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One-step exfoliation and deprotonation of ANF/BNNS suspension for constructing 3D vertically aligned skeleton in epoxy-based thermal management composites

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Science China(Technological Sciences) 2022年第11期65卷 2675-2686页

作者： HAN GaoJie XUE PeiWen CAI ZhengHao FENG YueZhan LIU ChunTai SHEN ChangYu Key Laboratory of Materials Processing and Mold Ministry of Education National Engineering Research Center for Advanced Polymer Processing TechnologyZhengzhou UniversityZhengzhou450002China

Two-dimensional(2D)boron nitride nanosheet(BNNS)is promising in polymer-based thermal management materials(TMMs)by pre-constructing three-dimensional(3D)thermally conductive skeleton,but it yet suffers from the challenges of higheffective exfoliation and affinitive compatibility with *** this work,we developed a one-step exfoliation and deprotonation approach by the high-effective ball milling technique to prepare aramid nanofiber(ANF)/BNNS *** the strong collision/shear effect of ball-milling,micron-level h BN sheets were exfoliated into smaller and thinner BNNS with edge functional groups,meanwhile,poly-p-phenylene terephthalamide(PPTA)fibers were split into ANF by dissociating the intermolecular hydrogen *** importantly,both the exfoliation and deprotonation could be accelerated by each other to achieve a 100%yield of ANF/BNNS suspension with strong hydrogen/covalent bonding interactions between ***,the prepared ANF/BNNS suspension was used to construct 3D vertically aligned ANF/BNNS skeleton by the unidirectional freezing *** obtained epoxy-based composite(EP/ANF/BNNS)revealed excellent thermal conductivity of 2.41 W m^(-1)K^(-1) at 14.9 vol%BNNS loading due to the vertically oriented heat conduction paths and low interfacial thermal resistance in the ***,EP/ANF/BNNS composite showed high thermal stability and extraordinary fire retardancy with dramatically decreased heat release rate(265 W g^(-1)) and total heat release(20.6 kJ g^(-1)).Therefore,this work demonstrates a high-efficient one-step ball-milling exfoliation and deprotonation technique for preparing ANF/BNNS suspension,which reveals an enormous potential in preparing advanced TMMs by constructing 3D thermally conductive skeletons.

关键词： boron nitride nanosheet aramid nanofiber ball milling exfoliation thermal management composites

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synthesis of ZSM-22/SAPO-11 composite molecular sieve-based catalysts with small crystallites and superior n-alkane hydroisomerization performance

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Petroleum Science 2023年第4期20卷 2585-2595页

作者： Xue-Man Wang Cheng-Long Wen Yu Fan State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing102249China Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology Advanced Catalysis and Green Manufacturing Collaborative Innovation CenterSchool of Petrochemical EngineeringChangzhou UniversityChangzhouJiangsu213164China

To improve oil quality,ZSM-22/SAPO-11 composite molecular sieves were synthesized by adding ZSM-22 into a synthetic gel of SAPO-11 for n-decane *** mass ratios of ZSM-22/(ZSM-22+SAPO-11)in the composite molecular sieves were optimized and the optimal ZSM-22/SAPO-11 composite(ZS-9)was *** electrostatic repulsions between the ZSM-22 precursors and the SAPO-11 crystalline nuclei produced small ZSM-22 and SAPO-11 crystallites in ZS-9,which increased the specific surface area and mesopore volume and thereby exposed more acid *** comparison with conventional SAPO-11,ZSM-22 and their mechanical mixture,ZS-9 with smaller crystallites and the optimal medium and strong Brønsted acid centers(MSBAC)content displayed a higher yield of branched C_(10) isomers(81.6%),lower cracking selectivity(11.9%)and excellent *** correlation between the i-C_(10) selectivity and the MSBAC density of molecular sieves indicated that the selectivity for branched C_(10) isomers first increased and then decreased with increasing MSBAC density on the molecular sieves,and the maximum selectivity(87.7%)occurred with a density of 9.6×10^(−2)μmol m^(−2).

关键词： ZSM-22/SAPO-11 composite molecular sieves Medium and strong brønsted acid centers Crystallite size Branched C_(10)isomers

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Recent advances in electrochemical synthesis of urea via C-N coupling

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Journal of Energy Chemistry 2024年第11期98卷 294-310页

作者： Chen Wang Wenqi Gao Wei Hu Wei Wen Shengfu Wang Xiuhua Zhang Dafeng Yan Bao Yu Xia Hubei Key Laboratory for Precision Synthesis of Small Molecule Pharmaceuticals&Ministry of Education Key Laboratory for the Synthesis and Application of Organic Functional Molecules&College of Chemistry and Chemical Engineering Hubei UniversityWuhan 430062HubeiChina School of Chemistry and Chemical Engineering State Key Laboratory of Materials Processing and Die&Mould TechnologyKey Laboratory of Material Chemistry for Energy Conversion and Storage(Ministry of Education)Hubei Key Laboratory of Material Chemistry and Service FailureWuhan National Laboratory for OptoelectronicsHuazhong University of Science and Technology(HUST)Wuhan 430074HubeiChina

Urea is widely used as fertilizer and is a key substance supporting global food production. However, the traditional industrial synthesis of urea faces the challenges with high energy consumption and serious environmental problems. With the increasing global demand for environmental protection and sustainable development, it is much necessary to develop novel and clean methods for the synthesis of *** provides an efficient and renewable synthesis route that can directly produce urea at room temperature and atmospheric pressure by the coupling of CO_(2) and nitrogenous molecules. In this review, we summarized the most recent advances in electrochemical synthesis of urea via CAN coupling systematically, focusing on the coupling of CO_(2) and different nitrogen sources. And the associated coupling mechanism, catalysts optimization, and electrolyzer design are well discussed. Moreover, the challenges and future directions for electrocatalytic CAN coupling are prospected. This review will provide timely and valuable guidance for others and attract more interests to promote the development of electrochemical synthesis of urea or other valuable chemicals containing CAN bond.

关键词： Electrocatalysis CAN coupling Urea synthesis CO_(2)and N_(2)fixation

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Cu-Cu low-temperature diffusion bonding by spark plasma sintering:Void closure mechanism and mechanical properties

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Journal of materials Science & technology 2023年第8期139卷 210-223页

作者： Wendi Li Yuxin Liang Yang Bai Tiesong Lin Bangsheng Li Jicai Feng School of Materials Science and Engineering Harbin Institute of TechnologyHarbin 150001China State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001China National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of TechnologyHarbin 150001China

In this study,combining the single point diamond turning(SPDT)and spark plasma sintering(SPS),we achieved high-strength diffusion bonding of copper at an ultra-low temperature of 202℃(0.35 T_(m),T_(m):absolute temperature of the melting point).Additionally,the closure mechanism of interfacial micro-and nano-voids during the Cu-Cu SPS diffusion bonding is systematically revealed for the first *** micro-voids,the pulsed current is found to induce additional diffusion flux and plastic deformation,thereby facilitating the void *** dynamics(MD)simulation revealed that at the atomic scale,high-energy Cu atoms induced by the pulsed current can significantly promote the diffusion of low-energy atoms in their vicinity and accelerate the void *** study also proposes a novel“evaporation-deposition”nano-void closure mechanism for the previously unstudied nano-void closure *** results show that the synergistic effect of the pulsed current and nanoscale surface rough-ness can significantly improve joint *** a low temperature of 405℃(0.5 T_(m)),on combining the computerized numerical control(CNC)turning and SPS diffusion bonding,the joint strength can reach 212 MPa,while that for the joint obtained by traditional hot pressing diffusion bonding at the same tem-perature is only 47 *** obtained an ultra-high joint strength of 271 MPa using the combined process of SPDT and SPS diffusion bonding at an ultra-low temperature of 202℃(0.35 T_(m)),which is approximately 600℃ lower than the traditional diffusion bonding process temperature of 800℃(0.79 T_(m)).To sum up,this study provides a novel method and theoretical support for realizing low-temperature high-strength diffusion bonding.

关键词： Spark plasma sintering Diffusion bonding Void closure mechanism Mechanical property Molecular dynamics

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Phase transition of multi-component(TiZrVNb)C ceramics—Part I:Phase decomposition induced by carbon content

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Journal of advanced Ceramics 2024年第5期13卷 679-688页

作者： Qingyi Kong Rao Zhang Lei Chen Sijia Huo Wenyu Lu Yujin Wang Boxin Wei Yu Zhou Institute for Advanced Ceramics School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150080China Key Laboratory of Advanced Structure‒Function Integrated Materials and Green Manufacturing Technology Harbin Institute of TechnologyHarbin 150001China School of Materials Science and Chemical Engineering Harbin University of Science and TechnologyHarbin 150001China National Key Laboratory of Precision Hot Processing of Metals Harbin Institute of TechnologyHarbin 150001China

Phase decomposition can effectively enhance the mechanical properties of carbide ceramics and can overcome the difficulty of enhancing the mechanical properties of single-phase multicomponent carbide *** this work,a series of nonstoichiometric(TiZrVNb)Cx ceramics were prepared by spark plasma sintering(SPS)at different *** effects of the carbon content on the phase composition,microstructure evolution,and mechanical properties were investigated in *** decomposition occurred with decreasing carbon *** different solid solutions of(Ti,V)-rich and Zr-rich phases formed from the decomposition of equimolar single-phase solid solutions,namely,the Zr-poor phase and Zr-rich phase,*** distribution of Nb element is relatively *** semicoherent interfaces between the Zr-poor phase and the Zr-rich phase can harden and strengthen effectively under the synergistic effect of grain *** with phase decomposition structures have apparent advantages compared to single-phase high-entropy *** work provides an important train of thought for the microstructure tailoring and properties optimization of multi-component carbide ceramics.

关键词： multicomponent ceramics nontoichiometry microstructure evolution phase decomposition mechanical properties

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Microstructure evolution and shape memory behaviors of Ni_(47)Ti_(44)Nb_(9)alloy subjected to multistep thermomechanical loading with different prestrain levels

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Journal of materials Science & technology 2024年第4期171卷 80-93页

作者： Y.H.Zhang H.Li Z.W.Yang X.Liu Q.F.Gu State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Shaanxi Key Laboratory of High-Performance Precision Forming Technology and Equipment Northwestern Polytechnical UniversityXi’an 710072China

Ni_(47)Ti_(44)Nb_(9)shape memory alloy(SMA)is a promising material in the aerospace field due to its wide transformation *** application of shape memory effect depends on multistep thermomechan-ical loading,viz.,low-temperature deformation and subsequent heating to ***-temperature deformation prestrain plays a pivotal role in shape memory properties tailoring of SMA ***,microstructure evolution and deformation mechanisms of Ni_(47)Ti_(44)Nb_(9)SMA subjected to vari-ous prestrain levels are still *** this end,microstructure evolution and shape memory behaviors of Ni_(47)Ti_(44)Nb_(9)alloy subjected to multistep thermomechanical loading with prestrain levels of 8%-16%at-28℃(M_(s)+30℃)were *** results demonstrate that the stress-strain curve of the specimen exhibits four distinct stages at a maximal prestrain of 16%.Whereas stageⅡand stageⅢend at prestrains of∼8%and∼12%,*** stageⅡ,the stress-induced martensitic transformation is accompanied by the dislocation slip of the NiTi matrix andβ-Nb *** stageⅢ,in addition to the higher density of dislocations and further growth of stress-induced martensite variants(SIMVs),(001)compound twins are introduced as a result of the(001)deformation twinning in stress-induced ***{20-1}martensite twins are gradually introduced in stageⅣ.Correspondingly,after subsequent unloading and heating,a higher density of{114}austenite twins form in the specimen with a larger prestrain of 16%.With increasing prestrain from 8%to 16%,the recoverable strainε_(re)^(T)upon heating increases first and then ***ε_(re)^(T)obtains a maximum of 7.03%at 10%prestrain and de-creases to 6.17%at 16%*** increase ofε_(re)^(T)can be attributed to the formation of new SIMVs,the further growth of existing SIMVs,and the recoverable(001)compound *** the decrease ofε_(re)^(T)is mainly associated with the irrecoverable strain by{20−1}martensite *** effe

关键词： Ni_(47)Ti_(44)Nb_(9)shape memory alloy Wide transformation hysteresis Thermomechanical loading Microstructure evolution Shape memory behaviors Stress-induced martensitic transformation Deformation twinning

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Enabling a stable and dendrite-suppressed Zn anode via facile surface roughness engineering

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Journal of materials Science & technology 2022年第7期102卷 272-277页

作者： Jinghao Li Kehan Le Wei Wei State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China International School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China

The safety and cycle lifespan of zinc metal-based aqueous batteries are greatly restricted by zinc *** poor cycling performance of zinc metal anode is often considered to be impacted by the dendrite growth,surface passivation,zinc metal corrosion and hydrogen evolution reaction,while surface roughness is a matter that has often been ignored in past ***,a roughness gradient is constructed on the zinc anode surface by a simple grinding and pasting *** has been found the modified zinc anodes with lower surface roughness exhibit the smaller zinc deposition overpotential and longer cycle ***,in situ optical microscopy photographs indicate that the zinc anode with an optimized roughness enables more uniform distribution of zinc precipitation and corrosion sites,which will facilitate a stable cycling performance of aqueous zinc ion *** Zn anode dendrite-suppressing mechanism via surface roughness engineering was revealed through finite element computational *** results emphasize the effectiveness of roughness engineering for tuning the surface physics of Zn anode and provide a facile strategy to develop better and safer aqueous zinc ion batteries.

关键词： Surface roughness Zn metal anode Surface engineering Aqueous zinc-ion batteries

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Vertically mounting molybdenum disulfide nanosheets on dimolybdenum carbide nanomeshes enables efficient hydrogen evolution

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Nano Research 2022年第5期15卷 3946-3951页

作者： Tingting Wang Pengyan Wang Yajun Pang Yitian Wu Jin Yang Hao Chen Xiaorui Gao Shichun Mu Zongkui Kou State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China College of Chemistry and Materials Engineering Zhejiang A&F UniversityHangzhou 311300China Jiangsu Laboratory of Advanced Functional Materials School of Electronic and Information EngineeringChangshu Institute of TechnologyChangshu 215500China

Designing hierarchical heterostructure to optimize the adsorption of hydrogen intermediate(H*)is impressive for hydrogen evolution reaction(HER)***,we show that vertically mounting two-dimensional(2D)layered molybdenum disulfide(MoS_(2))nanosheets on 2D nonlayered dimolybdenum carbide(Mo_(2)C)nanomeshes to form a hierarchical heterostructure largely accelerates the HER kinetics in acidic electrolyte due to the weakening adsorption strength of H*on 2D Mo_(2)C *** hierarchical MoS2/Mo2C heterostructure therefore gives a decrease of overpotential for up to 500 mV at-10 mA·cm^(-2)and an almost 200-fold higher kinetics current density compared with the pristine Mo2C nanomeshes and maintains robust stability with a small drop of overpotential for only 16 mV upon 5,000 *** further rationalize this finding by theoretical calculations and find an optimized adsorption free energy of H*,identifying that the MoS_(2)featuring strong H*desorption plays a key role in weakening the strong binding of Mo_(2)C with H*and therefore improves the intrinsic HER activity on active C sites of Mo_(2)*** present finding shines the light on the rational design of heterostructured catalysts with synergistic geometry.

关键词： hydrogen evolution reaction transition metal carbide transition metal disulfide two-dimensional nonlayered/layered heterostructure hydrogen adsorption/desorption

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Direct conversion of CO_(2)to graphene via vapor–liquid reaction for magnesium matrix composites with structural and functional properties

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Journal of Magnesium and Alloys 2023年第4期11卷 1206-1212页

作者： Xuejian Li Xiaojun Wang Xiaoshi Hu Chao Xu Wenzhu Shao Kun Wu State Key Laboratory of Advanced Welding and Joining Harbin Institute of TechnologyHarbin 150001PR China National Key Laboratory of Precision Hot Processing of Metal Harbin Institute of TechnologyHarbin 150001PR China

Converting CO_(2)to valuable materials is attractive in environmental protection and resource *** this study,a vapor-liquid interface reaction system for mass production of high-quality graphene is *** graphene obtained has high crystallinity and few defects during the reaction of CO_(2)and Mg *** growth mechanism of graphene is demonstrated in vapor-liquid interface area by combining the CO_(2)bubbles as a soft template to guide growth with the confinement effect of dense MgO *** quality of the graphene is verified by epoxy composites with high electromagnetic shielding ***,the V-L reaction method ingeniously solves the dispersion of graphene in metal,providing a preparation strategy of Mg matrix composites with structure and function integration.

关键词： Graphene Vapor-liquid interface Magnesiothermic reaction Dispersion Shielding effectiveness

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Interfacial engineering of holey platinum nanotubes for formic acid electrooxidation boosted water splitting

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Journal of Energy Chemistry 2023年第2期77卷 209-216,I0006页

作者： Zi-Xin Ge Yu Ding Tian-Jiao Wang Feng Shi Pu-Jun Jin Pei Chen Bin He Shi-Bin Yin Yu Chen Key Laboratory of Macromolecular Science of Shaanxi Province Key Laboratory of Applied Surface and Colloid Chemistry(Ministry of Education)Shaanxi Key Laboratory for Advanced Energy DevicesShaanxi Engineering Lab for Advanced Energy TechnologySchool of Materials Science and EngineeringShaanxi Normal UniversityXi’an 710062ShaanxiChina College of New Materials and New Energies Shenzhen Technology UniversityShenzhen 518118GuangdongChina MOE Key Laboratory of New Processing Technology for Non-ferrous Metals and Materials Guangxi Key Laboratory of Processing for Non-ferrous Metals and Featured MaterialsGuangxi UniversityNanning 530004GuangxiChina

Both structure and interface engineering are highly effective strategies for enhancing the catalytic activity and selectivity of precious metal *** this work,we develop a facile pyrolysis strategy to synthesize the high-quality holey platinum nanotubes(Pt-H-NTs)using nanorods-like Pt^(Ⅱ)-phenanthroline(PT)coordination compound as self-template and self-reduction ***,an up-bottom strategy is used to further synthesize polyallylamine(PA)modified Pt-H-NTs(Pt-HNTs@PA).PA modification sharply promotes the catalytic activity of Pt-H-NTs for the formic acid electrooxidation reaction(FAEOR)by the direct reaction ***,PA modification also elevates the catalytic activity of Pt-H-NTs for the hydrogen evolution reaction(HER)by the proton enrichment at electrolyte/electrode *** from the high catalytic activity of Pt-H-NTs@PA for both FAEOR and HER,a two-electrode FAEOR boosted water electrolysis system is fabricated by using Pt-H-NTs@PA as bifunctio nal *** FAEOR boosted water electrolysis system only requires the operational voltage of 0.47 V to achieve the high-purity hydrogen production,showing an energy-saving hydrogen production strategy compared to traditional water electrolysis system.

关键词： Holey platinum nanotubes Chemical functionalization Formic acid oxidation reaction Hydrogen evolution reaction Water splitting

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