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Lattice-mismatch-induced formation of defect-rich Pd-Cu alloy nanocages for enhanced formic acid oxidation activity

SCIENCE CHINA-CHEMISTRY 2025年第2期68卷 481-491页

作者： Liu, Zhaojun Wang, Zhengyan Wang, Zhaoyu Yuan, Hao bai, yuke Wang, Xiaoxiao Mu, Zerui Wu, Chunxia Liu, Kai Hu, Zhun Gao, Chuanbo Xi An Jiao Tong Univ Frontier Inst Sci & Technol Sate Key Lab Multiphase Flow Power Engn Xian 710049 Peoples R China Xi An Jiao Tong Univ Inst Ind Catalysis Sch Chem Engn & Technol Xian 710049 Peoples R China

Crystallographic defects in noble metal nanocrystals are recognized as highly active catalytic sites, significantly enhancing activities in many important reactions. Despite their importance, synthesizing noble metal nanocrystals with a high density of defects poses a considerable synthetic challenge. Here, we present a novel lattice mismatch-induced formation mechanism to create high-density defects in noble metal nanocrystals. This approach takes advantage of lattice mismatch to enable non-epitaxial nucleation and growth of a noble metal on a foreign metal substrate, forming abundant noble metal crystallites with random lattice orientations not dictated by the substrate lattice. As these crystallites grow extensively, they merge, forming numerous grain boundaries and yielding defect-rich noble metal nanocrystals. Defect-rich alloy nanocrystals can also be synthesized through a subsequent vacancy-diffusion alloying process. We take defective PdCu alloy nanocages as an example and demonstrate the effectiveness of crystallographic defects in enhancing catalytic performance of noble metal nanocrystals. The nanocages exhibit superior activity in the electrocatalytic formic acid oxidation reaction, which is 1.6 times greater than their defect-free counterparts. Our strategy offers a new avenue for creating defect-rich noble metal nanocrystals as highly efficient catalysts for a wide array of catalytic applications.

关键词： noble metal nanocrystals defects non-epitaxial growth electrocatalysis formic acid oxidation reaction

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Lattice-mismatch-induced formation of defect-rich Pd–Cu alloy nanocages for enhanced formic acid oxidation activity

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Science China Chemistry 2025年第2期 481-491页

作者： Zhaojun Liu Zhengyan Wang Zhaoyu Wang Hao Yuan yuke bai Xiaoxiao Wang Zerui Mu Chunxia Wu Kai Liu Zhun Hu Chuanbo Gao Sate Key Laboratory of Multiphase Flow in Power Engineering Frontier Institute of Science and TechnologyXi'an Jiaotong University Institute of Industrial Catalysis School of Chemical Engineering and TechnologyXi'an Jiaotong University

Crystallographic defects in noble metal nanocrystals are recognized as highly active catalytic sites, significantly enhancing activities in many important reactions. Despite their importance, synthesizing noble metal nanocrystals with a high density of defects poses a considerable synthetic challenge. Here, we present a novel lattice mismatch-induced formation mechanism to create high-density defects in noble metal nanocrystals. This approach takes advantage of lattice mismatch to enable nonepitaxial nucleation and growth of a noble metal on a foreign metal substrate, forming abundant noble metal crystallites with random lattice orientations not dictated by the substrate lattice. As these crystallites grow extensively, they merge, forming numerous grain boundaries and yielding defect-rich noble metal nanocrystals. Defect-rich alloy nanocrystals can also be synthesized through a subsequent vacancy-diffusion alloying process. We take defective Pd Cu alloy nanocages as an example and demonstrate the effectiveness of crystallographic defects in enhancing catalytic performance of noble metal *** nanocages exhibit superior activity in the electrocatalytic formic acid oxidation reaction, which is 1.6 times greater than their defect-free counterparts. Our strategy offers a new avenue for creating defect-rich noble metal nanocrystals as highly efficient catalysts for a wide array of catalytic applications.

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Spatiotemporal variation and driving factors of vegetation net primary productivity in the Guan-zhong Plain Urban Agglomeration,China from 2001 to 2020

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Journal of Arid Land 2025年第1期17卷 74-92页

作者： LIU yuke HUANG Chenlu YANG Chun CHEN Chen School of Tourism&Research Institute of Human Geography Xi'an International Studies UniversityXi'an 710128China

Studying the spatiotemporal variation and driving mechanisms of vegetation net primary productivity(NPP)in the Guanzhong Plain Urban Agglomeration(GPUA)of China is highly important for regional green and low-carbon *** study used the Theil-Sen trend analysis,Mann-Kendall trend test,coefficient of variation,Hurst index,and machine learning method(eXtreme Gradient Boosting and SHapley Additive exPlanations(XGBoost-SHAP))to analyze the spatiotemporal variation of NPP in the GPUA from 2001 to 2020 and reveal its response to climate change and human *** results found that during 2001-2020,the averageNPP in the GPUA showed a significant upward trend,with an annual growth rate of 10.84 g C/(m^(2)•a).The multi-year average NPP in the GPUA was 484.83 g C/(m^(2)•a),with higher values in the southwestern Qinling Mountains and lower values in the central and northeastern cropland and built-up *** average coefficient of variation of NPP in the GPUA was 0.14,indicating a relatively stable state overall,but 72.72%of the study area showed weak anti-persistence,suggesting that NPP in most areas may have declined in the short *** to XGBoost-SHAP analyses,elevation,land use type and precipitation were identified as the main driving factors of *** precipitation and higher temperatures promote NPP growth,whereas extreme climates,high population density,and nighttime lighting inhibit *** study has important theoretical and practical significance for achieving regional sustainable development,offers a scientific basis for formulating effective ecological protection and restoration strategies,and promotes green,coordinated,and sustainable development in the GPUA.

关键词： net primary productivity(NPP) Theil-Sen trend analysis machine learning climate change urbanization Guanzhong Plain Urban Agglomeration(GPUA)

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Disordered hyperuniformity and thermal transport in monolayer amorphous carbon

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Science China(Physics,Mechanics & Astronomy) 2025年第2期68卷 145-152页

作者： Nianjie Liang Yuxi Wang bai Song Department of Energy and Resources Engineering Peking UniversityBeijing 100871China Department of Advanced Manufacturing and Robotics Peking UniversityBeijing 100871China

Disordered hyperuniformity(DHU)is a recently discovered novel state of amorphous systems characterized by strongly suppressed density fluctuations at large length scales as in crystalline materials,which offers great potential for achieving unusual mechanical,electronic,and photonic ***,despite the fundamental and technological importance of thermal transport in amorphous solids,the effect of DHU remains largely ***,we theoretically study thermal transport in a class of two-dimensional DHU materials—monolayer amorphous carbon(MAC).Beginning with a perfect graphene lattice,we continuously apply Stone-Wales transformations to generate a series of MAC models with varied degrees of disorder and defects,which are quantified through comprehensive structural analysis including the so-called hyperuniformity index(H),where a smaller H indicates a higher degree of ***,we conduct molecular dynamics simulations to obtain the thermal conductivity(κ).A significant correlation between the thermal transport behavior and degree of hyperuniformity is observed,with the room-temperatureκdecreasing from 26.3 to 5.3 W m^(-1)K^(-1)while H is tuned from 0.0004 to ***,two distinct transport regimes are identified,including a nearly-DHU regime at small H(<0.005)whereκdrops sharply and a non-DHU region at larger H whereκbecomes relatively ***-resolved analysis reveals longer lifetime and higher participation ratio for the heat carriers in nearly-DHU MAC,implying that the hidden long-range correlations could support extended modes that enhance *** work highlights the impact of DHU on the thermal properties of amorphous materials and represents a conceptual advancement that is worthy of future exploration.

关键词： disordered hyperuniformity thermal transport amorphous material two-dimensional monolayer amorphous carbon

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Anisotropic transport properties and topological Hall effect in the annealed kagome antiferromagnet FeGe

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Science China(Physics,Mechanics & Astronomy) 2025年第3期Mechanics & Astronomy) .卷 157-164页

作者： Jiajun Ma Chenfei Shi Yantao Cao Yuwei Zhang Yazhou Li Jiaxing Liao Jialu Wang Wenhe Jiao Hanjie Guo Chenchao Xu Shixun Cao Jianhui Dai Jin-Ke Bao yuke Li School of Physics Hangzhou Key Laboratory of Quantum Matters Hangzhou Normal University Department of Physics Materials Genome Institute and International Center for Quantum and Molecular StructuresShanghai University Songshan Lake Materials Laboratory School of Physical Science and Technology Lanzhou University Key Laboratory of Quantum Precision Measurement of Zhejiang Province Department of Applied PhysicsZhejiang University of Technology

Electron correlation often gives birth to various orders in quantum ***,a strongly correlated kagome antiferromagnet Fe Ge is discovered to undergo a charge density wave transition inside the A-type antiferromagnetic state,providing an opportunity to explore the interplay between charge order and ***,we reported the observation of anisotropic resistivity and Hall effect,along with a topological Hall effect,in the annealed Fe Ge *** the current flows along the abplane,the temperature dependence ofρabexhibits a distinct resistivity loop related to a first-order transition at *** applied magnetic fields do not alter Tcdwbut can induce a spin-flop transition at ***,a field-induced large topological Hall effect is observed in the canting antiferromagnetic （CAFM） state below Tcant,which is possibly attributed to the non-trivial spin texture during the spin-flop ***,as current is parallel to c-axis,both the field-induced transitions inρcandχ***,the Hall resistivity in the annealed Fe Ge significantly exhibits a deviation from the linear *** findings provide valuable insight into revealing the interplay among magnetism,charge order and topology in the kagome magnets.

关键词： charge density wave Hall effect transport properties kagome magnet

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An improved GCN−TCN−AR model for PM_(2.5) predictions in the arid areas of Xinjiang,China

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Journal of Arid Land 2025年第1期17卷 93-111页

作者： CHEN Wenqian bai Xuesong ZHANG Na CAO Xiaoyi School of Information and Control Engineering Qingdao University of TechnologyQingdao 266520China Key Laboratory for Semi-Arid Climate Change of the Ministry of Education College of Atmospheric SciencesLanzhou UniversityLanzhou 730000China

As one of the main characteristics of atmospheric pollutants,PM_(2.5) severely affects human health and has received widespread attention in recent *** to predict the variations of PM_(2.5) concentrations with high accuracy is an important *** PM_(2.5) monitoring stations in Xinjiang Uygur Autonomous Region,China,are unevenly distributed,which makes it challenging to conduct comprehensive analyses and ***,this study primarily addresses the limitations mentioned above and the poor generalization ability of PM_(2.5) concentration prediction models across different monitoring *** chose the northern slope of the Tianshan Mountains as the study area and took the January−December in 2019 as the research *** the basis of data from 21 PM_(2.5) monitoring stations as well as meteorological data(temperature,instantaneous wind speed,and pressure),we developed an improved model,namely GCN−TCN−AR(where GCN is the graph convolution network,TCN is the temporal convolutional network,and AR is the autoregression),for predicting PM_(2.5) concentrations on the northern slope of the Tianshan *** GCN−TCN−AR model is composed of an improved GCN model,a TCN model,and an AR *** results revealed that the R2 values predicted by the GCN−TCN−AR model at the four monitoring stations(Urumqi,Wujiaqu,Shihezi,and Changji)were 0.93,0.91,0.93,and 0.92,respectively,and the RMSE(root mean square error)values were 6.85,7.52,7.01,and 7.28μg/m^(3),*** performance of the GCN−TCN−AR model was also compared with the currently neural network models,including the GCN−TCN,GCN,TCN,Support Vector Regression(SVR),and *** GCN−TCN−AR outperformed the other current neural network models,with high prediction accuracy and good stability,making it especially suitable for the predictions of PM_(2.5)*** study revealed the significant spatiotemporal variations of PM_(2.5)***,the PM_(2.5) concentrations exhibited cle

关键词： air pollution PM_(2.5) concentrations graph convolution network(GCN)model temporal convolutional network(TCN)model autoregression(AR)model northern slope of the Tianshan Mountains

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Protonated carbon nitride for rapid photocatalytic sterilization via synergistic oxidative damage and physical destruction

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Journal of Environmental Sciences 2025年第3期149卷 188-199页

作者： Xiaobiao Zhu Chunhong Xu Jie Mao Yizhen Zhang Yaohui bai Department of Environmental Science and Engineering College of Chemical EngineeringBeijing University of Chemical TechnologyBeijing 100029China Research Center for Eco-Environmental Sciences Chinese Academy of SciencesBeijing 100085China College of Safety and Environmental Engineering Shandong University of Science and TechnologyQingdao 266590China

Photocatalytic disinfection is an eco-friendly strategy for countering bacterial pollution in aquatic *** strategies have been devised to facilitate the generation of reactive oxygen species(ROS)within photocatalysts,ultimately leading to the eradication of ***,the significance of the physical morphology of photocatalysts in the context of sterilization is frequently obscured,and the progress in the development of physical-chemical synergistic sterilization photocatalysts has been relatively ***,graphitic carbon nitride(g-C_(3)N_(4))is chemically protonated to expose more sharp *** fluorescence and EIS results indicate that the protonation can accelerate photogenerated carrier separation and enhance ROS ***,the sharp edges on the protonated g-C_(3)N_(4)facilitate the physical disruption of cell walls for further promoting oxidative *** C_(3)N_(4)demonstrated superior bactericidal performance than that of pristine g-C_(3)N_(4),effectively eliminating Escherichia coli within 40 minutes under *** work highlights the significance of incorporating physical and chemical synergies in photocatalyst design to enhance the disinfection efficiency of photocatalysis.

关键词： Protonated Photocatalytic Sterilization Synergistic Oxidative Damage Physical Destruction

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The transformation of nor-seco-cucurbit[10]uril to cucurbit[5]uril and cucurbit[8]uril controlled by its own concentration

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Chinese Chemical Letters 2025年第2期36卷 373-377页

作者： Shaojie Deng Peihua Ma Qinghong bai Xin Xiao Key Laboratory of Macrocyclic and Supramolecular Chemistry of Guizhou Province Department of Chemistry Guizhou University

Nor-seco-cucurbit[10]uril(ns-CB[10]) is a kinetic product with unique structure. The single bridged methylene in its structure makes the molecular cavity of ns-CB[10] more deformable when compared to ordinary cucurbit[n]uril, reducing its structural stability. Repeated experiments showed that ns-CB[10] gradually cracks in an acidic solution and changes the specificity of cucurbit[5]uril(CB[5]) and cucurbit[8]uril(CB[8]) under more robust acidic solutions and when heated. A series of experiments were designed to study the transformation behavior of ns-CB[10]. It was found that the concentration of ns-CB[10] was correlated with the content distribution of CB[5] and CB[8]. This study explores the influencing factors and mechanisms of the transformation of ns-CB[10] to CB[5] and CB[8]. The results are of great significance for the application of ns-CB[10], understanding the formation mechanism of cucurbit[n]urils. Furthermore,it provides a new pathway for synthesizing new cucurbit[n]urils.

关键词： Concentration control Cracking Mechanism Nor-seco-cucurbituril Transformation

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基于改进的TF-IDF标签权重算法的电商用户画像构建

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信息技术与信息化 2024年第8期 48-51页

作者：白雨珂卢胜男西安石油大学陕西西安710065

在电商环境中,用户画像构建是为了更好地理解和满足用户需求而进行的重要任务。传统的TF-IDF标签权重计算方法无法很好地对标签权重进行调整,为了解决这一问题,提出基于TF-IDF算法的改进方法,旨在提高用户画像的准确性和个性化程度。融... 详细信息

在电商环境中,用户画像构建是为了更好地理解和满足用户需求而进行的重要任务。传统的TF-IDF标签权重计算方法无法很好地对标签权重进行调整,为了解决这一问题,提出基于TF-IDF算法的改进方法,旨在提高用户画像的准确性和个性化程度。融合相关系数矩阵,对相关性强的标签进行适当降权操作。不同类型的行为对标签信息产生不同的权重,并且标签的权重可能会随着时间的推移而衰减。因此,采用拟合记忆遗忘曲线模拟得到的兴趣遗忘曲线,对用户画像权重进行调优操作。实验结果表明,使用所提出的改进的TF-IDF算法构建用户画像的效果得到显著的提升。

关键词：电商相关系数标签权重用户画像 TF-IDF算法

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Gas-Solid Flow,Combustion Characteristics,and Gas Emissions in a 75 t/h CFB Boiler Based on the CPFD Method

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Journal of Thermal Science 2025年第1期34卷 323-336页

作者： HUANG Xiankun bai Zhang ZHU Xiaoli WANG Shuoshuo MU Lin GONG Liang College of New Energy China University of Petroleum(East China)Qingdao 266580China Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education School of Energy and Power EngineeringDalian University of TechnologyDalian 116024China

A 3D simulation using Computational Particle Fluid Dynamics(CPFD)methods was used to calculate coal combustion in a 75 t/h industrial-scale circulating fluidized bed(CFB)*** characteristics,gas-solid flow characteristics,and gaseous pollutant emissions of CFB boilers from combustion ignition to stable operation were systematically evaluated in this *** show that the temperature distribution is relatively uniform throughout the *** the combustion process unfolds within the boiler,the gas composition curve strikingly portrays the inverse correlation between CO_(2)and O_(2)*** the combustion reaction progresses,it becomes evident that the concentration of CO_(2)progressively increases,while the concentration of O_(2)concurrently *** inverse relationship underscores the fundamental combustion reaction,where carbon-based fuels react with oxygen to produce carbon dioxide and release ***,a comprehensive analysis has revealed that,from ignition to stable combustion,both nitric oxide(NO)and sulfur dioxide(SO_(2))emissions exhibit a declining *** reduction in pollutant generation is attributed to the improvement in combustion *** complete combustion leads to lower levels of unburned hydrocarbons,which are prone to NO ***,the sulfur content in the fuel is more efficiently oxidized to sulfur trioxide(SO_(3))or bound in sulfates,reducing SO_(2)*** steady state in the simulation,the SO_(2)mass flow rate varies significantly with the furnace height,gradually increasing from 0.07 kg·s^(-1)at 4 m at the bottom of the furnace to a peak of 0.078 kg·s^(-1)at 8 m in the center,and then decreasing to 0.06 kg·s^(-1)at 20m at the top of the furnace.

关键词： circulating fluidized bed particle flow combustion CPFD modeling

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