Graphitic carbon nitride(g-C_(3)N_(4))with the merits of high visible light absorption,proper electronic band structure with high conduction band edge and variable modulation,is viewed as a promising photocatalyst for...Graphitic carbon nitride(g-C_(3)N_(4))with the merits of high visible light absorption,proper electronic band structure with high conduction band edge and variable modulation,is viewed as a promising photocatalyst for practical use.To alleviate its high recombination rate of photo-excited charge carriers and maximize the photocatalytic performances,it is paramount to design highly effective transfer channels for photo-excited charge carriers.Ferroelectric materials can have the charge carriers transport in opposite directions owing to the internal spontaneous polarization,which may be suitable for constructing the heterostructure with g-C_(3)N_(4)for efficient charge separation.Inspired by this concept,herein ferroelectric PbTiO_(3),which can be the visible-light absorber,is coupled with g-C_(3)N_(4)to construct PbTiO_(3)/g-C_(3)N_(4)heterostructure with close contact via Pb–N bond by the facile post thermal treatment.The optimized Pb TiO_(3)/g-C_(3)N_(4)heterostructure exhibited excellent photocatalytic and photoelectrochemical activities under visible light irradiation.Moreover,the simultaneous application of ultrasound-induced mechanical waves can further improve its photocatalytic activities through reinforcing the built-in piezoelectric field.This work proposes a widely applicable strategy for the fabrication of high-performance ferroelectric based photocatalysts and also provides some new ideas for developing the understanding of ferroelectric photocatalysis.展开更多
To acquire efficient photocatalysts,it is necessary to make effective use of visible light/Near Infrared(NIR)light,which takes up a large percentage of sunlight.Integrating upconversion materials with visible light ac...To acquire efficient photocatalysts,it is necessary to make effective use of visible light/Near Infrared(NIR)light,which takes up a large percentage of sunlight.Integrating upconversion materials with visible light active photocatalysts has attracted much attention in this regard.The interface contact between upcon-version material and photocatalyst has potential influence on the properties and thus the performance of the system.In this work,NaYF_(4):Yb,Er/CdS composites of the upconversion material NaYF_(4):Yb,Er nanorods and CdS nanoparticles were synthesized by ion adsorption/precipitation process and were then annealed in an argon atmosphere at different temperatures to modulate the microstructures.The annealing pro-cess endows the crystal transformation of cubic CdS with low crystallinity to hexagonal CdS with high crystallinity and,importantly,good interface contact between NaYF_(4):Yb,Er and CdS.Consequently,the hy-drogen evolution activity greatly increases from 171 to 2539μmol h^(−1) g^(−1) under the light irradiation ofλ>400 nm,and from 0 to 19μmol h^(−1) g^(−1) under the light irradiation ofλ>600 nm.This work might provide a useful reference for the rational design of promising photocatalyst involving upconversion ma-terials.展开更多
Graphitic carbon nitride(g-C_(3)N_(4))is viewed as a promising visible-light photocatalyst for industrialization due to its low processing temperature and high chemical stability.However,serious charge recombination c...Graphitic carbon nitride(g-C_(3)N_(4))is viewed as a promising visible-light photocatalyst for industrialization due to its low processing temperature and high chemical stability.However,serious charge recombination caused by incomplete polymerization during direct calcination of nitrogen-rich precursors significantly limits its photocatalytic performances.To boost charge separation,herein,we propose a rational strategy by constructing a crystalline g-C_(3)N_(4)/g-C_(3)N_(4-x)S_(x) isotype heterostructure through the molten salt method.Theoretical calculation reveals that apparent charge-transfer channels are formed between g-C_(3)N_(4) and S-doped g-C_(3)N_(4) layers in the heterostructure.Owing to high crystallinity for decreasing charge recombination and isotype heterostructure for efficient charge transfer,the as-prepared g-C_(3)N_(4)/g-C_(3)N_(4-x)S_(x) showed remarkable photocatalytic performances with the hydrogen production rate elevated by up to 12.3 times of its singular components.Another novelty of this work is we investigated for the first time the piezocatalytic activity of crystalline g-C_(3)N_(4) by characterizing its performance for H2O2 generation and KMnO4 reduction.Strikingly,its superior piezocatalytic performance over components can be further improved by NaBH4 treatment,which is uncovered to enhance the asymmetric structure of crystalline g-C_(3)N_(4) by introducing extra cyano groups and removing partial NHx species in its tri-s-triazine layer structure.This work opens up new strategies for the design of highly efficient polymeric photocatalysts and highlights the piezocatalytic studies of g-C_(3)N_(4).展开更多
Carbon nitrides with two-dimensional layered structures and high theoretical capacities are attractive as anode materials for sodium-ion batteries while their low crystallinity and insufficient structural stability st...Carbon nitrides with two-dimensional layered structures and high theoretical capacities are attractive as anode materials for sodium-ion batteries while their low crystallinity and insufficient structural stability strongly restrict their practical applications.Coupling carbon nitrides with conductive carbon may relieve these issues.However,little is known about the influence of nitrogen(N)configurations on the interactions between carbon and C_(3)N_(4),which is fundamentally critical for guiding the precise design of advanced C_(3)N_(4)-related electrodes.Herein,highly crystalline C_(3)N_(4)(poly(triazine imide),PTI)based all-carbon composites were developed by molten salt strategy.More importantly,the vital role of pyrrolic-N for enhancing charge transfer and boosting Na+storage of C_(3)N_(4)-based composites,which was confirmed by both theoretical and experimental evidence,was spot-highlighted for the first time.By elaborately controlling the salt composition,the composite with high pyrrolic-N and minimized graphitic-N content was obtained.Profiting from the formation of highly crystalline PTI and electrochemically favorable pyrrolic-N configurations,the composite delivered an unusual reverse growth and record-level cycling stability even after 5000 cycles along with high reversible capacity and outstanding full-cell capacity retention.This work broadens the energy storage applications of C_(3)N_(4) and provides new prospects for the design of advanced all-carbon electrodes.展开更多
Graphitic carbon nitride(g-C_(3)N_(4))is emerging as a promising visible-light photocatalyst while the low crystallinity with sluggish charge separation/migration dynamics significantly restricts its practical applicat...Graphitic carbon nitride(g-C_(3)N_(4))is emerging as a promising visible-light photocatalyst while the low crystallinity with sluggish charge separation/migration dynamics significantly restricts its practical applications.Currently,synthesizing highly crystalline g-C_(3)N_(4) with sufficient surface activities still remains challenging.Herein,different from using alkali molten salts which is commonly reported,we propose an approach for synthesis of highly crystalline g-C_(3)N_(4) with FeCl3/KCl rock/molten mixed salts.The rock salt can serve as the structure-directing template while molten salt provides the required liquid medium for re-condensation.Intriguingly,the synthesized photocatalyst showed further enhanced crystallinity and improved surface area along with high p/p*excitation compared with crystalline C_(3)N_(4) prepared from conventional molten-salt methods.These catalytically advantageous features lead to its superior photocatalytic and piezocatalytic activities with a high reactivity for overall water splitting that is not commonly reported for C_(3)N_(4).This work provides an effective strategy for structural optimization of organic semiconductor based materials and may inspire new ideas for the design of advanced photocatalysts.展开更多
Constructing heterostructures with narrow-band-gap semiconductors is a promising strategy to extend light absorption range of graphitic carbon nitride(g-C_(3)N_(4))and simultaneously promote charge separation for its ...Constructing heterostructures with narrow-band-gap semiconductors is a promising strategy to extend light absorption range of graphitic carbon nitride(g-C_(3)N_(4))and simultaneously promote charge separation for its photocatalytic activity improvement.However,its highly localized electronic states of g-C_(3)N_(4)hinder photo-carrier migration through bulk towards heterostructure interfaces,resulting in low charge carrier separation efficiency of solid bulk g-C_(3)N_(4)-based heterostructures.Herein,porous g-C_(3)N_(4)(PCN)material with greatly shortened migration distance of photo-carriers from bulk to surface was used as an effective substrate to host Cd Se quantum dots to construct type II heterostructure of Cd Se/PCN for photocatalytic hydrogen production.The homogeneous modification of the Cd Se quantum dots throughout the whole bulk of PCN together with proper band alignments between Cd Se and PCN enables the effective separation of photo-generated charge carriers in the heterostructure.Consequently,the Cd Se/PCN heterostructure photocatalyst gives the greatly enhanced photocatalytic hydrogen production activity of192.3μmol h^(-1),which is 4.4 and 8.1 times that of Cd Se and PCN,respectively.This work provides a feasible strategy to construct carbon nitride-based heterostructure photocatalysts for boosting visible light driven water splitting performance.展开更多
In the early Galaxy,elemental abundances of the extremely metal-poor(EMP)stars contain abundant information about the neutron-capture nucleosynthesis and the chemical enrichment history.In this work,we study the abund...In the early Galaxy,elemental abundances of the extremely metal-poor(EMP)stars contain abundant information about the neutron-capture nucleosynthesis and the chemical enrichment history.In this work,we study the abundance characteristics of Sr and Ba for the EMP stars in the[Sr/Ba]vs.[Ba/Fe]space.We find that there are three boundaries for the distribution region of the EMP stars.The weak rprocess star CS 22897-008 lies on the upper end and the main r-process stars lie on the right end of the region.Near the right boundary of the distribution region,there is an Fe-normal belt.For the EMP stars in the belt,element Fe dominantly originates from the normal massive stars.The low-Sr stars([Sr/Fe]6−0.3)distribute in the region of the lower left of the Fe-normal belt and their Fe should originate partly from the prompt inventory.We find that the formation of the lower boundary of the distribution region is due to the pollution of the main r-process material and the formation of the right boundary could be explained by the combination of the weak r-and main r-process material.Furthermore,the formation of the left boundary is due to the pollution of the weak r-process material.Although the[Sr/Ba]ratios are related to the relative importance of the weak r-process material,the scatter of[Sr/Ba]ratios for the EMP stars mainly depends on the abundance ratio of the weak r-process.展开更多
Firstly,the behavior of marine science and technology talents,such as scientific research,innovation,agglomeration and flow behavior,was analyzed,and then the problems in the training of marine science and technology ...Firstly,the behavior of marine science and technology talents,such as scientific research,innovation,agglomeration and flow behavior,was analyzed,and then the problems in the training of marine science and technology talents were discussed.Finally,the training ways of marine science and technology talents were proposed.展开更多
Black phosphorus(BP)is a rapidly up and coming star in two-dimensional(2D)materials.The unique characteristic of BP is its in-plane anisotropy.This characteristic of BP ignites a new type of 2D materials that have low...Black phosphorus(BP)is a rapidly up and coming star in two-dimensional(2D)materials.The unique characteristic of BP is its in-plane anisotropy.This characteristic of BP ignites a new type of 2D materials that have low-symmetry structures and in-plane anisotropic properties.On this basis,they offer richer and more unique low-dimensional physics compared to isotropic 2D materials,thus providing a fertile ground for novel applications including electronics,optoelectronics,molecular detection,thermoelectric,piezoelectric,and ferroelectric with respect to in-plane anisotropy.This article reviews the recent advance in characterization and applications of in-plane anisotropic 2D materials.展开更多
Photocatalytic overall water splitting(OWS)without using any sacrificial reagent to realize H_(2)and O_(2)production in the stoichiometric ratio of 2:1 is viewed as the“holy grail”in the field of solar fuel producti...Photocatalytic overall water splitting(OWS)without using any sacrificial reagent to realize H_(2)and O_(2)production in the stoichiometric ratio of 2:1 is viewed as the“holy grail”in the field of solar fuel production.Developing stable,low cost,and nontoxic photocatalysts that have satisfactory solar-tohydrogen conversion efficiency is of significance but challenging for realizing the large-scale use of this sustainable technology.Among various photocatalysts,graphitic carbon nitride(GCN)has shown great potential as an ideal candidate to fulfill the breakthrough in this dynamic research field due to its attractive physicochemical properties.Herein,for the first time,the state-ofthe-art research progress of GCN for photocatalytic OWS is reviewed.We first summarize the basic principle of photocatalytic OWS along with the advantages/challenges of GCN introduced.The strategies that have been used to modulate the OWS activity of GCN are then reviewed,including cocatalyst investigation,morphology modulation,atomic structure modification,crystallinity engineering,and heterostructure construction.Toward the end of the review,the concluding remarks and perspectives for the future development are presented,with our expectation to provide some new ideas for the design of advanced OWS photocatalysts.展开更多
The high electrical conductivity makes it possible for one-dimensional(1D)carbon materials to be used as the promising anodes for potassium ion batteries(PIBs),however,the sluggish diffusion kinetics caused by large-s...The high electrical conductivity makes it possible for one-dimensional(1D)carbon materials to be used as the promising anodes for potassium ion batteries(PIBs),however,the sluggish diffusion kinetics caused by large-sized potassium ions(K^(+))limits their practical applications in energy storage systems.In this work,hollow carbon nanorods were rationally designed as a case to verify the superiority of 1D hollow structure to improve the diffusion kinetics of K^(+).Simultaneously,edge-N(pyridinic-N and pyrrolic-N)atoms were also introduced into 1D hollow carbon structure,which can provide ample active sites and defects in graphitic lattices to adsorb K^(+),providing extra capacitive storage capacity.As expected,the optimized edge-N doped hollow carbon nanorods(ENHCRs)exhibits a high reversible capacity of 544 mAh·g^(−1)at 0.1 A·g^(−1)after 200 cycles.Even at 5 A·g^(−1),it displays a long-term cycling stability with 255 mAh·g^(−1)over 10,000 cycles.The electrochemical measurements confirm that the hollow structure is favorable to improve the transfer kinetics of K^(+)during cycling.And the theoretical calculations demonstrate that edge-N doping can enhance the local electronegativity of graphitic lattices to adsorb much more K^(+),where edge-N doping synergizes with 1D hollow structure to achieve enhanced K^(+)-storage performances.展开更多
Ineffective control of dendrite growth and side reactions on Zn anodes significantly retards commercialization of aqueous Zn-ion batteries.Unlike conventional interfacial modification strategies that are primarily foc...Ineffective control of dendrite growth and side reactions on Zn anodes significantly retards commercialization of aqueous Zn-ion batteries.Unlike conventional interfacial modification strategies that are primarily focused on component optimization or microstructural tuning,herein,we propose a crystallinity engineering strategy by developing highly crystalline carbon nitride protective layers for Zn anodes through molten salt treatment.Interestingly,the highly ordered structure along with sufficient functional polar groups and pre-intercalated Kþendows the coating with high ionic conductivity,strong hydrophilicity,and accelerated ion diffusion kinetics.Theoretical calculations also confirm its enhanced Zn adsorption capability compared to commonly reported carbon nitride with amorphous or semi-crystalline structure and bare Zn.Benefiting from the aforementioned features,the as-synthesized protective layer enables a calendar lifespan of symmetric cells for 1100 h and outstanding stability of full cells with capacity retention of 91.5%after 1500 cycles.This work proposes a new conceptual strategy for Zn anode protection.展开更多
基金the National Natural Science Foundation of China(51904059,51574062,51902045)Fundamental Research Funds for the Central Universities(N182505036,N182503030,N2002005)Liao Ning Revitalization Talents Program(XLYC1807123)。
文摘Graphitic carbon nitride(g-C_(3)N_(4))with the merits of high visible light absorption,proper electronic band structure with high conduction band edge and variable modulation,is viewed as a promising photocatalyst for practical use.To alleviate its high recombination rate of photo-excited charge carriers and maximize the photocatalytic performances,it is paramount to design highly effective transfer channels for photo-excited charge carriers.Ferroelectric materials can have the charge carriers transport in opposite directions owing to the internal spontaneous polarization,which may be suitable for constructing the heterostructure with g-C_(3)N_(4)for efficient charge separation.Inspired by this concept,herein ferroelectric PbTiO_(3),which can be the visible-light absorber,is coupled with g-C_(3)N_(4)to construct PbTiO_(3)/g-C_(3)N_(4)heterostructure with close contact via Pb–N bond by the facile post thermal treatment.The optimized Pb TiO_(3)/g-C_(3)N_(4)heterostructure exhibited excellent photocatalytic and photoelectrochemical activities under visible light irradiation.Moreover,the simultaneous application of ultrasound-induced mechanical waves can further improve its photocatalytic activities through reinforcing the built-in piezoelectric field.This work proposes a widely applicable strategy for the fabrication of high-performance ferroelectric based photocatalysts and also provides some new ideas for developing the understanding of ferroelectric photocatalysis.
基金supported by the National Natural Science Foundation of China (Nos. 51825204 and 52072379)。
文摘To acquire efficient photocatalysts,it is necessary to make effective use of visible light/Near Infrared(NIR)light,which takes up a large percentage of sunlight.Integrating upconversion materials with visible light active photocatalysts has attracted much attention in this regard.The interface contact between upcon-version material and photocatalyst has potential influence on the properties and thus the performance of the system.In this work,NaYF_(4):Yb,Er/CdS composites of the upconversion material NaYF_(4):Yb,Er nanorods and CdS nanoparticles were synthesized by ion adsorption/precipitation process and were then annealed in an argon atmosphere at different temperatures to modulate the microstructures.The annealing pro-cess endows the crystal transformation of cubic CdS with low crystallinity to hexagonal CdS with high crystallinity and,importantly,good interface contact between NaYF_(4):Yb,Er and CdS.Consequently,the hy-drogen evolution activity greatly increases from 171 to 2539μmol h^(−1) g^(−1) under the light irradiation ofλ>400 nm,and from 0 to 19μmol h^(−1) g^(−1) under the light irradiation ofλ>600 nm.This work might provide a useful reference for the rational design of promising photocatalyst involving upconversion ma-terials.
基金supported by the National Natural Science Foundation of China(51902045,51904059)Fundamental Research Funds for the Central Universities(N182503030,N182505036,N2002005)+1 种基金Liao Ning Revitalization Talents Program(XLYC1807123)Young Elite Scientist Sponsorship Program by CAST(YESS)2019-2021QNRC.
文摘Graphitic carbon nitride(g-C_(3)N_(4))is viewed as a promising visible-light photocatalyst for industrialization due to its low processing temperature and high chemical stability.However,serious charge recombination caused by incomplete polymerization during direct calcination of nitrogen-rich precursors significantly limits its photocatalytic performances.To boost charge separation,herein,we propose a rational strategy by constructing a crystalline g-C_(3)N_(4)/g-C_(3)N_(4-x)S_(x) isotype heterostructure through the molten salt method.Theoretical calculation reveals that apparent charge-transfer channels are formed between g-C_(3)N_(4) and S-doped g-C_(3)N_(4) layers in the heterostructure.Owing to high crystallinity for decreasing charge recombination and isotype heterostructure for efficient charge transfer,the as-prepared g-C_(3)N_(4)/g-C_(3)N_(4-x)S_(x) showed remarkable photocatalytic performances with the hydrogen production rate elevated by up to 12.3 times of its singular components.Another novelty of this work is we investigated for the first time the piezocatalytic activity of crystalline g-C_(3)N_(4) by characterizing its performance for H2O2 generation and KMnO4 reduction.Strikingly,its superior piezocatalytic performance over components can be further improved by NaBH4 treatment,which is uncovered to enhance the asymmetric structure of crystalline g-C_(3)N_(4) by introducing extra cyano groups and removing partial NHx species in its tri-s-triazine layer structure.This work opens up new strategies for the design of highly efficient polymeric photocatalysts and highlights the piezocatalytic studies of g-C_(3)N_(4).
基金supported by the National Natural Science Foundation of China(51904059)Applied Basic Research Program of Liaoning(2022JH2/101300200)+1 种基金Guangdong Basic and Applied Basic Research Foundation(2022A1515140188)Fundamental Research Funds for the Central Universities(N_(2)002005,N_(2)125004,N_(2)225044)。
文摘Carbon nitrides with two-dimensional layered structures and high theoretical capacities are attractive as anode materials for sodium-ion batteries while their low crystallinity and insufficient structural stability strongly restrict their practical applications.Coupling carbon nitrides with conductive carbon may relieve these issues.However,little is known about the influence of nitrogen(N)configurations on the interactions between carbon and C_(3)N_(4),which is fundamentally critical for guiding the precise design of advanced C_(3)N_(4)-related electrodes.Herein,highly crystalline C_(3)N_(4)(poly(triazine imide),PTI)based all-carbon composites were developed by molten salt strategy.More importantly,the vital role of pyrrolic-N for enhancing charge transfer and boosting Na+storage of C_(3)N_(4)-based composites,which was confirmed by both theoretical and experimental evidence,was spot-highlighted for the first time.By elaborately controlling the salt composition,the composite with high pyrrolic-N and minimized graphitic-N content was obtained.Profiting from the formation of highly crystalline PTI and electrochemically favorable pyrrolic-N configurations,the composite delivered an unusual reverse growth and record-level cycling stability even after 5000 cycles along with high reversible capacity and outstanding full-cell capacity retention.This work broadens the energy storage applications of C_(3)N_(4) and provides new prospects for the design of advanced all-carbon electrodes.
基金supported by the National Natural Science Foundation of China(51902045,51904059)Fundamental Research Funds for the Central Universities(N2002005,N2125004,N2225038,N2225044)+2 种基金Applied Basic Research Program of Liaoning(2022JH2/101300200)Young Elite Scientist Sponsorship Program by CAST(YESS)2019-2021QNRCNational Research Foundation of Korea(NRF)grant funded by the Korean government(Ministry of Science,ICT&Future Planning)(NRF-2020R1F1A1075601 and NRF-2021R1A4A2001658).
文摘Graphitic carbon nitride(g-C_(3)N_(4))is emerging as a promising visible-light photocatalyst while the low crystallinity with sluggish charge separation/migration dynamics significantly restricts its practical applications.Currently,synthesizing highly crystalline g-C_(3)N_(4) with sufficient surface activities still remains challenging.Herein,different from using alkali molten salts which is commonly reported,we propose an approach for synthesis of highly crystalline g-C_(3)N_(4) with FeCl3/KCl rock/molten mixed salts.The rock salt can serve as the structure-directing template while molten salt provides the required liquid medium for re-condensation.Intriguingly,the synthesized photocatalyst showed further enhanced crystallinity and improved surface area along with high p/p*excitation compared with crystalline C_(3)N_(4) prepared from conventional molten-salt methods.These catalytically advantageous features lead to its superior photocatalytic and piezocatalytic activities with a high reactivity for overall water splitting that is not commonly reported for C_(3)N_(4).This work provides an effective strategy for structural optimization of organic semiconductor based materials and may inspire new ideas for the design of advanced photocatalysts.
基金financially supported by the National Natural Science Foundation of China(Nos.52002377,51825204 and 21633009)the China Postdoctoral Science Foundation(Nos.2020M681003 and 2020TQ0327)the Natural Science Foundation of Liaoning Province(No.2020BS009)。
文摘Constructing heterostructures with narrow-band-gap semiconductors is a promising strategy to extend light absorption range of graphitic carbon nitride(g-C_(3)N_(4))and simultaneously promote charge separation for its photocatalytic activity improvement.However,its highly localized electronic states of g-C_(3)N_(4)hinder photo-carrier migration through bulk towards heterostructure interfaces,resulting in low charge carrier separation efficiency of solid bulk g-C_(3)N_(4)-based heterostructures.Herein,porous g-C_(3)N_(4)(PCN)material with greatly shortened migration distance of photo-carriers from bulk to surface was used as an effective substrate to host Cd Se quantum dots to construct type II heterostructure of Cd Se/PCN for photocatalytic hydrogen production.The homogeneous modification of the Cd Se quantum dots throughout the whole bulk of PCN together with proper band alignments between Cd Se and PCN enables the effective separation of photo-generated charge carriers in the heterostructure.Consequently,the Cd Se/PCN heterostructure photocatalyst gives the greatly enhanced photocatalytic hydrogen production activity of192.3μmol h^(-1),which is 4.4 and 8.1 times that of Cd Se and PCN,respectively.This work provides a feasible strategy to construct carbon nitride-based heterostructure photocatalysts for boosting visible light driven water splitting performance.
基金This work has been supported by the National Natural Science Foundation of China under grants 11673007,11547041,11643007,and 11773009the Natural Science Foundation of Hebei Province under grants A2018106014 and A2019208194。
文摘In the early Galaxy,elemental abundances of the extremely metal-poor(EMP)stars contain abundant information about the neutron-capture nucleosynthesis and the chemical enrichment history.In this work,we study the abundance characteristics of Sr and Ba for the EMP stars in the[Sr/Ba]vs.[Ba/Fe]space.We find that there are three boundaries for the distribution region of the EMP stars.The weak rprocess star CS 22897-008 lies on the upper end and the main r-process stars lie on the right end of the region.Near the right boundary of the distribution region,there is an Fe-normal belt.For the EMP stars in the belt,element Fe dominantly originates from the normal massive stars.The low-Sr stars([Sr/Fe]6−0.3)distribute in the region of the lower left of the Fe-normal belt and their Fe should originate partly from the prompt inventory.We find that the formation of the lower boundary of the distribution region is due to the pollution of the main r-process material and the formation of the right boundary could be explained by the combination of the weak r-and main r-process material.Furthermore,the formation of the left boundary is due to the pollution of the weak r-process material.Although the[Sr/Ba]ratios are related to the relative importance of the weak r-process material,the scatter of[Sr/Ba]ratios for the EMP stars mainly depends on the abundance ratio of the weak r-process.
基金Supported by Foundation for Humanities and Social Sciences Research Planning of Ministry of Education of China in 2019(19YJA630058)
文摘Firstly,the behavior of marine science and technology talents,such as scientific research,innovation,agglomeration and flow behavior,was analyzed,and then the problems in the training of marine science and technology talents were discussed.Finally,the training ways of marine science and technology talents were proposed.
基金This work was supported by the National Natural Science Foundation of China(Grant No.21825103 and 51727809)the National Basic Research Foundation of China(Grant No.2015CB932600)the Project Funded by China Postdoctoral Science Foundation(Grant No.2017M610474,2016M600589,and 2017T100552).
文摘Black phosphorus(BP)is a rapidly up and coming star in two-dimensional(2D)materials.The unique characteristic of BP is its in-plane anisotropy.This characteristic of BP ignites a new type of 2D materials that have low-symmetry structures and in-plane anisotropic properties.On this basis,they offer richer and more unique low-dimensional physics compared to isotropic 2D materials,thus providing a fertile ground for novel applications including electronics,optoelectronics,molecular detection,thermoelectric,piezoelectric,and ferroelectric with respect to in-plane anisotropy.This article reviews the recent advance in characterization and applications of in-plane anisotropic 2D materials.
基金National Natural Science Foundation of China,Grant/Award Numbers:51902045,51904059Young Elite Scientist Sponsorship Program,Grant/Award Number:2019-2021QNRC+1 种基金Liao Ning Revitalization Talents Program,Grant/Award Number:XLYC1807123Fundamental Research Funds for the Central Universities,Grant/Award Numbers:N2002005,N182505036,N182503030。
文摘Photocatalytic overall water splitting(OWS)without using any sacrificial reagent to realize H_(2)and O_(2)production in the stoichiometric ratio of 2:1 is viewed as the“holy grail”in the field of solar fuel production.Developing stable,low cost,and nontoxic photocatalysts that have satisfactory solar-tohydrogen conversion efficiency is of significance but challenging for realizing the large-scale use of this sustainable technology.Among various photocatalysts,graphitic carbon nitride(GCN)has shown great potential as an ideal candidate to fulfill the breakthrough in this dynamic research field due to its attractive physicochemical properties.Herein,for the first time,the state-ofthe-art research progress of GCN for photocatalytic OWS is reviewed.We first summarize the basic principle of photocatalytic OWS along with the advantages/challenges of GCN introduced.The strategies that have been used to modulate the OWS activity of GCN are then reviewed,including cocatalyst investigation,morphology modulation,atomic structure modification,crystallinity engineering,and heterostructure construction.Toward the end of the review,the concluding remarks and perspectives for the future development are presented,with our expectation to provide some new ideas for the design of advanced OWS photocatalysts.
基金the National Natural Science Foundation of China(Nos.21601003,21972145,22102169,and 52172172)Natural Science Foundation of Anhui Province(No.2108085MB57)China Postdoctoral Science Foundation funded project(No.BH2340000137).
文摘The high electrical conductivity makes it possible for one-dimensional(1D)carbon materials to be used as the promising anodes for potassium ion batteries(PIBs),however,the sluggish diffusion kinetics caused by large-sized potassium ions(K^(+))limits their practical applications in energy storage systems.In this work,hollow carbon nanorods were rationally designed as a case to verify the superiority of 1D hollow structure to improve the diffusion kinetics of K^(+).Simultaneously,edge-N(pyridinic-N and pyrrolic-N)atoms were also introduced into 1D hollow carbon structure,which can provide ample active sites and defects in graphitic lattices to adsorb K^(+),providing extra capacitive storage capacity.As expected,the optimized edge-N doped hollow carbon nanorods(ENHCRs)exhibits a high reversible capacity of 544 mAh·g^(−1)at 0.1 A·g^(−1)after 200 cycles.Even at 5 A·g^(−1),it displays a long-term cycling stability with 255 mAh·g^(−1)over 10,000 cycles.The electrochemical measurements confirm that the hollow structure is favorable to improve the transfer kinetics of K^(+)during cycling.And the theoretical calculations demonstrate that edge-N doping can enhance the local electronegativity of graphitic lattices to adsorb much more K^(+),where edge-N doping synergizes with 1D hollow structure to achieve enhanced K^(+)-storage performances.
基金National Natural Science Foundation of China,Grant/Award Number:22378055Applied Basic Research Program of Liaoning,Grant/Award Number:2022JH2/101300200+1 种基金Guangdong Basic and Applied Basic Research Foundation,Grant/Award Number:2022A1515140188Fundamental Research Funds for the Central Universities,Grant/Award Numbers:N2002005,N2125004,N2225044,N232410019。
文摘Ineffective control of dendrite growth and side reactions on Zn anodes significantly retards commercialization of aqueous Zn-ion batteries.Unlike conventional interfacial modification strategies that are primarily focused on component optimization or microstructural tuning,herein,we propose a crystallinity engineering strategy by developing highly crystalline carbon nitride protective layers for Zn anodes through molten salt treatment.Interestingly,the highly ordered structure along with sufficient functional polar groups and pre-intercalated Kþendows the coating with high ionic conductivity,strong hydrophilicity,and accelerated ion diffusion kinetics.Theoretical calculations also confirm its enhanced Zn adsorption capability compared to commonly reported carbon nitride with amorphous or semi-crystalline structure and bare Zn.Benefiting from the aforementioned features,the as-synthesized protective layer enables a calendar lifespan of symmetric cells for 1100 h and outstanding stability of full cells with capacity retention of 91.5%after 1500 cycles.This work proposes a new conceptual strategy for Zn anode protection.
