The development of high-performance lithium-ion batteries(LIBs)hinges on searching for advanced anode materials with large specific capacities as well as high cycling stability.However,traditional graphite anodes have...The development of high-performance lithium-ion batteries(LIBs)hinges on searching for advanced anode materials with large specific capacities as well as high cycling stability.However,traditional graphite anodes have not met the demand for higher energy storage owing to the deficiency of low lithium storage capacity.In the current work,we focus on designing one composite anode material with multiscale porous(MP)structure and phosphorus(P)doping.The coupling effects of three-dimensional(3D)interconnected skeleton,hollow pore channels,and P doping can facilitate the electrolyte diffusion and the mass transfer,as well as accommodate the volume changes during lithiation/delithiation processes.As expected,the as-prepared MP-SiGeSnSbPAl composite exhibits superior lithium storage performance,achieving a specific capacity of 827.9 mAh/g after 150 cycles at 200 mA/g and maintaining the high capacity of 456.7 mAh/g after 400 cycles at 1 A/g.Contrastively,the corresponding surplus capacities are only 590.3 and 225.7 mAh/g for the non-doped counterparts,respectively.In particular,MP-SiGeSnSbPAl displays much more stable cycling performances under the measurement of high areal mass loading of~3 mg/cm^(2)and the full-cell tests with the lithium iron phosphate as the cathode.This work witnesses one scalable protocol for preparing multinary Si-based composite in terms of facile operation and high lithium storage performances.展开更多
Electrocatalytic conversion of carbon dioxide(CO_(2))into formate offers a sustainable pathway to mitigate environmental degradation and the energy crisis.Tin(Sn)-based materials are promising electrocatalysts for CO_...Electrocatalytic conversion of carbon dioxide(CO_(2))into formate offers a sustainable pathway to mitigate environmental degradation and the energy crisis.Tin(Sn)-based materials are promising electrocatalysts for CO_(2)reduction to formate;however,their efficiency is limited by weak CO_(2)adsorption and activation,as well as sluggish reaction kinetics.In this work,we designed an intercrossing nanoporous Cu_(6)Sn_(5)/Sn intermetallic heterojunction via a scalable alloying-etching protocol.The resulting Cu_(6)Sn_(5)/Sn catalyst with abundant interfacial sites exhibited enhanced formate selectivity(60.79%)at−0.93 V versus the reversible hydrogen electrode(RHE),together with a high partial current density of 12.56 mA/cm^(2)and stable operation for 16 h.The modulated electronic structure of Cu_(6)Sn_(5)coupled with the robust interfacial interaction between Sn and Cu_(6)Sn_(5)synergistically promoted CO_(2)adsorption and activation,thereby improving CO_(2)reduction reaction(CO_(2)RR)performance.Electrochemical measurements and in situ infrared spectroscopy confirmed that the dual-phase interfaces facilitate H_(2)O decomposition and the generation of abundant*H intermediates,which in turn accelerate the protonation of CO_(2)to formate.This work highlights a scalable strategy for constructing intermetallic heterojunction catalysts that combine facile synthesis,reproducibility,and superior catalytic activity for CO_(2)RR.展开更多
The development of geological lamination in shale reservoirs influences fracture propagation during hydraulic stimulation,and the fracture generation mechanism as it propagates through the laminated interface is close...The development of geological lamination in shale reservoirs influences fracture propagation during hydraulic stimulation,and the fracture generation mechanism as it propagates through the laminated interface is closely related to fracturing effects.In this paper,the laminated shale was selected to conduct three-point bending experiments using digital image correlation(DIC)and acoustic emission(AE)techniques,which revealed that the propagation path of cross-layer fractures exhibits dislocation features.The cohesive fracture mechanism of cross-layer fractures is investigated from the viewpoint of the fracture process zone(FPZ),which displays the characteristics of intermittence and dislocation during fracture development.A computational criterion for predicting the dislocation of cross-layer fracture at the interface is proposed,which shows that the maximum dislocation range does not exceed 72%of the FPZ length.Considering the mechanical differences between adjacent layers of laminated shale,the cohesive zone model of cross-layer fracture is discussed,from which the constitutive relationship and fracture energy during FPZ development are characterized,and the discontinuous nature of the constitutive relationship is found.This study improves the understanding of the geometry and cohesive fracture mechanism of the cross-layer fracture and provides valuable insights for field fracturing in shale reservoirs.展开更多
Volatile organic compounds(VOCs)are important precursors of secondary organic compounds and ozone,which raise major environmental concerns.To investigate the VOC emission characteristics,measurements of VOCs based on ...Volatile organic compounds(VOCs)are important precursors of secondary organic compounds and ozone,which raise major environmental concerns.To investigate the VOC emission characteristics,measurements of VOCs based on proton transfer reaction-mass spectrometry during 2017 were conducted in a coastal industrial area in Ningbo,Zhejiang Province,China.Based on seasonal variation in species concentration,the positive matrix factorization(PMF)receptor model was applied to apportion the sources of VOCs in each season.The PMF results revealed that unknown acetonitrile source,paint solvent,electronics industry,biomass burning,secondary formation and biogenic emission were mainly attributed to VOC pollution.Biomass burning and secondary formation were the major sources of VOCs and contributed more than 70%of VOC emissions in spring and autumn.Industry-related sources contributed 8.65%–31.2%of the VOCs throughout the year.The unknown acetonitrile source occurred in winter and spring,and contributed 7.6%–43.73%of the VOC emissions in the two seasons.Conditional probability function(CPF)analysis illustrated that the industry sources came from local emission,while biomass burning and biogenic emission mainly came from the northwest direction.The potential source contribution function(PSCF)model showed that secondary formation-related source was mainly from Jiangsu Province,northeastern China and the surrounding ocean.The potential source areas of unknown acetonitrile source were northern Zhejiang Province,southern Jiangsu Province and the northeastern coastal marine environments.展开更多
Based on the carbon isotope record of organic matter from the Yuanbao loess section, northwestern China, five enhanced summer monsoon events were observed at this area during the Last Interglaciation. Such events were...Based on the carbon isotope record of organic matter from the Yuanbao loess section, northwestern China, five enhanced summer monsoon events were observed at this area during the Last Interglaciation. Such events were also recorded by the paleosol layers, pollen assemblage and magnetic susceptibility. It is suggested that the enhanced summer monsoon leads to the shift of vegetation type, which results in the change of δ13C value of organic matter in the paleosol layer. It appears that the δ13C of organic matter is a good indicator for the summer monsoon variation. Among these five events, the first, second and the fifth reached their maximum smoothly, but the other two had experienced a less cold stage before reaching their peaks, which suggests that the mechanisms of such events may be different.展开更多
基金supported by National Science Foundation of Shandong Province(Nos.ZR2023ME155 and ZR2023ME085)the Taishan Scholar Project of Shandong Province(Nos.tsqn202306226 and tsqn202211171).
文摘The development of high-performance lithium-ion batteries(LIBs)hinges on searching for advanced anode materials with large specific capacities as well as high cycling stability.However,traditional graphite anodes have not met the demand for higher energy storage owing to the deficiency of low lithium storage capacity.In the current work,we focus on designing one composite anode material with multiscale porous(MP)structure and phosphorus(P)doping.The coupling effects of three-dimensional(3D)interconnected skeleton,hollow pore channels,and P doping can facilitate the electrolyte diffusion and the mass transfer,as well as accommodate the volume changes during lithiation/delithiation processes.As expected,the as-prepared MP-SiGeSnSbPAl composite exhibits superior lithium storage performance,achieving a specific capacity of 827.9 mAh/g after 150 cycles at 200 mA/g and maintaining the high capacity of 456.7 mAh/g after 400 cycles at 1 A/g.Contrastively,the corresponding surplus capacities are only 590.3 and 225.7 mAh/g for the non-doped counterparts,respectively.In particular,MP-SiGeSnSbPAl displays much more stable cycling performances under the measurement of high areal mass loading of~3 mg/cm^(2)and the full-cell tests with the lithium iron phosphate as the cathode.This work witnesses one scalable protocol for preparing multinary Si-based composite in terms of facile operation and high lithium storage performances.
基金supported by Natural Science Foundation of Shandong Province(No.ZR2023ME155)the project of“20 Items of University”of Jinan(No.202228046)the Tais-han Scholar Project of Shandong Province(Nos.tsqn202306226 and tsqn202211171).
文摘Electrocatalytic conversion of carbon dioxide(CO_(2))into formate offers a sustainable pathway to mitigate environmental degradation and the energy crisis.Tin(Sn)-based materials are promising electrocatalysts for CO_(2)reduction to formate;however,their efficiency is limited by weak CO_(2)adsorption and activation,as well as sluggish reaction kinetics.In this work,we designed an intercrossing nanoporous Cu_(6)Sn_(5)/Sn intermetallic heterojunction via a scalable alloying-etching protocol.The resulting Cu_(6)Sn_(5)/Sn catalyst with abundant interfacial sites exhibited enhanced formate selectivity(60.79%)at−0.93 V versus the reversible hydrogen electrode(RHE),together with a high partial current density of 12.56 mA/cm^(2)and stable operation for 16 h.The modulated electronic structure of Cu_(6)Sn_(5)coupled with the robust interfacial interaction between Sn and Cu_(6)Sn_(5)synergistically promoted CO_(2)adsorption and activation,thereby improving CO_(2)reduction reaction(CO_(2)RR)performance.Electrochemical measurements and in situ infrared spectroscopy confirmed that the dual-phase interfaces facilitate H_(2)O decomposition and the generation of abundant*H intermediates,which in turn accelerate the protonation of CO_(2)to formate.This work highlights a scalable strategy for constructing intermetallic heterojunction catalysts that combine facile synthesis,reproducibility,and superior catalytic activity for CO_(2)RR.
基金financiallysupported by the Excellent Young Fund of Sinopec Petroleum Exploration and Production Research Institute(Grant No.YK2024009)the National Natural Science Foundation of China(Grant Nos.U23B6004 and 51925405).
文摘The development of geological lamination in shale reservoirs influences fracture propagation during hydraulic stimulation,and the fracture generation mechanism as it propagates through the laminated interface is closely related to fracturing effects.In this paper,the laminated shale was selected to conduct three-point bending experiments using digital image correlation(DIC)and acoustic emission(AE)techniques,which revealed that the propagation path of cross-layer fractures exhibits dislocation features.The cohesive fracture mechanism of cross-layer fractures is investigated from the viewpoint of the fracture process zone(FPZ),which displays the characteristics of intermittence and dislocation during fracture development.A computational criterion for predicting the dislocation of cross-layer fracture at the interface is proposed,which shows that the maximum dislocation range does not exceed 72%of the FPZ length.Considering the mechanical differences between adjacent layers of laminated shale,the cohesive zone model of cross-layer fracture is discussed,from which the constitutive relationship and fracture energy during FPZ development are characterized,and the discontinuous nature of the constitutive relationship is found.This study improves the understanding of the geometry and cohesive fracture mechanism of the cross-layer fracture and provides valuable insights for field fracturing in shale reservoirs.
基金supported by the National Nature Science Foundation for Young Scientists of China(Nos.41605094,41905115).
文摘Volatile organic compounds(VOCs)are important precursors of secondary organic compounds and ozone,which raise major environmental concerns.To investigate the VOC emission characteristics,measurements of VOCs based on proton transfer reaction-mass spectrometry during 2017 were conducted in a coastal industrial area in Ningbo,Zhejiang Province,China.Based on seasonal variation in species concentration,the positive matrix factorization(PMF)receptor model was applied to apportion the sources of VOCs in each season.The PMF results revealed that unknown acetonitrile source,paint solvent,electronics industry,biomass burning,secondary formation and biogenic emission were mainly attributed to VOC pollution.Biomass burning and secondary formation were the major sources of VOCs and contributed more than 70%of VOC emissions in spring and autumn.Industry-related sources contributed 8.65%–31.2%of the VOCs throughout the year.The unknown acetonitrile source occurred in winter and spring,and contributed 7.6%–43.73%of the VOC emissions in the two seasons.Conditional probability function(CPF)analysis illustrated that the industry sources came from local emission,while biomass burning and biogenic emission mainly came from the northwest direction.The potential source contribution function(PSCF)model showed that secondary formation-related source was mainly from Jiangsu Province,northeastern China and the surrounding ocean.The potential source areas of unknown acetonitrile source were northern Zhejiang Province,southern Jiangsu Province and the northeastern coastal marine environments.
基金This work was supported by the State Key Basic Research Development Project (Grant No. G1999043401) the Knowledge Innovation Project of the Chinese Academy of Sciences (Grant No. KZCX-Y-05).
文摘Based on the carbon isotope record of organic matter from the Yuanbao loess section, northwestern China, five enhanced summer monsoon events were observed at this area during the Last Interglaciation. Such events were also recorded by the paleosol layers, pollen assemblage and magnetic susceptibility. It is suggested that the enhanced summer monsoon leads to the shift of vegetation type, which results in the change of δ13C value of organic matter in the paleosol layer. It appears that the δ13C of organic matter is a good indicator for the summer monsoon variation. Among these five events, the first, second and the fifth reached their maximum smoothly, but the other two had experienced a less cold stage before reaching their peaks, which suggests that the mechanisms of such events may be different.
