBP,phase ratio（A/O）,contact time and H2O2concentration on scandium extraction were *** results show that more than 99% scandium is extracted under the optimal conditions while Fe,Al,Ti,Ca and rare earth elements（Ce,Y,La,Nd,Er,etc.） are hardly *** stripping efficiency of Sc reaches above 92.37% under the optimal stripping conditions of 5 mol/L NaOH with an A/O of 1 at 90℃ for 30 *** proposed technology could provide an effective method for extraction of scandium from red mud leaching solution.

关键词： D2EHPA/TBP Rare earths Red mud leaching solution Scandium Solvent extraction

Optical trapping capability of tornado circular Pearcey beams

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Chinese Physics B 2024年第5期33卷 401-407页

作者：刘娜娜唐晓莹刘舜禹梁毅 guangxi key laboratory for Relativistic Astrophysics Center on Nanoenergy ResearchGuangxi Colleges and Universities Key Laboratory of Blue Energy and Systems IntegrationSchool of Physical Science and TechnologyGuangxi UniversityNanning 530004China State key laboratory of Featured Metal materials and Lifecycle Safety for Composite structures Nanning 530004China

We systemically investigate optical trapping capability of a kind of tornado waves on Rayleigh *** tornado waves are named as tornado circular Pearcey beams(TCPBs)and produced by combining two circular Pearcey beams with different *** theoretical exploration delves into various aspects,including the propagation dynamics,energy flux,orbital angular momentum,trapping force,and torque characteristics of *** results reveal that the orbital angular momentum,trapping force,and torque of these beams can be finely tuned through the judicious manipulation of their topological charges(l_(1)and l_(2)).Notably,we observe a precise control mechanism wherein the force diminishes with|l_(1)+l_(2)|and|l_(1)-l_(2)|,while the torque exhibits enhancement by decreasing solely with|l_(1)+l_(2)|or increasing with|l_(1)-l_(2)|.These results not only provide quantitative insights into the optical trapping performance of TCPBs but also serve as a valuable reference for the ongoing development of innovative photonic tools.

关键词： trapping capability tornado beams autofocusing

Transfer matrix method for free and forced vibrations of multi-level functionally graded material stepped beams with different boundary conditions

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Applied Mathematics and Mechanics(English Edition) 2024年第6期45卷 983-1000页

作者： Xiaoyang SU Tong HU Wei ZHANG Houjun KANG Yunyue CONG Quan YUAN School of Civil engineering and Architecture Guangxi UniversityNanning 530004China Scientific Research Center of engineering Mechanics Guangxi UniversityNanning 530004China State key laboratory of Featured Metal materials and Life-Cycle Safety for Composite structures Guangxi UniversityNanning 530004China

Functionally graded materials(FGMs)are a novel class of composite materials that have attracted significant attention in the field of engineering due to their unique mechanical *** study aims to explore the dynamic behaviors of an FGM stepped beam with different boundary conditions based on an efficient solving *** the assumptions of the Euler-Bernoulli beam theory,the governing differential equations of an individual FGM beam are derived with Hamilton’s principle and decoupled via the separation-of-variable ***,the free and forced vibrations of the FGM stepped beam are solved with the transfer matrix method(TMM).Two models,i.e.,a three-level FGM stepped beam and a five-level FGM stepped beam,are considered,and their natural frequencies and mode shapes are *** demonstrate the validity of the method in this paper,the simulation results by ABAQUS are also *** this basis,the detailed parametric analyses on the frequencies and dynamic responses of the three-level FGM stepped beam are carried *** results show the accuracy and efficiency of the TMM.

关键词： transfer matrix method(TMM) free vibration forced vibration functionally graded material(FGM) stepped beam

Hybrid assembly of conducting nanofiber network for ultra-stretchable and highly sensitive conductive hydrogels

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Journal of materials Science & Technology 2024年第2期169卷 1-10页

作者： Yalei Wang Shulong Zeng Shaohong Shi Yuheng Jiang Zhiwei Du Bingzhen Wang Xiurong Li State key laboratory of Featured Metal materials and Life-cycle Safety for Composite structures School of ResourcesEnvironment and MaterialsGuangxi UniversityNanning 530004China State key laboratory of Polymer materials engineering Polymer Research Institute of Sichuan UniversitySichuan UniversityChengdu 610065China

Conductive hydrogels have attracted extensive attention owing to their promising application prospects in flexible and wearable ***,achieving both high sensitivity and mechanical robustness remains ***,a novel and versatile conductive hydrogel based on the hybrid assem-bly of conductive cellulose nanofiber(CNF)networks has been designed and *** by the templating effect of CNFs and stabilizing effect of negatively charged poly(styrene sulfonate)(PSS),conducting polymer poly(3,4-ethylenedioxythiophene)(PEDOT)was self-organized into three-dimensional nanostructures which constructed a robust conductive network after in-situ oxidative *** unique structure derived from CNF bio-template endowed polyacrylamide(PAM)hydrogels with improved electrical conductivity and excellent mechanical *** a result,the as-fabricated CNF/PEDOT:PSS/PAM hydrogel exhibited an ultimate tensile strain of 1881%and toughness of 3.72 MJ/m^(3),which were 4.07 and 8.27 times higher than the CNF-free hydrogel,*** significantly,the resultant hydrogel sensor showed highly desirable sensing properties,including remarkable sensing range(1100%),high gauge factor(GF=5.16),fast response time(185 ms),and commendable durability,as well as good ***,the hydrogel sensor was able to distinguish subtle physiological activities including phonation and facial expression,and monitor large human body motions such as finger flexion and elbow ***,it was feasible to integrate the strain sensor on the joints of robots to recognize complicated machine motion signals,showing potential in advanced human-machine interactions.

关键词： Strain sensor Cellulose nanofibers PEDOT:PSS Conductive hydrogel Templating method

Highly effective design of high GFA alloys with different metalbased and various components by machine learning

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Science China(Technological Sciences) 2024年第5期67卷 1431-1442页

作者： TANG YiChuan HE YiFan FAN ZhuoQun WANG ZhongQi TANG ChengYing guangxi key laboratory for Informational materials School of Materials Science and EngineeringGuilin University of Electronic TechnologyGuilin541004China

The glass-forming ability(GFA)is of great significance for the development of novel functional metal-based metallic *** this study,seven popular machine learning(ML)algorithms were employed to design novel M-based(M=Fe,Co,Ni,Ti,Zr,and rare earth metal(RE))and X-component(X=2,3,4,5,6,and>6)alloys with excellent GFA.A GFA containing 6957 data points with structural analysis was *** engineering was used to analyze the importance and correlation of *** algorithms were utilized for GFA prediction,revealing that Xtreme Gradient Boosting Trees exhibited the strongest predictive capability,achieving a high accuracy of 94.0%,a true positive rate of 97.6%,and a root mean squared error of 0.3705 across the entire ***,the GFA of ternary to hexahydroxy alloys based on Fe,Co,Ni,Zr,Ti,and Y was predicted using all possible compositions generated through ***,a series of alloys with good GFA was successfully designed and *** present work suggests that the proposed ML method can be utilized to design novel multiple-M-based amorphous alloys with high GFA.

关键词： machine learning amorphous alloy feature engineering materials design glass forming ability

A ratiometric optical thermometer with dual-color emission based on Eu^(2+)-doped CsCu_(2)I_(3) microcrystals

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Journal of Rare Earths 2024年第8期42卷 1429-1436,I0001页

作者： Xiaorong Li Ge Gao Kaiyu Wang Zhaoqiong Chen Zejiang Gao Qingyong Qin Li Chen Bingsuo Zou State key laboratory of Featured Metal materials and Life-cycle Safety for Composite structures School of Physical Science and TechnologyGuangxi UniversityNanning530004China School of Resources Environments and MaterialsGuangxi UniversityNanning530004China

With the increasing demand for non-co ntact fluorescence intensity ratio-based optical thermometry,novel phosphor materials with high-efficiency,dual-emitting centers,and differentiable temperature sensitivity are highly desired,In this wo rk,rare earth Eu^(2+) ions were incorporated Wnto CsCu_(2)I_(3) microcrystals by solidstate reaction,Under a single UV excitation,the as-synthesized samples exhibit two emissions:452 nm blue emission from the 5d→4f transition of Eu^(2+)and 582 nm yellow emission from self-trapped exciton e mission of CsCu_(2)I_(3).The photoluminescence quantum yield reaches to 50%,The dual-band emission of Eu^(2+)-doped CsCu_(2)I_(3) shows different temperature responses in the range of 260-360 *** on fluorescence intensity ratio technology,the maximum absolute sensitivity and re Iative sensitivity are 0.091 K^(-1)(at 360 K) and 2.60%/K(at 260 K),*** results suggest that Eu^(2+)-doped GsCu_(2)I_(3) could be a good candidate for highly sensitive optical thermometer.

关键词： CsCu_(2)I_(3) Eu^(2+)-doping Fluorescence intensity ratio Optical thermometer Rare earths

Temperature-dependent self-trapped exciton emission in Cu(I) doped zinc-based metal halides from well-resolved excited state structures

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Nano Research 2024年第8期17卷 7768-7775页

作者： Yunlong Bai Shuai Zhang Nengneng Luo Bingsuo Zou Ruosheng Zeng State key laboratory of Featured Metal materials and Life-cycle Safety for Composite structures School of Physical Science and TechnologyGuangxi UniversityNanning 530004China

Zero-dimensional metal halides are of unique structures and tunable photoluminescence properties,showing great potential applications such as light-emitting diodes(LEDs)and ***,we successfully synthesized Cu^(+)doped(MA)_(2)ZnCl_(4)metal halides by a slow evaporation solvent *** introduction of Cu^(+)results in sky-blue self-trapped exciton emission in(MA)_(2)ZnCl_(4) at 486 nm at room temperature,and a photoluminescence quantum yield is as high as 54.9%.Interestingly,at low temperatures,Cu^(+)-doped(MA)_(2)ZnCl_(4) exhibits two emission peaks located at 482 and 605 nm,*** temperaturedependent dual emission indicates two excited state structures that exist on the triplet excited-state potential energy *** addition,the temperature sensor we fitted has good performance(Sr=1.65%·K^(−1)),which is the first attempt in Cu^(+) doped Znbased metal *** work enriches the family of sky-blue metal halides and provides a promising strategy for building skyblue LEDs.

关键词： sky-blue emission self-trapped exciton metal halides excited state structures temperature sensor