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富氮碳鞘内阶梯层状Mo_(2)C异质结用于高效CO_(2)化学固定

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Chinese Journal of Catalysis 2024年第3期58卷 138-145页

作者：许玉帅汪红辉李奇远张仕楠夏思源许冬类伟巍陈接胜李新昊上海交通大学化学化工学院变革性分子前沿科学中心上海200240 上海化工研究院有限公司上海200062 迪肯大学前沿材料研究所澳大利亚吉朗维多利亚

在多相催化体系中,开发具有高催化活性的多相催化剂是实现小分子绿色转化的核心.过渡金属碳化物,特别是碳化钼(Mo_(2)C),因其活性与贵金属相当且成本低廉,在小分子转化方面具有应用潜力.二维(2D)过渡金属碳化物因其平面结构两侧具有可... 详细信息

在多相催化体系中,开发具有高催化活性的多相催化剂是实现小分子绿色转化的核心.过渡金属碳化物,特别是碳化钼(Mo_(2)C),因其活性与贵金属相当且成本低廉,在小分子转化方面具有应用潜力.二维(2D)过渡金属碳化物因其平面结构两侧具有可暴露的活性位点,在小分子转化和能量储存方面受到越来越多的关注.然而,在催化剂或电极材料的批量制备过程中,二维层的堆积会导致表面活性位点损失,严重影响其性能.此外,层状材料的堆积还可能阻碍有机分子的有效传递,形成传质屏障,进一步影响催化过程.特别是,二维过渡金属碳化物表面的氧化会导致活性位点的大量损失,这已成为当前亟待解决的关键问题.因此,开发一种能确保层状Mo_(2)C材料的机械和化学稳定性的有效合成方法,对于推动其实际应用至关重要.本文利用可控氧扩散蚀刻法合成了一种富氮碳鞘包覆的“阶梯状”2D-Mo_(2)C异质结材料(2D-Mo_(2)C@NC).该材料因具有独特的阶梯层状结构和整流界面,可以显著促进CO_(2)与邻苯二胺的羰基化反应,并对CO_(2)与多种二胺衍生物的羰基化反应均表现出较好的催化活性.通过密度泛函理论计算和紫外光电子能谱分析发现,Mo_(2)C与NC壳层的接触界面形成了整流接触,导致电子从NC壳层流向Mo_(2)C,进而形成富电子的层状Mo_(2)C.随着NC壳层氮含量的增加,Mo_(2)C的电子富集程度逐渐增加.进一步的理论计算和CO_(2)程序升温脱附实验表明,CO_(2)吸附依赖于2D-Mo_(2)C的电子富集程度,并随2D-Mo_(2)C的电子富集程度增加而增强.这种电子富集特性使得2D-Mo_(2)C表面能够活化CO_(2)分子,形成高度扭曲的预吸附结构(键角为118.8°),有利于后续与二胺的羰基化反应.邻苯二胺与CO_(2)羰基化反应的吉布斯自由能计算结果表明,电子的富集程度对反应决速步的能垒影响较小.因此,推测CO_(2)分子在富电子Mo_(2)C表面的预吸附增强是促进CO_(2)羰基化反应的直接因素.实验结果也表明,2D-Mo_(2)C@NC催化剂催化邻苯二胺与CO_(2)羰基化反应的催化活性随2D-Mo_(2)C的电子密度增强而提高.优化后的阶梯状异质结2D-Mo_(2)C@NC样品的CO_(2)吸附量高于核壳状异质结Mo_(2)C@NC样品,且催化性能和CO_(2)吸附量存在明显的正相关关系,证实了阶梯状异质结结构所暴露出的更多富电子Mo_(2)C活性位点可以促进CO_(2)的预吸附及随后的活化过程.此外,X射线光电子能谱结果表明,富电子的2D-Mo_(2)C表现出优于Mo_(2)C的化学稳定性,不易被氧化.在优化条件下制得的2D-Mo_(2)C@NC催化剂表现出了最佳催化性能,在较低的反应温度下,其催化邻苯二胺与CO_(2)羰基化反应生成2-苯并咪唑啉酮的TOF值为6.1‒10.2 h^(‒1),比文献报道的最佳结果高4.2倍.综上,本文成功地开发了一种有效的可控氧扩散蚀刻策略,合成出具有高机械和化学稳定性的“阶梯状”2D-Mo_(2)C异质结材料,并用于高效催化CO_(2)和邻苯二胺羰基化生成2-苯并咪唑啉酮.该可控氧扩散蚀刻方法可以扩展到其他二维碳化物的制备,并进一步扩展其在光催化和电催化系统中的应用,为二维异质结材料的合成和应用提供了参考和新思路.

关键词：电子富集2D-Mo_(2)C CO_(2)固定肖特基异质结羰基化非均相催化

Tunable hydrogen coverage on electron-deficient platinum nanoparticles for efficient hydrogenation reactions

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Nano Research 2023年第7期16卷 8751-8756页

作者： Lu-Han Sun Qi-yuan Li Yu-Shuai Xu si-yuan xia Dong Xu Xiu Lin Jingsan Xu Jie-Sheng Chen Guo-Dong Li Xin-Hao Li School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative MoleculesShanghai Jiao Tong UniversityShanghai 200240China School of Chemistry and Physics Faculty of ScienceCentre for Materials ScienceQueensland University of TechnologyBrisbaneQLD 4001Australia State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of ChemistryJilin UniversityChangchun 130012China

Dissociation of active H species over the catalytic sites with the carbon-supported Pt metals as the mainstream catalysts is crucial to facilitate hydrogen donation and accelerate the hydrogen addition process in catalytic hydrogenation systems to produce polymers,pharmaceuticals,agrochemicals,fragrances,and biofuels at million-ton *** attention has been paid to the design of the more active catalytic site to effectively adsorb and activate reactants and H_(2) *** the same time,there is still a huge room to develop powerful strategies to accelerate the donation of acted H species to the reactants from the Pt surface further to boost the final catalytic efficiencies of Pt catalysts and depress the total Pt ***,we present a new strategy for promoting the Pt-H bond dissociation by increasing surface hydrogen coverage on designed electron-deficient Pt *** electron deficiency of Pt nanoparticles has been successfully tuned by constructing a rectifying contact with an even“noble”boron-rich carbon support(Pt/BC).Theoretical and experimental results confirm the dominant role of the pronounced electron deficiencies of Pt nanoparticles in enhancing the H coverage for 2.3 times higher than that of neutral Pt nanoparticles,significantly boosting the Pt-H bond dissociation and thus the whole hydrogenation process as reflected by the extremely high turnover frequency(TOF)value of 388 h^(-1)at 30℃ and 10 bar H_(2) for phenol hydrogenation on the Pt/BC,outperforming the bench-marked catalysts by a factor of 9.

关键词： hydrogenation hydrogen coverage Schottky barrier heterogeneous catalysis

Numerical and theoretical study of large-scale failure of strata overlying sublevel caving mines with steeply dipping discontinuities

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International Journal of Minerals,Metallurgy and Materials 2024年第8期31卷 1799-1815页

作者： Kaizong xia Zhiwei si Congxin Chen xiaoshuang Li Junpeng Zou Jiahao yuan State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan 430071China University of Chinese Academy of Sciences Beijing 100049China School of Urban Construction Changzhou UniversityChangzhou 213164China Faculty of Engineering China University of Geosciences(Wuhan)Wuhan 430074China

The deformation and fracture evolution mechanisms of the strata overlying mines mined using sublevel caving were studied via numerical ***,an expression for the normal force acting on the side face of a steeply dipping superimposed cantilever beam in the surrounding rock was deduced based on limit equilibrium *** results show the following:(1)surface displacement above metal mines with steeply dipping discontinuities shows significant step characteristics,and(2)the behavior of the strata as they fail exhibits superimposition ***,failure first occurs in certain superimposed strata slightly far from the ***,with the constant downward excavation of the orebody,the superimposed strata become damaged both upwards away from and downwards toward the *** process continues until the deep part of the steeply dipping superimposed strata forms a large-scale deep fracture plane that connects with the *** deep fracture plane generally makes an angle of 12°-20°with the normal to the steeply dipping *** effect of the constant outward transfer of strata movement due to the constant outward failure of the superimposed strata in the metal mines with steeply dipping discontinuities causes the scope of the strata movement in these mines to be larger than *** strata in the metal mines with steeply dipping discontinuities mainly show flexural toppling ***,the steeply dipping structural strata near the goaf mainly exhibit shear slipping failure,in which case the mechanical model used to describe them can be simplified by treating them as steeply dipping superimposed cantilever *** taking the steeply dipping superimposed cantilever beam that first experiences failure as the key stratum,the failure scope of the strata(and criteria for the stability of metal mines with steeply dipping discontinuities mined using sublevel caving)can be obtained via iterative computations from the ke

关键词： sublevel caving mines universal distinct element code(UDEC)numerical approach large-scale ground movement steeply dipping superimposed cantilever beam toppling failure

Production induced fracture closure of deep shale gas well under thermo-hydro-mechanical conditions

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Petroleum Science 2024年第3期21卷 1796-1813页

作者： Shi-Ming Wei Yang xia Yan Jin Xu-Yang Guo Jing-Yu Zi Kai-Xuan Qiu si-yuan Chen College of Science China University of Petroleum(Beijing)Beijing102249China CNOOC Research Institute Ltd Beijing100028China The University of Hong Kong Hong Kong999077China

Deep shale gas reservoirs have geological characteristics of high temperature,high pressure,high stress,and inferior ability to pass through *** multi-stage fractured horizontal well is the key to exploiting the deep shale gas ***,during the production process,the effectiveness of the hydraulic fracture network decreases with the closure of fractures,which accelerates the decline of shale gas *** this paper,we addressed the problems of unclear fracture closure mechanisms and low accuracy of shale gas production prediction during deep shale gas *** we established the fluid—solid—heat coupled model coupling the deformation and fluid flow among the fracture surface,proppant and the shale *** the fluid—solid—heat coupled model was applied to the fracture network,it was well solved by our numerical method named discontinuous discrete fracture *** with the conventional discrete fracture method,the discontinuous discrete fracture method can describe the three-dimensional morphology of the fracture while considering the effect of the change of fracture surface permeation coefficient on the coupled fracture—matrix flow and describing the displacement discontinuity across the *** simulations revealed that the degree of fracture closure increases as the production time proceeds,and the degree of closure of the secondary fractures is higher than that of the primary *** creep and proppant embedment both increase the degree of fracture *** reduction in fracture surface permeability due to proppant embedment reduces the rate of fluid transfer between matrix and fracture,which has often been overlooked in the ***,it significantly impacts shale gas production,with calculations showing a 24.7%cumulative three-year yield *** study is helpful to understand the mechanism of hydraulic fracture ***,it provides the theoretical guidance for maintaining the long

关键词： Shalegas Fracture closure Fluid-solid-heat coupling Discontinuous discrete fracture

Study of baryon number transport dynamics and strangeness conservation effects using-hadron correlations

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Nuclear Science and Techniques 2024年第7期35卷 147-156页

作者： Wei-Jie Dong xiao-Zhou Yu si-yuan Ping xia-Tong Wu Gang Wang Huan-Zhong Huang Zi-Wei Lin Key Laboratory of Nuclear Physics and Ion-beam Application(MOE) Fudan UniversityShanghai 200433China Department of Physics and Astronomy University of CaliforniaLos AngelesCA 90095USA Department of Physics East Carolina UniversityGreenvilleNC 27858USA

In nuclear collisions at RHIC energies,an excess ofΩhyperons over n is observed,indicating that几has a net ba ryon number despites and 3 quarks being produced in *** ba ryon number inΩmay have been transported from the incident nuclei and/or produced in the baryon-pair production ofΩ with other types of anti-hyperons such *** investigate these two scenarios,we propose to measure the correlations betweenΩand K and betweenΩand *** use two versions,the default and string-melting,of a multiphase transport(AMPT)modelto illustrate the method for measuring the correlation and to demonstrate the general shape ofthe *** present the S 2-hadron correlations from simulated Au+Au collisions at√SNN=7.7 and 14.6 GeV and discuss the dependence on the cllision energy and on the hadronization scheme in these two AMPT *** correlations can be used to explore the mechanism of baryon number transport and the effects of baryon number and strangeness conservation on nuclear collisions.

关键词： Baryon number transport Strangeness conversation Correlation Gluon junction

Numerical simulations for radon migration and exhalation behavior during measuring radon exhalation rate with closed-loop method

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Nuclear Science and Techniques 2024年第1期35卷 81-95页

作者： Ming xia Yong-Jun Ye Shu-yuan Liu School of Resources Environment and Safety Engineering University of South ChinaHengyang 421001China Key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy University of South ChinaHengyang 421001China

Accurate measurements of the radon exhalation rate help identify and evaluate radon risk regions in the *** these measurement methods,the closed-loop method is frequently ***,traditional experiments are insufficient or cannot analyze the radon migration and exhalation patterns at the gas–solid interface in the accumulation *** CFD-based technique was applied to predict the radon concentration distribution in a limited space,allowing radon accumulation and exhalation inside the chamber intuitively and *** this study,three radon exhalation rates were defined,and two structural ventilation tubes were designed for the *** consistency of the simulated results with the variation in the radon exhalation rate in a previous experiment or analytical solution was *** effects of the vent tube structure and flow rate on the radon uniformity in the chamber;permeability,insertion depth,and flow rate on the radon exhalation rate and the effective diffusion coefficient on back-diffusion were *** on the results,increasing the inser-tion depth from 1 to 5 cm decreased the effective decay constant by 19.55%,whereas the curve-fitted radon exhalation rate decreased(lower than the initial value)as the deviation from the initial value increased by approximately 7%.Increasing the effective diffusion coefficient from 2.77×10^(-7) to 7.77×10^(-6) m^(2) s^(-1) made the deviation expand from 2.14 to 15.96%.The conclusion is that an increased insertion depth helps reduce leakage in the chamber,subject to notable back-diffusion,and that the closed-loop method is reasonably used for porous media with a low effective diffusion coefficient in view of the back-diffusion *** CFD-based simulation is expected to provide guidance for the optimization of the radon exhalation rate measurement method and,thus,the accurate measurement of the radon exhalation rate.

关键词： Radon exhalation Numerical simulation Accumulation chamber

Interleukins in Epilepsy:Friend or Foe

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Neuroscience Bulletin 2024年第5期40卷 635-657页

作者： yuan Dong xia Zhang Ying Wang Neuropsychiatry Research Institute The Affiliated Hospital of Qingdao UniversityQingdao UniversityQingdao266000China Program in Cellular and Molecular Medicine Boston Children’s HospitalBostonMA02115USA

Epilepsy is a chronic neurological disorder with recurrent unprovoked seizures,affecting~65 million *** in patients with epilepsy and animal models suggests a contribution of neuroinflammation to epileptogenesis and the development of ***(ILs),as one of the major contributors to neuroinflammation,are intensively studied for their association and modulatory effects on ictogenesis and *** are commonly divided into pro-and anti-inflammatory cytokines and therefore are expected to be pathogenic or neuroprotective in ***,both protective and destructive effects have been reported for many *** may be due to the complex nature of ILs,and also possibly due to the different disease courses that those ILs are involved *** this review,we summarize the contributions of different ILs in those processes and provide a current overview of recent research advances,as well as preclinical and clinical studies targeting ILs in the treatment of epilepsy.

关键词： Epilepsy Interleukins Neuroinflammation

High-entropy design boosts dielectric energy storage

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Rare Metals 2024年第8期43卷 4013-4015页

作者： Qiu-Ying xia He Zhu si Lan Yang Ren Herbert Gleiter Institute of Nanoscience School of Materials Science and EngineeringNanjing University of Science and Technology Department of Physics City University of Hong Kong

Dielectric capacitors are vital for advanced electronic and electrical power systems due to their impressive power density and ***,a persistent challenge has been enhancing their energy densities while maintaining high *** in Science,a novel high-entropy design for relaxor ferroelectric materials has been proposed,promising significant improvements in both energy density and efficiency for multilayer dielectric ceramic *** the crucial role of high-entropy design in energy storage materials and devices,this highlight focuses on interpreting the progress and significance of this innovative work.

关键词： CERAMIC CAPACITORS DENsiTY FILMS

Multiplayer Reach-Avoid Differential Games in 3D Space Inspired by Harris'Hawks'Cooperative Hunting Tactics

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Research 2024年第2期2023卷 41-54页

作者： Wanying Ruan Haibin Duan Yongbin Sun Wanmai yuan Jie xia State Key Laboratory of Virtual Reality Technology and Systems School of Automation Science and Electrical EngineeringBeihang UniversityBeijingChina Peng Cheng Laboratory ShenzhenChina Information Science Academy of CETC BeijingChina

This paper investigates a multiplayer reach-avoid differential game in 3-dimensional(3D)space,which involves multiple pursuers,multiple evaders,and a designated target *** evaders aim to reach the target region,while the pursuers attempt to guard the target region by capturing the *** class of research holds significant practical ***,the complexity of the problem escalates substantially with the growing number of players,rendering its solution extremely *** this paper,the multiplayer game is divided into many subgames considering the cooperation among pursuers,reducing the computational burden,and obtaining numerically tractable strategies for ***,the Apollonius sphere,a fundamental geometric tool for analyzing the 3D differential game,is formulated,and its properties are *** on this,the optimal interception point for the pursuer to capture the evader is derived and the winning conditions for the pursuer and evader are ***,based on the Apollonius sphere,the optimal state feedback strategies of players are designed,and simultaneously,the optimal one-to-one pairings are ***,the Value function of the multiplayer reach-avoid differential game is explicitly given and is proved to satisfy Hamilton-Jacobi-Isaacs(HJI)***,the matching algorithm for the case with pursuers outnumbered evaders is provided through constructing a weighted bipartite graph,and the cooperative tactics for multiple pursuers are proposed,inspired by the Harris'Hawks intelligent cooperative hunting ***,numerical simulations are conducted to illustrate the effectiveness of the theoretical results for both cases where the number of adversary players is equal and unequal between the 2 groups.

关键词： holds satisfy rendering