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Design and synthesis of a multifunctional g-C3N4@MOF for enhanced CO2 cycloaddition: Synergistic effects of Lewis acid-base sites and ionic liquid functionalization

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JOURNAL OF ORGANOMETALLIC CHEMISTRY 2025年 1026卷

作者： Zhao, Guofeng Qin, Peng Zhang, Chao Wang, Chao Zhang, Delu Zhuang, Tao Lv, Zhiguo Qingdao Univ Sci & Technol Coll Chem Engn State Key Lab Base Ecochem Engn Key Lab Multiphase Flow React & Separat Engn Shand Qingdao 266042 Peoples R China Wuhan Univ Technol State Key Lab Adv Technol Mat Synth & Proc Wuhan 430070 Peoples R China Qingdao Univ Sci & Technol Key Lab Rubber Plast Shandong Prov Key Lab Rubber & Plast Minist Educ Qingdao 266042 Peoples R China

The cycloaddition reaction of CO2 to synthesize cyclic carbonates is highly valuable for greenhouse gas resource utilization. In this study, a multifunctional g-C3N4@MOFs layered catalyst (BCN-MIL-IMNH2), containing Lewis acid-base sites and hydrogen bond donors (HBD), was prepared using a mild in-situ growth and covalent bonding strategy. At optimal performance conditions (120 degrees C, 1.5 MPa, 90 mg catalyst, 4 h), the BCN-MIL-IMNH2-2 catalyst exhibited excellent catalytic performance (YPC = 96.5 %, SPC = 99.0 %). The remarkable catalytic efficiency resulted from the combined effect of Lewis acid (B/Cr), Lewis base (Br-), and hydrogen bond donors (-NH2) active groups. The introduced Cr and B were effective in activating and opening (via nucleophilic attack by Br-) epoxides. Besides, the -NH2 group, serving as a hydrogen bond donor basic functional group, adsorbed and activated CO2 to form an intermediate carbamate. The enhanced stability was attributed to the covalent bonding strategy, which effectively immobilizes the amino functionalized ionic liquids within the MOFs of the composite material, thereby enhancing structural stability and preventing dissociation during the reaction process. After five cycles, the catalyst maintained excellent performance with a yield of approximately 93 %.

关键词： CO 2 cycloaddition Multifunctional Hydrogen bond donors Lewis acid-base Ionic liquids

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Nanohybrid of h-BN nanosheets supporting CeO2 enhanced epoxy composite coatings with excellent self-lubricating performance

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POLYMER COMPOSITES 2023年第10期44卷 6440-6453页

作者： Yang, Bi Chen, Beibei Dong, Wenquan Tong, Yang Li, Jiaye Jiangsu Univ Inst Adv Mat Sch Mat Sci & Engn Zhenjiang Peoples R China Henan Univ Sci & Technol Natl United Engn Lab Adv Bearing Tribol Luoyang Peoples R China Tsinghua Univ Dept Mech Engn State Key Lab Tribol Adv Equipment Beijing Peoples R China Chongqing Univ Technol Minist Educ Key Lab Adv Manufacture Technol Automobile Parts Chongqing Peoples R China Jiangsu Univ Sch Mat Sci & Engn Inst Adv Mat Zhenjiang 212013 Peoples R China

Polymer self-lubricating composite coatings have been widely used on the surface of machinery to extend the life of the moving systems/parts by controlling friction and wear. In this work, epoxy nanocomposite coating with the thickness of about 60 mu m was fabricated with addition of hexagonal boron nitride nanosheets (BNNSs)/CeO2 nanohybrid for enhancement in antifriction and wear resistance. The active BNNSs were first obtained by exfoliating h-BN with alkaline solution, and then the rare earth oxide of CeO2 nanoparticles were immobilized on the surface of BNNSs through hydrothermal method. The microstructure morphology and chemical composition of as-proposed BNNSs/CeO2 were characterized by field emission scanning electron microscopy, HRTEM, Fourier transform infrared spectroscopy, RS, X-ray diffraction, and X-ray photoelectron spectroscopy. And the tribological behaviors of epoxy nanocomposite coatings containing BNNSs, CeO2, and BNNSs/CeO2 were investigated comparatively using ball-on disc friction tester (MPX-3). And the 440C stainless-steel ball with diameter of 8 mm was used as the counterface material. Tribological tests showed that epoxy-BNNSs/CeO2 had the best friction and wear reduction properties, and the lowest coefficient of friction and wear rate of epoxy-based composite coating were achieved when the content of BNNSs/CeO2 was 0.5 wt%, with 84.9% and 96.3% reduction, respectively. Moreover, the effect of sliding conditions on the tribological performance of epoxy-BNNSs/CeO2 was investigated. The corresponding enhancing mechanisms of BNNSs/CeO2 were discussed as well.

关键词： CeO2 nanoparticles h-BN nanosheets microstructure nanocomposite coating self-lubrication

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Anchoring Pt single atoms on 3D flower-like NiMoP via Pt-Ni bonding with enhanced hydrogen evolution reaction

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JOURNAL OF COLLOID AND INTERFACE SCIENCE 2025年 688卷 233-240页

作者： Zhao, Gaoqiang Wang, Haipeng Zhang, Delu Si, Zhixiao Zhuang, Tao Lv, Zhiguo Zhang, Chao Qingdao Univ Sci & Technol Sch Chem Engn Qingdao 266042 Peoples R China Southern Univ Sci & Technol Dept Biomed Engn Guangdong Prov Key Lab Adv Biomat Shenzhen 518055 Peoples R China Qingdao Univ Sci & Technol Shandong Prov Key Lab Rubber Plast Minist Educ Qingdao 266042 Peoples R China

Introducing Pt single atoms (PtSA) into bimetallic phosphides to enhance their performance at higher current densities remains a significant challenge under alkaline conditions. We successfully anchored PtSA on 3D flowerlike NiMoP through a Pt-Ni bonding method. The 3D flower-like catalyst (PtSA@NiMoP) exhibits remarkably low overpotentials, requiring only 35 mV to achieve 10 mA cm- 2 and 66 mV at 100 mA cm- 2. Moreover, PtSA@NiMoP demonstrates a Tafel slope of 29.1 mV dec- 1 and maintains stability for 50 h at different current densities in 1.0 M KOH solution. After the introduction of PtSA, the average Ni-Ni bond length increases to 2.525 & Aring;, accompanied by a significant decrease in the Ni-Ni coordination number, indicating the successful formation of Pt-Ni bonds. Density functional theory (DFT) calculations reveal that PtSA accelerates water dissociation on the NiMoP surface and facilitates electron transfer from Ni to P, enhancing H+ reduction and promoting the Volmer step. Additionally, the hydrogen adsorption Gibbs free energy (Delta GH*) of PtSA@NiMoP is only -0.065 eV (close to 0 eV), which is favorable for H2 evolution. Meanwhile, the Pt serves as an active site that further accelerates H2 generation, synergistically improving the catalytic kinetics of the alkaline hydrogen evolution reaction (HER).

关键词： Electrocatalysis Hydrogen evolution Pt single atoms NiMoP Synergistic effects

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Could the Rebound Characteristics of Oblique Impact for SiO2 Particles Represent the Ash Particles?

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ACS OMEGA 2024年第9期9卷 10459-10467页

作者： Li, Xue Xie, Jun Dong, Ming Chen, Sheng Dong, Wenjie Wuhan Inst Technol Sch Opt Informat & Energy Engn Wuhan 430205 Peoples R China Dalian Univ Technol Sch Energy & Power Engn Key Lab Ocean Energy Utilizat & Energy Conservat Minist Educ Dalian 116024 Peoples R China Huazhong Univ Sci & Technol Sch Energy & Power Engn State Key Lab Coal Combust Wuhan 430074 Peoples R China Shenyang Aerosp Univ Coll Energy & Environm Shenyang 110136 Peoples R China

Collisions between particles or with a surface have been widely applied, in which the restitution coefficients are the important parameter to describe the particle rebound behavior. SiO2 particles are often used instead of ash particles in theoretical analyses;however, whether this is justifiable has not been confirmed. This paper compares the rebound characteristics of oblique impact for SiO2 particles and ash particles by experimental and theoretical analyses. Based on the rigid-body theory, the tangential restitution coefficients, rebound angle-particle center, and reflection angle-contact path predicted by SiO2 particles are basically in agreement with the experimental results for ash particles, especially at large impact angles. However, there is a slight error at 2.2 m/s as the velocity approaches the critical capture velocity.

关键词： Collisions Deposition Friction Particles Reaction products

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Experimental Study on Compression Failure of Type II Ballastless Track Slab Based on Optical Fiber Sensing

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TRANSPORTATION RESEARCH RECORD 2024年第10期2678卷 1594-1609页

作者： Zhang, Xuebing Quan, Yang Zheng, Zhizhou Wang, Li Cui, Hongtian Xie, Xiaonan Wu, Han Liu, Xiaochun Yang, Delei Wang, Huaping Xiang, Ping Xiangtan Univ Coll Civil Engn Xiangtan Hunan Peoples R China Cent South Univ Sch Civil Engn Changsha Hunan Peoples R China Huanghuai Univ Architecture Engn Coll Zhumadian Henan Peoples R China Lanzhou Univ Coll Civil Engn & Mech Lanzhou Peoples R China City Univ Hong Kong Dept Architecture & Civil Engn Hong Kong Peoples R China

Ballastless track structures are widely employed in high-speed rail networks because of their superior safety and durability. Among the various types of ballastless track, the Type II slab is currently one of the most extensively used and mature technologies in practice. Over the course of its service life, the damage within the ballastless track structure gradually accumulates in response to increased external loads. Therefore, it is crucial to continuously monitor the health condition of the track structure. In this study, a quasi-distributed fiber optic sensing system is adopted to monitor the deformation capacity and force performance of a Type II ballastless track slab under vertical load. The investigation aims to analyze the damage mechanism of the track structure under vertical pressure by assessing the deformation differences among its different components. The findings reveal that the incorporation of vertical reinforcement can enhance the pressure bearing capacity of the cement asphalt mortar layer to a certain extent, subsequently affecting the stress dilation. The stress performance of the ballastless track slab can be effectively monitored using the quasi-distributed fiber optic sensing technology under pressure. The outcomes of this research offer valuable insights for controlling displacement and analyzing damage in ballastless railway systems subjected to compression.

关键词： fiber optic sensing monitoring ballastless track type II slab compressive damage

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Study on performance enhancement driven by strain-induced α′ martensite transformation in a metastable dual-phase titanium alloy

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JOURNAL OF MATERIALS RESEARCH AND technology-JMR&T 2024年 30卷 7065-7075页

作者： Ji, Pengfei Xia, Chaoqun Liu, Shuguang Chen, Bohan Li, Bo Zhang, Han Tang, Huaguo Qiao, Zhuhui Shandong Lab Adv Mat & Green Manufacture Yantai Yantai 264006 Peoples R China Chinese Acad Sci Lanzhou Inst Chem Phys State Key Lab Solid Lubricat Lanzhou 730000 Peoples R China Yanshan Univ State Key Lab Metastable Mat Sci & Technol Qinhuangdao 066004 Peoples R China Hebei Univ Technol Sch Mat Sci & Engn Tianjin Key Lab Mat Laminating Fabricat & Interfa Tianjin 300130 Peoples R China Beijing Res Inst Automat Machinery Ind Co Ltd Engn Res Ctr Electrophys Apparat & Applicat Techn Beijing 100120 Peoples R China Henan Univ Sci & Technol Natl United Engn Lab Adv Bearing Tribol Luoyang 471023 Peoples R China

This study improves ductility while maintaining the ultimate tensile strength (UTS) of a Ti-30Zr-5Al-3V alloy without changing chemical composition via microstructural control of the double-phase (alpha+beta). +beta). The deformation mechanism of the alloy is controlled by regulating the volume fraction of the beta phase, resulting in an ultra-high strain hardening capacity that enhances the material's mechanical properties. The water-quenched specimen exhibits an ultra-high strain hardening capacity attributed to the increase in both back and effective stresses as the deformation proceeds. Heterostructure deformation and the accumulation of geometrically necessary dislocations (GNDs) near grain boundaries induce back-stress strengthening. Effective stress strengthening primarily arises from dislocation reinforcement, including the dynamic Hall-Petch effect caused by strain-induced alpha ' martensite transformation (SIMT) and the hindering effect of GNDs migration. The reorientation and merging of alpha grains are inconducive to high strain hardenability. However, a lower beta phase volume fraction in the air-cooled specimen results in less SIMT, and even small strains could lead to significant grain coarsening. High strain hardening rates could not be maintained solely through back stress strengthening, leading to premature material failure. In comparison to the air-cooled specimen, the water-quenched specimen demonstrates a significantly increased ultra-high strain hardening capability, resulting in enhanced uniform elongation (from similar to 3.4 to similar to 9.6%) and overall elongation (from similar to 6.2 to similar to 13.3%) without reducing the UTS.

关键词： Titanium alloys Mechanical properties Deformation mechanisms Transformation-induced plasticity

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Studies of beam ion confinement to enhance plasma performance on EAST

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Plasma Science and technology 2024年第12期26卷 18-30页

作者： Jing FU Juan HUANG Jinfang WANG Limin YU Cheonho BAE Jiafeng CHANG Kaiyang HE Yueheng HUANG Pan LI Wei GAO Yifei JIN Tianqi JIA Minrui WANG Yanxu SUN Chang SHI Shusong WANG Xihui WANG Hailin ZHAO Yifeng ZHENG Yahong XIE Guoqiang ZHONG Qing ZANG Haiqing LIU Jinping QIAN Hefei Institutes of Physical Science Chinese Academy of SciencesHefei 230031People’s Republic of China University of Science and Technology of China Hefei 230026People’s Republic of China Department of Physics East China University of Science and TechnologyShanghai 200237People’s Republic of China Anhui University Hefei 230601People’s Republic of China

A key physics issue for achieving steady-state high-performance plasmas on EAST tokamak is to decrease beam-ion losses to improve plasma confinement during neutral beam injections(NBIs).To decrease the beam losses,previous counter-I_(p)NBI injections are upgraded to co-I_(p)*** shows that due to the reversed direction of drift across the flux surfaces caused by the pitch angle,the beam prompt loss fraction decreases from about 49%to 3%after the ***,because of the change of entire beam path,beam shine-through(ST)loss fraction for counter-I_(p)tangential and counter-I_(p)perpendicular injections is reversed to co-I_(p)tangential and co-I_(p)perpendicular injections,*** to the change in the initial trapped-confined beam ion fraction caused by the peaked pitch profiles,the losses induced by toroidal ripple field are also reversed after the *** further improve the beam-ion confinement under the present NBI layout,the amplitudes of toroidal field are increased from 1.75 to 2.20 *** shows that,due to the smaller orbit width and peaked pitch angle profile,the beam prompt loss power is lower with higher toroidal *** to the synergy of higher initial trapped-confined beam ion fraction and narrower Goldston-White-Boozer(GWB)boundary,the loss induced by ripple diffusion is higher with higher toroidal *** combined effect of beam ST loss,prompt loss and ripple loss,contributes to the increase in beam ion *** decrease in beam loss power enhances beam heating efficiency,especially the fraction of beam heating ***,comparison between simulation and measurement by^(235)U fission chamber(FC)indicates that the increase in neutron rate is mainly contributed by improvement of beam-ion *** study can provide potential support for beam operation and high-T_(i)experiment on EAST tokamak.

关键词： beam-ion losses plasma performance neutral beam injections tokamak

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Efficiency Improvement of 6.78MHz Metamaterials for WPT System 26

Efficiency Improvement of 6.78MHz Metamaterials for WPT Syst...

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26th International Conference on Electrical Machines and Systems, ICEMS 2023

作者： Yan, Lihui Gao, Huiming Rong, Cancan Liao, Zhijuan Xia, Chenyang Wang, Qiong China University of Mining and Technology Xuzhou China

ISBN: (纸本)9798350317589

There are many applications for wireless power transfer (WPT), but as the transmission distance increases, the magnetic field energy decays and the transmission efficiency drops sharply. In this paper, a focused electromagnetic metamaterial (MM) unit is designed. When the operating frequency is 6.78 MHz, the permeability of the metamaterial unit is negative, and the purpose of focusing the magnetic field is achieved. The WPT system using a 3× 3 array metamaterial was established. Through simulation, the magnetic field diagram and transmission efficiency of WPT system with metamaterial slab varying different transmission distances are obtained. The magnetic field around the Rx coil is significantly improved after adding the MM slab. When the transmitting and receiving coils are 20cm apart, the transmission efficiency of the system is improved the most with 41.03%. © 2023 IEEE.

关键词： Metamaterials

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Scenario Generation of Renewable Energy Based on Improved Diffusion Model

Scenario Generation of Renewable Energy Based on Improved Di...

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2023 IEEE Sustainable Power and Energy Conference, iSPEC 2023

作者： Li, Sheng Xu, Chuanyu Wei, Lishen Li, Ruijie Ai, Xiaomeng State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

ISBN: (纸本)9798350322699

The large-scale integration of renewable energy into the power system has resulted in increased complexity of its uncertainty. This complexity arises from the rapidly increased renewable energy sites and the intricate spatial-temporal correlations involved. To offer a more precise description of the uncertainty of renewable energy, a scenario generation method based on an improved diffusion model is proposed. This approach can autonomously learn the probability distribution and spatiotemporal correlation of the training data. It utilizes a U-Net model to progressively denoise noise and iteratively generate renewable energy scenarios. Experiments using historical power data from five wind farms and five PV plants in Jiangsu Province show that the training process of the proposed method is more stable compared to existing methods. Moreover, the proposed method achieves higher accuracy in fitting probability distribution and captures the spatial correlation between multiple sites more accurately. © 2023 IEEE.

关键词： diffusion Model renewable energy scenario generation unsupervised learning

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Low-Cost Halide Electrolytes Li2+x Hf1-x Fex Cl6 with Superior Ionic Conductivities for All-Solid-state Lithium-Metal Based Batteries

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ACS SUSTAINABLE CHEMISTRY & engineering 2024年第18期12卷 7012-7025页

作者： Tuo, Kaiyong Yin, Fusheng Sun, Chunwen China Univ Min & Technol Beijing Sch Chem & Environm Engn Beijing 100083 Peoples R China

All-solid-state batteries (ASSBs) employing inorganic solid electrolytes have been considered as promising candidates for next generation energy storage owing to their intrinsic safety performance and high energy density. Designing highly ionically conductive and (electro)chemically stable inorganic solid electrolytes utilizing cost-effective materials is of vital importance for the development of practical ASSBs. Herein, we report a series of new lithium-conducting superionic halides Li2+xHf1-xFexCl6 that are free of rare-earth elements with high ionic conductivities up to 0.91 mS cm(-1) at 30 degrees C by aliovalent substitution with low-cost and earth-abundant Fe elements. By means of complementary characterization techniques and bond-valence site energy (BVSE) calculations, we gain insights into the influence of aliovalent doping engineering on the local structural environment and the underlying lithium-ion transport properties of Fe3+-substituted Li2HfCl6. Importantly, it is demonstrated that the prevalently existent distortion of octahedral structure and redistribution of the lithium ion induced by the aliovalent substitution strongly benefits the transport properties. Notably, the formation of infinitely 3D connected lithium-ion migration pathways comprised of a directly connected face-sharing octahedron along the c direction is revealed by structural analysis and theoretical calculations. Additionally, owing to the intrinsic oxidation tolerance of Fe3+-substituted Li2HfCl6, the fabricated bulk-type ASSBs with uncoated LiCoO2 deliver an outstanding electrochemical performance.

关键词： halide electrolytes ionic conductivity aliovalentdoping mechanochemical milling all-solid-statebatteries

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