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Synthesis of Core-shell ZSM-5@ Ordered Mesoporous Silica by Tetradecylamine Surfactant
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作者 马扩彦 ZHAO Pengxian +4 位作者 YI Hongyu 俞海军 ZHOU Moxi ZHANG Lingling LIU Yupu 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第2期332-336,共5页
A core-shell composite consisting of ZSM-5 zeolite as the core and ordered mesoporous silica as the shell was prepared by a surfactant-controlled sol-gel process and using tetradecylamine(TDA) as the template and Tetr... A core-shell composite consisting of ZSM-5 zeolite as the core and ordered mesoporous silica as the shell was prepared by a surfactant-controlled sol-gel process and using tetradecylamine(TDA) as the template and Tetraethylorthosilicate(TEOS) as the silica precursor.The pores of the silica shell were found to be ordered and perpendicular to the crystal faces of the zeolite core.The thickness of the shell in the coreshell structured composite can be adjusted in the range of 20-90 nm,while the surface morphology and the pore size distribution were modified by changing the mass ratio of TEOS to zeolite.The composite molecular sieves have higher surface area for capturing molecules than ZSM-5,and with the increase of mesoporous shell layer,the ZSM-5@SiO_(2)-x composites show stronger adsorption capacity of butyraldehyde.However,when the shell thickness exceeds 90 nm,the adsorption capacity of butyraldehyde decreases instead.The composites have a huge potential for environmental applications. 展开更多
关键词 core-shell COMPOSITE tetradecylamine SURFACTANT ADSORPTION
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Core-Shell Semiconductor-Graphene Nanoarchitectures for Efficient Photocatalysis:State of the Art and Perspectives
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作者 Jinshen Lan Shanzhi Qu +6 位作者 Xiaofang Ye Yifan Zheng Mengwei Ma Shengshi Guo Shengli Huang Shuping Li Junyong Kang 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第12期553-588,共36页
Semiconductor photocatalysis holds great promise for renewable energy generation and environment remediation,but generally suffers from the serious drawbacks on light absorption,charge generation and transport,and str... Semiconductor photocatalysis holds great promise for renewable energy generation and environment remediation,but generally suffers from the serious drawbacks on light absorption,charge generation and transport,and structural stability that limit the performance.The core-shell semiconductorgraphene(CSSG)nanoarchitectures may address these issues due to their unique structures with exceptional physical and chemical properties.This review explores recent advances of the CSSG nanoarchitectures in the photocatalytic performance.It starts with the classification of the CSSG nanoarchitectures by the dimensionality.Then,the construction methods under internal and external driving forces were introduced and compared with each other.Afterward,the physicochemical properties and photocatalytic applications of these nanoarchitectures were discussed,with a focus on their role in photocatalysis.It ends with a summary and some perspectives on future development of the CSSG nanoarchitectures toward highly efficient photocatalysts with extensive application.By harnessing the synergistic capabilities of the CSSG architectures,we aim to address pressing environmental and energy challenges and drive scientific progress in these fields. 展开更多
关键词 core-shell semiconductor-graphene Nanoarchitecture PHOTOCATALYSIS Driving force Interface
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Recent advances in core-shell organic framework-based photocatalysts for energy conversion and environmental remediation
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作者 Qibing Dong Ximing Li +9 位作者 Yanyan Duan Qingyun Tian Xinxin Liang Yiyin Zhu Lin Tian Junjun Wang Atif Sial Yongqian Cui Ke Zhao Chuanyi Wang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第8期168-199,I0004,共33页
Direct conversion of solar energy into chemical energy in an environmentally friendly manner is one of the most promising strategies to deal with the environmental pollution and energy crisis.Among a variety of materi... Direct conversion of solar energy into chemical energy in an environmentally friendly manner is one of the most promising strategies to deal with the environmental pollution and energy crisis.Among a variety of materials developed as photocatalysts,the core-shell metal/covalent-organic framework(MOF or COF)photocatalysts have garnered significant attention due to their highly porous structure and the adjustability in both structure and functionality.The existing reviews on core-shell organic framework photocatalytic materials have mainly focused on core-shell MOF materials.However,there is still a lack of indepth reviews specifically addressing the photocatalytic performance of core-shell COFs and MOFs@COFs.Simultaneously,there is an urgent need for a comprehensive review encompassing these three types of core-shell structures.Based on this,this review aims to provide a comprehensive understanding and useful guidelines for the exploration of suitable core-shell organic framework photocatalysts towards appropriate photocatalytic energy conversion and environmental governance.Firstly,the classification,synthesis,formation mechanisms,and reasonable regulation of core-shell organic framework were summarized.Then,the photocatalytic applications of these three kinds of core-shell structures in different areas,such as H_(2)evolution,CO_(2)reduction,and pollutants degradation are emphasized.Finally,the main challenges and development prospects of core-shell organic framework photocatalysts were introduced.This review aims to provide insights into the development of a novel generation of efficient and stable core-shell organic framework materials for energy conversion and environmental remediation. 展开更多
关键词 Organic framework core-shell structure PHOTOCATALYSIS Energy conversion Environmental remediation
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Amorphous core-shell NiMoP@CuNWs rod-like structure with hydrophilicity feature for efficient hydrogen production in neutral media
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作者 Jiayong Xiao Chao Jiang +3 位作者 Hui Zhang Zhuo Xing Ming Qiu Ying Yu 《Chinese Journal of Catalysis》 SCIE CAS CSCD 2024年第8期154-163,共10页
Using interface engineering,a highly efficient catalyst with a shell@core structure was successfully synthesized by growing an amorphous material composed of Ni,Mo,and P on Cu nanowires(Ni-MoP@CuNWs).This catalyst onl... Using interface engineering,a highly efficient catalyst with a shell@core structure was successfully synthesized by growing an amorphous material composed of Ni,Mo,and P on Cu nanowires(Ni-MoP@CuNWs).This catalyst only requires an overpotential of 35 mV to reach a current density of 10 mA cm^(-2).The exceptional hydrogen evolution reaction(HER)activity is attributed to the unique amorphous rod-like nature of NiMoP@CuNWs,which possesses a special hydrophilic feature,en-hances mass transfer,promotes effective contact between the electrode and electrolyte solution,and exposes more active sites during the catalytic process.Density functional theory revealed that the introduction of Mo weakens the binding strength of the Ni site on the catalyst surface with the H atom and promotes the desorption process of the H_(2) product significantly.Owing to its facile syn-thesis,low cost,and high catalytic performance,this electrocatalyst is a promising option for com-mercial applications as a water electrolysis catalyst. 展开更多
关键词 AMORPHOUS Three-dimensional core-shell Electrodeposition Neutral electrolyte ELECTROCATALYST Hydrogen evolution reaction
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A novel Ag/ZnO core-shell structure for efficient sterilization synergizing antibiotics and subsequently removing residuals
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作者 Wenmei Han Wenli Wang +4 位作者 Jie Fan Runping Jia Xuchun Yang Tong Wu Qingsheng Wu 《Green Energy & Environment》 SCIE EI CAS CSCD 2024年第2期366-377,共12页
The massive use of antibiotics has led to the aggravation of bacterial resistance and also brought environmental pollution problems.This poses a great threat to human health.If the dosage of antibiotics is reduced by ... The massive use of antibiotics has led to the aggravation of bacterial resistance and also brought environmental pollution problems.This poses a great threat to human health.If the dosage of antibiotics is reduced by increasing its bactericidal performance,the emergence of drug resistance is certainly delayed,so that there's not enough time for developing drug resistance during treatment.Therefore,we selected typical representative materials of metal Ag and semiconductor ZnO nano-bactericides to design and synthesize Ag/ZnO hollow core-shell structures(AZ for short).Antibiotics are grafted on the surface of AZ through rational modification to form a composite sterilization system.The research results show that the antibacterial efficiency of the composite system is significantly increased,from the sum(34.7%+22.8%-57.5%)of the antibacterial efficiency of AZ and gentamicin to 80.2%,net synergizes 22.7%,which fully reflects the effect of 1+1>2.Therefore,the dosage of antibiotics can be drastically reduced in this way,which makes both the possibility of bacterial resistance and medical expenses remarkably decrease.Subsequently,residual antibiotics can be degraded under simple illumination using AZ-self as a photocatalyst,which cuts off the path of environmental pollution.In short,such an innovative route has guiding significance for drug resistance. 展开更多
关键词 Ag/ZnO hollow core-shell structures ANTIBIOTICS GENTAMYCIN Synergistic sterilization PHOTODEGRADATION
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Exploring the Core-shell Structure of BaTiO3-based Dielectric Ceramics Using Machine Learning Models and Interpretability Analysis
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作者 孙家乐 XIONG Peifeng +1 位作者 郝华 LIU Hanxing 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第3期561-569,共9页
A machine learning(ML)-based random forest(RF)classification model algorithm was employed to investigate the main factors affecting the formation of the core-shell structure of BaTiO_(3)-based ceramics and their inter... A machine learning(ML)-based random forest(RF)classification model algorithm was employed to investigate the main factors affecting the formation of the core-shell structure of BaTiO_(3)-based ceramics and their interpretability was analyzed by using Shapley additive explanations(SHAP).An F1-score changed from 0.8795 to 0.9310,accuracy from 0.8450 to 0.9070,precision from 0.8714 to 0.9000,recall from 0.8929 to 0.9643,and ROC/AUC value of 0.97±0.03 was achieved by the RF classification with the optimal set of features containing only 5 features,demonstrating the high accuracy of our model and its high robustness.During the interpretability analysis of the model,it was found that the electronegativity,melting point,and sintering temperature of the dopant contribute highly to the formation of the core-shell structure,and based on these characteristics,specific ranges were delineated and twelve elements were finally obtained that met all the requirements,namely Si,Sc,Mn,Fe,Co,Ni,Pd,Er,Tm,Lu,Pa,and Cm.In the process of exploring the structure of the core-shell,the doping elements can be effectively localized to be selected by choosing the range of features. 展开更多
关键词 machine learning BaTiO_(3) core-shell structure random forest classifier
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Interfacial reinforcement of core-shell HMX@energetic polymer composites featuring enhanced thermal and safety performance
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作者 Binghui Duan Hongchang Mo +3 位作者 Bojun Tan Xianming Lu Bozhou Wang Ning Liu 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第1期387-399,共13页
The weak interface interaction and solid-solid phase transition have long been a conundrum for 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane(HMX)-based polymer-bonded explosives(PBX).A two-step strategy that involves... The weak interface interaction and solid-solid phase transition have long been a conundrum for 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane(HMX)-based polymer-bonded explosives(PBX).A two-step strategy that involves the pretreatment of HMX to endow—OH groups on the surface via polyalcohol bonding agent modification and in situ coating with nitrate ester-containing polymer,was proposed to address the problem.Two types of energetic polyether—glycidyl azide polymer(GAP)and nitrate modified GAP(GNP)were grafted onto HMX crystal based on isocyanate addition reaction bridged through neutral polymeric bonding agent(NPBA)layer.The morphology and structure of the HMX-based composites were characterized in detail and the core-shell structure was validated.The grafted polymers obviously enhanced the adhesion force between HMX crystals and fluoropolymer(F2314)binder.Due to the interfacial reinforcement among the components,the two HMX-based composites exhibited a remarkable increment of phase transition peak temperature by 10.2°C and 19.6°C with no more than 1.5%shell content,respectively.Furthermore,the impact and friction sensitivity of the composites decreased significantly as a result of the barrier produced by the grafted polymers.These findings will enhance the future prospects for the interface design of energetic composites aiming to solve the weak interface and safety concerns. 展开更多
关键词 HMX crystals Polyalcohol bonding agent Energetic polymer core-shell structure Interfacial reinforcement
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Core-shell mesoporous carbon hollow spheres as Se hosts for advanced Al-Se batteries
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作者 Haiping Lei Tianwei Wei +1 位作者 Jiguo Tu Shuqiang Jiao 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第5期899-906,共8页
Incorporating a selenium(Se)positive electrode into aluminum(Al)-ion batteries is an effective strategy for improving the overall battery performance.However,the cycling stability of Se positive electrodes has challen... Incorporating a selenium(Se)positive electrode into aluminum(Al)-ion batteries is an effective strategy for improving the overall battery performance.However,the cycling stability of Se positive electrodes has challenges due to the dissolution of intermediate reaction products.In this work,we aim to harness the advantages of Se while reducing its limitations by preparing a core-shell mesoporous carbon hollow sphere with a titanium nitride(C@TiN)host to load 63.9wt%Se as the positive electrode material for Al-Se batteries.Using the physical and chemical confinement offered by the hollow mesoporous carbon and TiN,the obtained core-shell mesoporous carbon hollow spheres coated with Se(Se@C@TiN)display superior utilization of the active material and remarkable cycling stability.As a result,Al-Se batteries equipped with the as-prepared Se@C@TiN composite positive electrodes show an initial discharge specific capacity of 377 mAh·g^(-1)at a current density of 1000 mA·g^(-1)while maintaining a discharge specific capacity of 86.0 mAh·g^(-1)over 200 cycles.This improved cycling performance is ascribed to the high electrical conductivity of the core-shell mesoporous carbon hollow spheres and the unique three-dimensional hierarchical architecture of Se@C@TiN. 展开更多
关键词 aluminum-selenium batteries intermediate products core-shell mesoporous carbon hollow sphere cycling performance
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Fe-N_(x) sites coupled with core-shell FeS@C nanoparticles to boost the oxygen catalysis for rechargeable Zn-air batteries
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作者 Katam Srinivas Zhuo Chen +3 位作者 Anran Chen Fei Ma Ming-qiang Zhu Yuanfu Chen 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第3期565-577,I0013,共14页
The development of efficient single-atom catalysts(SACs) for the oxygen reduction reaction(ORR)remains a formidable challenge,primarily due to the symmetric charge distribution of metal singleatom sites(M-N_(4)).To ad... The development of efficient single-atom catalysts(SACs) for the oxygen reduction reaction(ORR)remains a formidable challenge,primarily due to the symmetric charge distribution of metal singleatom sites(M-N_(4)).To address such issue,herein,Fe-N_(x) sites coupled synergistic catalysts fabrication strategy is presented to break the uniform electronic distribution,thus enhancing the intrinsic catalytic activity.Precisely,atomically dispersed Fe-N_(x) sites supported on N/S-doped mesoporous carbon(NSC)coupled with FeS@C core-shell nanoparticles(FAS-NSC@950) is synthesized by a facile hydrothermal reaction and subsequent pyrolysis.Due to the presence of an in situ-grown conductive graphitic layer(shell),the FeS nanoparticles(core) effectively adjust the electronic structure of single-atom Fe sites and facilitate the ORR kinetics via short/long-range coupling interactions.Consequently,FAS-NSC@950displays a more positive half-wave potential(E_(1/2)) of 0.871 V with a significantly boosted ORR kinetics(Tafel slope=52.2 mV dec^(-1)),outpacing the commercial Pt/C(E_(1/2)=0.84 V and Tafel slope=54.6 mV dec^(-1)).As a bifunctional electrocatalyst,it displays a smaller bifunctional activity parameter(ΔE) of 0.673 V,surpassing the Pt/C-RuO_(2) combination(ΔE=0.724 V).Besides,the FAS-NSC@950-based zincair battery(ZAB) displays superior power density,specific capacity,and long-term cycling performance to the Pt/C-Ir/C-based ZAB.This work significantly contributes to the field by offering a promising strategy to enhance the catalytic activity of SACs for ORR,with potential implications for energy conversion and storage technologies. 展开更多
关键词 Fe-N_(x)sites core-shell FeS@C Synergistic interactions Oxygen reduction reaction Zn-air battery
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Synergistic Tuning of Nickel Cobalt Selenide@Nickel Telluride Core-Shell Heteroarchitectures for Boosting Overall Urea Electrooxidation and Electrochemical Supercapattery
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作者 Diab Khalafallah Weibo Huang +1 位作者 Mingjia Zhi Zhanglian Hong 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2024年第1期301-312,共12页
Herein,we demonstrate the synthesis of bifunctional nickel cobalt selenide@nickel telluride(Ni_(x)Co_(12-x)Se@NiTe)core-shell heterostructures via an electrodeposition approach for overall urea electrolysis and superc... Herein,we demonstrate the synthesis of bifunctional nickel cobalt selenide@nickel telluride(Ni_(x)Co_(12-x)Se@NiTe)core-shell heterostructures via an electrodeposition approach for overall urea electrolysis and supercapacitors.The 3D vertically orientated NiTe dendritic frameworks induce the homogeneous nucleation of 2D Ni_(x)Co_(12-x)Se nanosheet arrays along similar crystal directions and bring a strong interfacial binding between the integrated active components.In particular,the optimized Ni_(6)Co_(6)Se@NiTe with an interface coupling effect works in concert to tune the intrinsic activity.It only needs a low overpotential of 1.33 V to yield a current density of 10 mA cm^(-2)for alkaline urea electrolysis.Meanwhile,the full urea catalysis driven only by Ni_(6)Co_(6)Se@NiTe achieves 10 mA cm^(-2)at a potential of 1.38 V and can approach a constant level of the current response for 40 h.Besides,the integrated Ni_(6)Co_(6)Se@NiTe electrode delivers an enhanced specific capacity(223 mA h g^(-1)at 1 A g^(-1))with a high cycling stability.Consequently,a hybrid asymmetric supercapacitor(HASC)device based on Ni_(6)Co_(6)Se@NiTe exhibits a favorable rate capability and reaches a high energy density of 67.7 Wh kg^(-1)and a power density of 724.8 W kg^(-1)with an exceptional capacity retention of 92.4%after sequential 12000 cycles at 5 A g^(-1). 展开更多
关键词 bifunctional Ni_(x)Co_(12-x)Se@NiTe core-shell electrodeposition heterointerfaces supercapacitors UOR
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Fabrication of Core-Shell Hydrogel Bead Based on Sodium Alginate and Chitosan for Methylene Blue Adsorption
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作者 Xiaoyu Chen 《Journal of Renewable Materials》 EI CAS 2024年第4期815-826,共12页
A novel core-shell hydrogel bead was fabricated for effective removal of methylene blue dye from aqueous solutions.The core,made of sodium alginate-g-polyacrylamide and attapulgite nanofibers,was cross-linked by Calci... A novel core-shell hydrogel bead was fabricated for effective removal of methylene blue dye from aqueous solutions.The core,made of sodium alginate-g-polyacrylamide and attapulgite nanofibers,was cross-linked by Calcium ions(Ca^(2+)).The shell,composed of a chitosan/activated carbon mixture,was then coated onto the core.Fourier transform infrared spectroscopy confirmed the grafting polymerization of acrylamide onto sodium alginate.Scanning electron microscopy images showed the core-shell structure.The core exhibited a high water uptake ratio,facilitating the diffusion of methylene blue into the core.During the diffusion process,the methylene blue was first adsorbed by the shell and then further adsorbed by the core.Adsorption tests showed that the coreshell structure had a larger adsorption capacity than the core alone.The shell effectively enhanced the adsorption capacity to methylene blue compared to the single core.Methylene blue was adsorbed by activated carbon and chitosan in the shell,and the residual methylene blue diffused into the core and was further adsorbed. 展开更多
关键词 core-shell structure hydrogel bead attapulgite nanofiber sodium alginate POLYACRYLAMIDE methylene blue adsorption material
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Magnetic core-shell microparticles for oil removing with thermal driving regeneration property 被引量:1
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作者 Shi-Hao Chen Chuan-Lin Mou +3 位作者 Wen-Long Ma Ya-Dong Li Zi-Yu Tang Hong-Bo Deng 《Petroleum Science》 SCIE EI CAS CSCD 2023年第4期2531-2544,共14页
Here, we report the construction of magnetic core-shell microparticles for oil removal with thermal driving regeneration property. Water-in-oil-in water (W/O/W) emulsions from microfluidics are used as templates to pr... Here, we report the construction of magnetic core-shell microparticles for oil removal with thermal driving regeneration property. Water-in-oil-in water (W/O/W) emulsions from microfluidics are used as templates to prepare core-shell microparticles with magnetic holed poly (ethoxylated trimethylolpropane triacrylate) (PETPTA) shells each containing a thermal-sensitive poly (N-Isopropylacrylamide) (PNIPAM) core. The microparticles could adsorb oil from water due to the special structure and be collected with a magnetic field. Then, the oil-filled microparticles would be regenerated by thermal stimulus, in which the inner PNIPAM microgels work as thermal-sensitive pistons to force out the adsorbed oil. At the same time, the adsorbed oil would be recycled by distillation. Furthermore, the adsorption capacity of the microparticles for oil keeps very stable after 1st cycle. The adsorption and regeneration performances of the microparticles are greatly affected by the size of the holes on the outer PETPTA shells, which could be precisely controlled by regulating the interfacial forces in W/O/W emulsion templates. The optimized core-shell microparticles show excellent oil adsorption and thermal driving regeneration performances nearly without secondary pollution, and would be a reliable green adsorption material for kinds of oil. 展开更多
关键词 MICROFLUIDICS core-shell microparticles Thermal driving regeneration Secondary pollution Oil adsorption
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Surface treatment effect on the photocatalytic hydrogen generation of CdS/ZnS core-shell microstructures 被引量:7
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作者 苏进展 张涛 +2 位作者 王璐 师进文 陈玉彬 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2017年第3期489-497,共9页
CdS/ZnS core-shell microparticles were prepared by a simple two-step method combining ultrasonic spray pyrolysis and chemical bath deposition.The core-shell structures showed enhanced photocatalytic properties compare... CdS/ZnS core-shell microparticles were prepared by a simple two-step method combining ultrasonic spray pyrolysis and chemical bath deposition.The core-shell structures showed enhanced photocatalytic properties compared with those of CdS or ZnS spherical particles.CdS/ZnS photocatalysts with different amount of ZnS loaded as shells were prepared by adjusting the concentrations of Zn and S precursors during synthesis.The optical properties and photocatalytic activity for hydrogen production were investigated and the amount of ZnS loaded as shell was optimized.Thermal annealing and hydrothermal sulfurization treatments were applied to the core-shell structure and both treatments enhanced the material's photocatalytic activity and stability by eliminating crystalline defects and surface states.The result showed that thermal annealing treatment improved the bulk crystallinity and hydrothermal sulfurization improved the surface properties.The sample subjected to both treatments showed the highest photocatalytic activity.These results indicate that CdS/ZnS core-shell microspheres are a simple structure that can be used as efficient photocatalysts.The hydrothermal sulfurization treatment may also be a useful surface treatment for metal sulfide photocatalysts.The simple two-step method provides a promising approach to the large-scale synthesis of core-shell microsphere catalysts. 展开更多
关键词 core-shell microstructure PHOTOCATALYSIS Surface treatment Hydrogen production Low-cost synthesis
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Preparation and characterization of ZnSe/CdSe core-shell microspheres
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作者 段雨露 周丽旗 +3 位作者 徐国富 张慧颖 李旭 刘小鹤 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第5期1559-1567,共9页
The preparation of Zn Se/Cd Se core-shell structure nanocomposites by using the re-prepared Zn Se microspheres as the template under the hydrothermal condition was presented. The influence of different mole ratios of ... The preparation of Zn Se/Cd Se core-shell structure nanocomposites by using the re-prepared Zn Se microspheres as the template under the hydrothermal condition was presented. The influence of different mole ratios of ZnS e to Cd(NO3)2 on the morphology and structure of the final product was investigated. And the performances of ZnS e/Cd Se core-shell structure nanocomposites were characterized by the means of X-ray diffraction(XRD) analyses, scanning electron microscopy(SEM), transmission electron microscopy(TEM) and photoluminescence(PL) spectroscopy. The results indicate that the core-shell structure product can be prepared, when the mole ratio of Zn Se to Cd(NO3)2 is larger than 1:1; and the product will be ball solid structure, when the mole ratio of Zn Se to Cd(NO3)2 is equal to 1:1. The photo luminescence results show that Zn Se/Cd Se core-shell structures have high photo luminescence emission properties, and the product with mole ratio of Zn Se to Cd(NO3)2 being 1:0.5 has the best luminescence properties. 展开更多
关键词 hydrothermal methed core-shell nanocomposite ZNSE CDSE optical property
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基于改进Ratio统计量的重尾AR(p)时间序列均值变点检验
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作者 张思 刘叶 金浩 《统计与决策》 北大核心 2024年第2期52-57,共6页
文章提出两个改进的Ratio统计量来研究重尾AR(p)时间序列均值变点检验问题,在原假设下推导了统计量的渐近分布,且在备择假设下证明了其一致性。由于重尾指数未知且难以估计,因此结合Wild Bootstrap重抽样方法来确定渐近分布的临界值;在... 文章提出两个改进的Ratio统计量来研究重尾AR(p)时间序列均值变点检验问题,在原假设下推导了统计量的渐近分布,且在备择假设下证明了其一致性。由于重尾指数未知且难以估计,因此结合Wild Bootstrap重抽样方法来确定渐近分布的临界值;在均值变点存在的情形下,给出了变点位置的一致估计量。数值模拟结果表明:统计量的临界值均不受重尾指数和自回归系数的影响,其经验水平和经验势均取得满意的效果;尤其在原假设下,积分型Ratio统计量的经验水平表现出更好的稳健性,而在备择假设下,最值型Ratio统计量则具备更好的显著性。最后,基于一组股票数据,从实际应用角度进一步阐明所提方法的有效性和可行性。 展开更多
关键词 重尾序列 ratio统计量 均值变点 Wild Bootstrap
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Efficient microwave absorption achieved through in situ construction of core-shell Co Fe_(2)O_(4)@mesoporous carbon hollow spheres 被引量:11
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作者 Lianggui Ren Yiqun Wang +2 位作者 Xin Zhang Qinchuan He Guanglei Wu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2023年第3期504-514,共11页
Cobalt ferrite(CoFe_(2)O_(4)),with good chemical stability and magnetic loss,can be used to prepare composites with a unique structure and high absorption.In this study,CoFe_(2)O_(4)@mesoporous carbon hollow spheres(M... Cobalt ferrite(CoFe_(2)O_(4)),with good chemical stability and magnetic loss,can be used to prepare composites with a unique structure and high absorption.In this study,CoFe_(2)O_(4)@mesoporous carbon hollow spheres(MCHS)with a core-shell structure were prepared by introducing CoFe_(2)O_(4)magnetic particles into hollow mesoporous carbon through a simple in situ method.Then,the microwave absorption performance of the CoFe_(2)O_(4)@MCHS composites was investigated.Magnetic and dielectric losses can be effectively coordinated by constructing the porous structure and adjusting the ratio of MCHS and CoFe_(2)O_(4).Results show that the impedance matching and absorption properties of the Co Fe_(2)O_(4)@MCHS composites can be altered by tweaking the mass ratio of MCHS and CoFe_(2)O_(4).The minimum reflection loss of the Co Fe_(2)O_(4)@MCHS composites reaches-29.7 dB at 5.8 GHz.In addition,the effective absorption bandwidth is 3.7 GHz,with the thickness being 2.5 mm.The boosted microwave absorption can be ascribed to the porous core-shell structure and introduction of magnetic particles.The coordination between the microporous morphology and the core-shell structure is conducive to improving the attenuation coefficient and achieving good impedance matching.The porous core-shell structure provides large solid-void and CoFe_(2)O_(4)-C interfaces to induce interfacial polarization and extend the electromagnetic waves’multiple scattering and reflection.Furthermore,natural resonance,exchange resonance,and eddy current loss work together for the magnetic loss.This method provides a practical solution to prepare core-shell structure microwave absorbents. 展开更多
关键词 porous core-shell structure microwave absorption interface polarization FERRITE structure-controllable
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Template-free synthesis of core-shell Fe_(3)O_(4)@MoS_(2)@mesoporous TiO_(2) magnetic photocatalyst for wastewater treatment 被引量:4
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作者 Jingshu Yuan Yao Zhang +3 位作者 Xiaoyan Zhang Liang Zhao Hanlin Shen Shengen Zhang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2023年第1期177-191,共15页
TiO_(2)is the dominant and most widely researched photocatalyst for environmental remediation,however,the drawbacks,such as only responding to UV light(<5%of sunlight),low charge separation efficiency,and difficult... TiO_(2)is the dominant and most widely researched photocatalyst for environmental remediation,however,the drawbacks,such as only responding to UV light(<5%of sunlight),low charge separation efficiency,and difficulties in recycling,have severely hindered its practical application.Herein,we synthesized magnetically separable Fe_(3)O_(4)@MoS_(2)@mesoporous TiO_(2)(FMmT)photocatalysts via a simple,green,and template-free solvothermal method combined with ultrasonic hydrolysis.It is found that FMmT possesses a high specific surface area(55.09 m2·g−1),enhanced visible-light responsiveness(~521 nm),and remarkable photogenerated charge separation efficiency.In addition,the photocatalytic degradation efficiencies of FMmT for methylene blue(MB),rhodamine B(RhB),and tetracycline(TC)are 99.4%,98.5%,and 89.3%within 300 min,respectively.The corresponding degradation rates are 4.5,4.3,and 3.1 times higher than those of pure TiO_(2)separately.Owing to the high saturation magnetization(43.1 A·m^(2)·kg^(−1)),FMmT can achieve effective recycling with an applied magnetic field.The improved photocatalytic activity is closely related to the effective transport of photogenerated electrons by the active interlayer MoS_(2) and the electron–hole separation caused by the MoS_(2)@TiO_(2)heterojunction.Meanwhile,the excellent light-harvesting ability and abundant reactive sites of the mesoporous TiO_(2)shell further boost the photocatalytic efficiency of FMmT.This work provides a new approach and some experimental basis for the design and performance improvement of magnetic photocatalysts by innovatively incorporating MoS2 as the active interlayer and integrating it with a mesoporous shell. 展开更多
关键词 core-shell MoS2 mesoporous TiO2 photocatalytic degradation heterojunction magnetic recycling
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Engineering hollow core-shell hetero-structure box to induce interfacial charge modulation for promoting bidirectional sulfur conversion in lithium-sulfur batteries 被引量:3
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作者 Weiliang Zhou Xinying Wang +5 位作者 Jiongwei Shan Liguo Yue Dongzhen Lu Li Chen Jiacheng Zhang Yunyong Li 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第5期128-139,I0004,共13页
Severe polysulfide shuttling and sluggish sulfur redox kinetics significantly decrease sulfur utilization and cycling stability in lithium-sulfur batteries(LSBs).Herein,we develop a hollow CoO/CoP-Box core-shell heter... Severe polysulfide shuttling and sluggish sulfur redox kinetics significantly decrease sulfur utilization and cycling stability in lithium-sulfur batteries(LSBs).Herein,we develop a hollow CoO/CoP-Box core-shell heterostructure as a model and multifunctional catalyst modified on separators to induce interfacial charge modulation and expose more active sites for promoting the adsorption and catalytic conversion ability of sulfur species.Theoretical and experimental findings verify that the in-situ formed core-shell hetero-interface induces the formation of P-Co-O binding and charge redistribution to activate surface O active sites for binding lithium polysulfides(LiPSs)via strong Li-O bonding,thus strongly adsorbing with Li PSs.Meanwhile,the strong Li-O bonding weakens the competing Li-S bonding in LiPSs or Li2S adsorbed on CoO/CoP-Box surface,plus the hollow heterostructure provides abundant active sites and fast electron/Li+transfer,so reducing Li2S nucleation/dissolution activation energy.As expected,LSBs with CoO/CoP-Box modified separator and traditional sulfur/carbon black cathode display a large initial capacity of 1240 mA h g^(-1)and a long cycling stability with 300 cycles(~60.1%capacity retention)at 0.5C.Impressively,the thick sulfur cathode(sulfur loading:5.2 mg cm^(-2))displays a high initial areal capacity of 6.9 mA h cm^(-2).This work verifies a deep mechanism understanding and an effective strategy to induce interfacial charge modulation and enhance active sites for designing efficient dual-directional Li-S catalysts via engineering hollow core-shell hetero-structure. 展开更多
关键词 CoO/CoP-Box Hollow core-shell hetero-structure Multifunctional catalysts Interfacial charge modulation Lithium sulfur batteries
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Rapid Analysis of Four Alkaloids in Uncaria rhynchophylla by Core-Shell Column HPLC and Quantitative Analysis of Multi-Components by Single Marker(QAMS) 被引量:1
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作者 Kesheng Lin Jiawen Zhou +1 位作者 Lijuan Han Ning Li 《Phyton-International Journal of Experimental Botany》 SCIE 2023年第1期285-296,共12页
As a traditional herbal medicine,the major alkaloids in Uncaria rhynchophylla have been proven to have blood pressure-lowering and sedative effects.It is essential to develop an effective method for the determination ... As a traditional herbal medicine,the major alkaloids in Uncaria rhynchophylla have been proven to have blood pressure-lowering and sedative effects.It is essential to develop an effective method for the determination of the major alkaloids in U.rhynchophylla.In this research,a rapid quantitative analysis involving multi-components analysis by a single marker strategy coupled with core-shell column HPLC was adopted to analyse four alkaloids(corynoxeine,isocorynoxeine,isorhynchophylline,rhynchophylline)in U.rhynchophylla.Isorhynchophylline was selected as the internal reference substance,the content of which was determined by the traditional external standard method.Relative correction factors(RCF)between isorhynchophylline and the other three alkaloids were calculated respectively.The results showed that the QAMS method had good robustness under different HPLC instruments.Nineteen batches of U.rhynchophylla were tested.No significant difference was observed between the results by QAMS and EMS(Correlation coefficient>0.99,p>0.05).The QAMS method could be employed as a rapid,effective technique for the quality control of U.rhynchophylla. 展开更多
关键词 Uncaria rhynchophylla HPLC core-shell column QAMS
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Carbon nanotube-hyperbranched polymer core-shell nanowires with highly accessible redox-active sites for fast-charge organic lithium batteries 被引量:1
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作者 Zhonghui Sun Meng Shu +4 位作者 Jiabin Li Bing Liu Hongyan Yao Shaowei Guan Zhenhua Sun 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第3期30-36,I0002,共8页
Organic electrode materials are promising for lithium-ion batteries(LIBs) because of their environmental friendliness and structural diversity.However,they always suffer from limited capacity,poor cycling stability,an... Organic electrode materials are promising for lithium-ion batteries(LIBs) because of their environmental friendliness and structural diversity.However,they always suffer from limited capacity,poor cycling stability,and rate performance.Herein,hexaazatrinaphthalene-based azo-linked hyperbranched polymer(HAHP) is designed and synthesized as a cathode for LIBs.However,the densely stacked morphology lowers the chance of the active sites participating in the redox reaction.To address this issue,the singlewalled carbon nanotube(SWCNT) template is used to induce the growth of nanosized HAHP on the surface of SWCNTs.The HAHP@SWCNT nanocomposites have porous structures and highly accessible active sites.Moreover,the strong π-π interaction between HAHP and highly conductive SWCNTs effectively endows the HAHP@SWCNT nanocomposites with improved cycling stability and fast charge-discharge rates.As a result,the HAHP@SWCNT nanocomposite cathode shows a high specific capacity(320.4 mA h g^(-1)at 100 mA g^(-1)),excellent cycling stability(800 cycles;290 mA h g^(-1)at 100 mA g^(-1),capacity retained 91%) and outstanding rate performance(235 mA h g^(-1)at 2000 mA g^(-1),76% capacity retention versus 50 mA g^(-1)).This work provides a strategy to combine the macromolecular structural design and micromorphology control of electrode materials for obtaining organic polymer cathodes for high-performance LIBs. 展开更多
关键词 Organic electrode Organic lithium batteries core-shell nanowire Hexaazatrinaphthylene Polymer electrode materials
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