The high activity and stability of intermetallic PtCo nanocatalysts toward oxygen reduction reaction make them a top candidate as low-Pt cathode catalysts in proton exchange membrane fuel cells(PEMFCs).However,forming...The high activity and stability of intermetallic PtCo nanocatalysts toward oxygen reduction reaction make them a top candidate as low-Pt cathode catalysts in proton exchange membrane fuel cells(PEMFCs).However,forming intermetallic structures typically requires high-temperature annealing,posing a challenge for achieving well-size control and highly ordered structures.Here we report the design and synthesis of bimetallic co re@shell structured precursors for affording high-performance intermetallic PtCo catalysts.The fabrication of the core@shell precursor involves using a molecular ligand containing both sulfur and oxygen donors to selectively bind with Pt colloidal nanoparticles as the core and chelate Co ions as the shell.During high-temperature annealing,the ligand transforms into carbon coatings around alloy nanoparticles,preventing particle sintering;meanwhile,Co ions in the shell can easily diffuse into the Pt core,which helps to increase the thermodynamic driving force for forming intermetallic structures.These benefits enable us to obtain the catalyst with finely dispersed nanoparticles(~3.5 nm)and a high ordering degree of 72%.With 0.1 mgPt/cm^(2)cathode loading,the catalyst delivers superior performance and durability in PEMFCs,showing an initial mass activity of 0.56 A/mgPt,an initial power density of 1.05 W/cm^(2)at 0.67 V(H_(2)-air),and a voltage loss of 26 mV at 0.8 A/cm^(2)after the accelerated durability test.展开更多
Increasing both clean water and green energy demands for survival and development are the grand challenges of our age.Here,we successfully fabricate a novel multifunctional 3D graphene-based catalytic membrane(3D-GCM)...Increasing both clean water and green energy demands for survival and development are the grand challenges of our age.Here,we successfully fabricate a novel multifunctional 3D graphene-based catalytic membrane(3D-GCM)with active metal nanoparticles(AMNs)loading for simultaneously obtaining the water purification and clean energy generation,via a“green”one-step laser scribing technology.The as-prepared 3D-GCM shows high porosity and uniform distribution with AMNs,which exhibits high permeated fluxes(over 100 L m^(−2) h^(−1))and versatile super-adsorption capacities for the removal of tricky organic pollutants from wastewater under ultra-low pressure-driving(0.1 bar).After adsorption saturating,the AMNs in 3D-GCM actuates the advanced oxidization process to self-clean the fouled membrane via the catalysis,and restores the adsorption capacity well for the next time membrane separation.Most importantly,the 3D-GCM with the welding of laser scribing overcomes the lateral shear force damaging during the long-term separation.Moreover,the 3D-GCM could emit plentiful of hot electrons from AMNs under light irradiation,realizing the membrane catalytic hydrolysis reactions for hydrogen energy generation.This“green”precision manufacturing with laser scribing technology provides a feasible technology to fabricate high-efficient and robust 3D-GCM microreactor in the tricky wastewater purification and sustainable clean energy production as well.展开更多
低地球轨道(Low Earth Orbit,LEO)卫星无源定位场景中不同目标辐射源之间相互干扰、时频混叠,不同目标的到达时差(Time Difference Of Arrival,TDOA)参数混杂难以区分,较难实现精准目标定位。基于网格密度聚类算法(Clustering Algorithm...低地球轨道(Low Earth Orbit,LEO)卫星无源定位场景中不同目标辐射源之间相互干扰、时频混叠,不同目标的到达时差(Time Difference Of Arrival,TDOA)参数混杂难以区分,较难实现精准目标定位。基于网格密度聚类算法(Clustering Algorithm based on Grid Density,CAGD)的基本原理,并利用TDOA参数的多复杂特征,构建多目标TDOA参数分选模型,实现TDOA定位参数分选。模型通过定义网格密度波谷,解决了定位目标间数据被聚为一类的问题,同时引入位置相连原则实现最佳类簇合并,最终实现定位参数分选。仿真结果表明,相较于传统网格及密度聚类方法,本方法对LEO卫星无源定位场景下的多目标TDOA参数分选表现更好。展开更多
Two-dimensional(2D) materials, such as graphene, transition metal dichalcogenides(TMDs), black phosphorus(BP),and related derivatives, have attracted great attention due to their advantages of flexibility, strong ligh...Two-dimensional(2D) materials, such as graphene, transition metal dichalcogenides(TMDs), black phosphorus(BP),and related derivatives, have attracted great attention due to their advantages of flexibility, strong light–matter interaction,broadband absorption, and high carrier mobility, and have become a powerful contender for next-generation infrared photodetectors. However, since the thickness of 2D materials is on the order of nanometers, the absorption of 2D materials is very weak, which limits the detection performance of 2D materials-based infrared photodetectors. In order to solve this problem, scientific researchers have tried to use optimized device structures to combine with 2D materials for improving the performance of infrared photodetectors. In this review, we review the progress of room-temperature infrared photodetectors with hybrid structure based on 2D materials in recent years, focusing mainly on 2D–nD(n = 0, 1, 2) heterostructures, the integration between 2D materials and on-chip or plasmonic structure. Finally, we summarize the current challenges and point out the future development direction.展开更多
基金the funding support from the National Natural Science Foundation of China(Grants 22325903,22221003,and 22071225)the National Key Research and Development Program of China(Grant 2018YFA0702001)+1 种基金the Plan for Anhui Major Provincial Science&Technology Project(Grants 202203a0520013 and 2021d05050006)the USTC Research Funds of the Double First-Class Initiative(Grant YD2060002032).
文摘The high activity and stability of intermetallic PtCo nanocatalysts toward oxygen reduction reaction make them a top candidate as low-Pt cathode catalysts in proton exchange membrane fuel cells(PEMFCs).However,forming intermetallic structures typically requires high-temperature annealing,posing a challenge for achieving well-size control and highly ordered structures.Here we report the design and synthesis of bimetallic co re@shell structured precursors for affording high-performance intermetallic PtCo catalysts.The fabrication of the core@shell precursor involves using a molecular ligand containing both sulfur and oxygen donors to selectively bind with Pt colloidal nanoparticles as the core and chelate Co ions as the shell.During high-temperature annealing,the ligand transforms into carbon coatings around alloy nanoparticles,preventing particle sintering;meanwhile,Co ions in the shell can easily diffuse into the Pt core,which helps to increase the thermodynamic driving force for forming intermetallic structures.These benefits enable us to obtain the catalyst with finely dispersed nanoparticles(~3.5 nm)and a high ordering degree of 72%.With 0.1 mgPt/cm^(2)cathode loading,the catalyst delivers superior performance and durability in PEMFCs,showing an initial mass activity of 0.56 A/mgPt,an initial power density of 1.05 W/cm^(2)at 0.67 V(H_(2)-air),and a voltage loss of 26 mV at 0.8 A/cm^(2)after the accelerated durability test.
基金supported by the National Scientific Foundation of China(No.61974050,61704061,51805184,61974049)Key Laboratory of Non-ferrous Metals and New Materials Processing Technology of Ministry of Education/Guangxi Key Laboratory of Optoelectronic Materials and Devices open Fund(20KF-9)+2 种基金the Natural Science Foundation of Hunan Province of China(No.2018TP2003)Excellent youth project of Hunan Provincial Department of Education(No.18B111)State Key Laboratory of Crop Germplasm Innovation and Resource Utilization(No.17KFXN02).The authors thank the technical support from Analytical and Testing Center at Huazhong University of Science and Technology.
文摘Increasing both clean water and green energy demands for survival and development are the grand challenges of our age.Here,we successfully fabricate a novel multifunctional 3D graphene-based catalytic membrane(3D-GCM)with active metal nanoparticles(AMNs)loading for simultaneously obtaining the water purification and clean energy generation,via a“green”one-step laser scribing technology.The as-prepared 3D-GCM shows high porosity and uniform distribution with AMNs,which exhibits high permeated fluxes(over 100 L m^(−2) h^(−1))and versatile super-adsorption capacities for the removal of tricky organic pollutants from wastewater under ultra-low pressure-driving(0.1 bar).After adsorption saturating,the AMNs in 3D-GCM actuates the advanced oxidization process to self-clean the fouled membrane via the catalysis,and restores the adsorption capacity well for the next time membrane separation.Most importantly,the 3D-GCM with the welding of laser scribing overcomes the lateral shear force damaging during the long-term separation.Moreover,the 3D-GCM could emit plentiful of hot electrons from AMNs under light irradiation,realizing the membrane catalytic hydrolysis reactions for hydrogen energy generation.This“green”precision manufacturing with laser scribing technology provides a feasible technology to fabricate high-efficient and robust 3D-GCM microreactor in the tricky wastewater purification and sustainable clean energy production as well.
文摘低地球轨道(Low Earth Orbit,LEO)卫星无源定位场景中不同目标辐射源之间相互干扰、时频混叠,不同目标的到达时差(Time Difference Of Arrival,TDOA)参数混杂难以区分,较难实现精准目标定位。基于网格密度聚类算法(Clustering Algorithm based on Grid Density,CAGD)的基本原理,并利用TDOA参数的多复杂特征,构建多目标TDOA参数分选模型,实现TDOA定位参数分选。模型通过定义网格密度波谷,解决了定位目标间数据被聚为一类的问题,同时引入位置相连原则实现最佳类簇合并,最终实现定位参数分选。仿真结果表明,相较于传统网格及密度聚类方法,本方法对LEO卫星无源定位场景下的多目标TDOA参数分选表现更好。
基金Project supported by the National Natural Science Foundation of China(Grant No.61704061)
文摘Two-dimensional(2D) materials, such as graphene, transition metal dichalcogenides(TMDs), black phosphorus(BP),and related derivatives, have attracted great attention due to their advantages of flexibility, strong light–matter interaction,broadband absorption, and high carrier mobility, and have become a powerful contender for next-generation infrared photodetectors. However, since the thickness of 2D materials is on the order of nanometers, the absorption of 2D materials is very weak, which limits the detection performance of 2D materials-based infrared photodetectors. In order to solve this problem, scientific researchers have tried to use optimized device structures to combine with 2D materials for improving the performance of infrared photodetectors. In this review, we review the progress of room-temperature infrared photodetectors with hybrid structure based on 2D materials in recent years, focusing mainly on 2D–nD(n = 0, 1, 2) heterostructures, the integration between 2D materials and on-chip or plasmonic structure. Finally, we summarize the current challenges and point out the future development direction.
