Based on vibration analysis, single-layered graphene sheet （SLGS） with multiple attached nanoparticles is developed as nanoscale mass sensor in thermal environments. Graphene sensors are assumed to be in simplysuppo...Based on vibration analysis, single-layered graphene sheet （SLGS） with multiple attached nanoparticles is developed as nanoscale mass sensor in thermal environments. Graphene sensors are assumed to be in simplysupported configuration. Based on the nonlocal plate the- ory which incorporates size effects into the classical theory, closed-form expressions lot the frequencies and relative fre- quency shills of SLGS-based mass sensor are derived using the Galerkin method. The suggested model is justified by a good agreement between the results given by the present model and available data in literature. The effects of tem- perature difference, nonlocal parameter, the location of the nanoparticle and the number of nanoparticles on the relative frequency shift of the mass sensor are also elucidated. The obtained results show that the sensitivity of the SLGS- based mass sensor increases with increasing temperature difference.展开更多
The nature of DNA-graphene interaction system was investigated by using molecular dynamic simulations and density functional theory calculations. The detailed adsorption behaviors of single-stranded DNA( ssDNA) and do...The nature of DNA-graphene interaction system was investigated by using molecular dynamic simulations and density functional theory calculations. The detailed adsorption behaviors of single-stranded DNA( ssDNA) and double-stranded DNA( dsDNA) on the surface of graphene were discussed. The π-π stacking would contribute to the maximum average loading of ssDNA( 167 segments) with the adsorption potential distribution at the range of-6. 0 eV to-2. 1 eV,higher than that of dsDNA( 30 segments) with the adsorption energy distribution ranging from-3. 0 eV to- 0. 2 eV. Gradually shielding the base of ssDNA using hydrogen atom and gradually changing ssDNA into dsDNA through base-pairing were performed to further detect the detailed interaction between DNA and graphene. E B for * CGC,G* GC,GC* C,and GCG* is-15. 130,-15. 276,-15. 137,and- 15. 271 eV,respectively. E B for GCGC-CGCG / graphene,GCGC-CGC / graphene,GCGC-CG / graphene,GCGC-C / graphene,and GCGC / graphene is-14. 941,-14. 700,-14. 204,-15. 561,and- 15. 810 eV,respectively. DOS of the adsorbed ssDNA down shifted 1. 885 eV,which becomes more stable and less reactive than the other cases. Further,oxidation reaction shows that graphene protects ssDNA from breaking by active oxide. And stable adsorption,protection from destroying,and undamaged desorption insure the possibility of graphene to deliver or hybrid DNA for novel and creative use.展开更多
Graphene has been recognized as a promising 2D material with many new properties. However, pristine graphene is gapless which hinders its direct application towards graphene-based semiconducting devices. Recently, var...Graphene has been recognized as a promising 2D material with many new properties. However, pristine graphene is gapless which hinders its direct application towards graphene-based semiconducting devices. Recently, various ways have been proposed to overcome this problem. In this study, we report a robust method to open a gap in graphene via noncovalent functionalization with porphyrin molecules. Two type of porphyrins, namely, iron protoporphyrin (FePP) and zinc protoporphryin (ZnPP) were independently physisorbed on graphene grown on nickel by chemical vapour deposition (CVD) resulting in a bandgap opening in graphene. Using a statistical analysis of scanning tunneling spectroscopy (STS) measurements, we demonstrated that the magnitude of the band gap depends on the type of deposited porphyrin molecule.The π-π stacking of FePP on graphene yielded a considerably larger band gap value (0.45 eV) than physisorbed ZnPP (0.23 eV). We proposed that the origin of different band gap value is governed due to the metallic character of the respective porphyrin.展开更多
The rational design and preparation of promising cathode electrocatalysts with excellent activity and strong stability for metal-air batteries is a huge challenge.In this work,we innovate an approach of combining solv...The rational design and preparation of promising cathode electrocatalysts with excellent activity and strong stability for metal-air batteries is a huge challenge.In this work,we innovate an approach of combining solvothermal with high-temperature pyrolysis utilizing zeolitic imidazolate framework(ZIF)-8 and ZIF-67 as the template to synthesize a novel hybrid material of hierarchical porous yolk-shell Co-N-C polyhedron nanocatalysts engaged in graphene nanopocket(yolk-shell Co-N-C@GNP).The obtained catalyst exhibits prominent bifunctional electrocatalytic performance for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)in the alkaline condition,in which the half-wave potential is 0.86 V for ORR,and the over-potential for OER is 0.42 V at 10 mA·cm^(-2).The rechargeable aqueous Zn-air battery fabricated with yolk-shell Co-N-C@GNP cathode deliveries an open circuit voltage(OCV)of 1.60 V,a peak power density of 236.2 mW·cm^(-2),and excellent cycling stability over 94 h at 5 mA·cm^(-2).The quasi-solid-state Zn-air battery(ZAB)using yolk-shell Co-N-C@GNP displays a high OCV of 1.40 V and a small voltage gap of 0.88 V in continuous cycling tests at 2 mA·cm^(-2).This work provides a valuable thought to focus attention on the design of high-efficient bifunctional catalysts with hierarchical porous yolk-shell framework and high-density metal active sites for metal-air battery technologies.展开更多
Penta-graphene （PG）,a newly proposed two-dimensional material composed entirely of carbon pentagons,is believed to possess much lower failure stress and strain than those of graphene.An open question is whether and ...Penta-graphene （PG）,a newly proposed two-dimensional material composed entirely of carbon pentagons,is believed to possess much lower failure stress and strain than those of graphene.An open question is whether and how these properties can be enhanced.Herein using molecular dynamics simulations,we examine the deformation and failure processes of PG functionalized with different functional groups.We reveal that complete chemical functionalization leads to remarkable increases in the failure stress and strain of PG by up to 86.6% and 82.4%,respectively.The underlying reason for this enhancement is that the buckled pentagonal rings in pristine and partially functionalized PGs can easily transform into planar polygon rings under stretching;in contrast,complete functionalization of PG strongly stabilizes its structure and prevents such transformation,thereby significantly increasing the failure stress and strain.Our findings suggest a possible route to enhance the mechanical properties of PG for potential applications in nanocomposites and nanodevices.展开更多
Lightweight yet strong paper with high toughness is desirable especially for impact protection. Herein we demonstrated electrically conductive and mechanically robust paper(AP/PB-GP) made of reduced graphene oxide via...Lightweight yet strong paper with high toughness is desirable especially for impact protection. Herein we demonstrated electrically conductive and mechanically robust paper(AP/PB-GP) made of reduced graphene oxide via interfacial crosslinking with 1-aminopyrene(AP) and 1-pyrenebutyrat(PB) small molecules. The AP/PB-GP with thickness of over ten micrometer delivers a record-high toughness(~69.67 ± 15.3 MJ m^(-3) in average), simultaneously with superior strength(close to 1 GPa), allowing an impressive specific penetration energy absorption(~0.17 MJ kg^(-1)) at high impact velocities when used for ballistic impact protection. Detailed interfacial and structural analysis reveals that the reinforcement is synergistically determined by π-π interaction and H-bonding linkage between adjacent graphene lamellae. Especially, the defective pores within the graphene platelets benefit the favorable adsorption of the pyrene-containing molecules, which imperatively maximizes the interfacial binding, facilitating deflecting crack and plastic deformation under loading. Density functional theory simulation suggests that the coupling between the polar functional groups, e.g., –COOH, at the edges of graphene platelets and –NH_(2) and –COOH of AP/PB are critical to the formation of hydrogen bonding network.展开更多
Graphene/mono-(6-amino-6-deoxy)-β-cyclodextrin multilayer films composed of graphene sheet(GS)and mono-(6-amino-6-deoxy)-β-cyclodextrin(NH_(2)-β-CD)were fabricated easily by two steps.First,negatively charged graph...Graphene/mono-(6-amino-6-deoxy)-β-cyclodextrin multilayer films composed of graphene sheet(GS)and mono-(6-amino-6-deoxy)-β-cyclodextrin(NH_(2)-β-CD)were fabricated easily by two steps.First,negatively charged graphene oxide(GO)and positively charged mono-(6-amino-6-deoxy)-β-cyclodextrin(NH_(2)-β-CD)were layer-by-layer(LBL)self-assembled on glassy carbon electrode(GCE)modified with a layer of poly(diallyldimethylammo-nium chloride)(PDDA).Then graphene/mono-(6-amino-6-deoxy)-β-cyclodextrin(GS/NH_(2)-β-CD)multilayer films were built up by electrochemical reduction of graphene oxide/mono-(6-amino-6-deoxy)-β-cyclodextrin(GO/NH_(2)-β-CD).Combining the high surface area of GS and the active recognition sites onβ-cyclodextrin(β-CD),the GS/NH_(2)-β-CD multilayer films show excellent electrochemical sensing performance for the detection of DA with an extraordinary broad linear range from 2.53 to 980.05μmol•L^(−1).This study offers a simple route to the controlla-ble formation of graphene-based electrochemical sensor for the detection of DA.展开更多
A new s-triazine derivative modified graphene composite, in which 2,4,6-tri（2,4-dihydroxyphenyl）-1,3,5- triazine （TDTA） was attached onto reduced graphene oxide （rGO） via the noncovalent functionalization approa...A new s-triazine derivative modified graphene composite, in which 2,4,6-tri（2,4-dihydroxyphenyl）-1,3,5- triazine （TDTA） was attached onto reduced graphene oxide （rGO） via the noncovalent functionalization approach, named TDTA/rGO, was reported. And the TDTA was synthesized via a Friedel-Crafts reaction. FTIR and NMR spectroscopic characterizations were carried out to confirm the synthesis of TDTA. UV-Vis, XPS and TEM revealed that TDTA molecules were successfully loaded onto graphene sheets by π-π stacking, and the composite is found to improve greatly the dispersity ofrGO in DMF and to be a good UV-absorber.展开更多
Silicon photonics has become very popular because of their compatibility with mature CMOS technologies. However, pure silicon is still very difficult to be utilized to obtain various photonic functional devices for la...Silicon photonics has become very popular because of their compatibility with mature CMOS technologies. However, pure silicon is still very difficult to be utilized to obtain various photonic functional devices for large-scale photonic integration due to intrinsic properties. Silicon-plus photonics, which pluses other materials to break the limitation of silicon, is playing a very important role currently and in the future. In this paper, we give a review and discussion on the progresses of siliconplus photonics, including the structures, devices and applications.展开更多
Bionanosensors and nanosensors have been devised in recent years with the use of various materials including carbon-based nanomaterials, for applications in diagnostics, environmental science and microelectronics. Car...Bionanosensors and nanosensors have been devised in recent years with the use of various materials including carbon-based nanomaterials, for applications in diagnostics, environmental science and microelectronics. Carbon-based materials are critical for sensing applications, as they have physical and electronic properties which facilitate the detection of substances in solutions, gaseous compounds and pollutants through their conductive prop- erties and resonance-frequency transmission capacities. In this review, a series of recent studies of carbon nanotubes （CNTs） based nanosensors and optical systems are repor- ted, with emphasis on biochemical, chemical and envi- ronmental detection. This study also encompasses a background and description of the various properties of the nanomaterials, and the operation mechanism of the man- ufactured nanosensors. The use of computational chemistry is applied in describing the electronic properties and molecular events of the included nanomaterials during operation. This review shows that resonance-based sensing technologies reach detection limits for gases, such as ammonia down to 10-24 level. The study also shows that the properties of the carbon nanomaterials give them unique features that are critical for designing new sensors based on electrocatalysis and other reactive detection mechanisms. Several research fields can benefit from the described emerging technologies, such as areas of research in environmental monitoring, rapid-on site diagnostics, in situ analyses, and blood and urine sampling in medical and sport industry. Carbon nanomaterials are critical for the operational sensitivity of nanosensors. Considering the low cost of fabrication, carbon nanomaterials can represent an essential step in the manufacturing of tomorrow＇s commercial sensors.展开更多
文摘Based on vibration analysis, single-layered graphene sheet （SLGS） with multiple attached nanoparticles is developed as nanoscale mass sensor in thermal environments. Graphene sensors are assumed to be in simplysupported configuration. Based on the nonlocal plate the- ory which incorporates size effects into the classical theory, closed-form expressions lot the frequencies and relative fre- quency shills of SLGS-based mass sensor are derived using the Galerkin method. The suggested model is justified by a good agreement between the results given by the present model and available data in literature. The effects of tem- perature difference, nonlocal parameter, the location of the nanoparticle and the number of nanoparticles on the relative frequency shift of the mass sensor are also elucidated. The obtained results show that the sensitivity of the SLGS- based mass sensor increases with increasing temperature difference.
基金Sponsored by the National Natural Science Foundation of China(Grant No.51106051)
文摘The nature of DNA-graphene interaction system was investigated by using molecular dynamic simulations and density functional theory calculations. The detailed adsorption behaviors of single-stranded DNA( ssDNA) and double-stranded DNA( dsDNA) on the surface of graphene were discussed. The π-π stacking would contribute to the maximum average loading of ssDNA( 167 segments) with the adsorption potential distribution at the range of-6. 0 eV to-2. 1 eV,higher than that of dsDNA( 30 segments) with the adsorption energy distribution ranging from-3. 0 eV to- 0. 2 eV. Gradually shielding the base of ssDNA using hydrogen atom and gradually changing ssDNA into dsDNA through base-pairing were performed to further detect the detailed interaction between DNA and graphene. E B for * CGC,G* GC,GC* C,and GCG* is-15. 130,-15. 276,-15. 137,and- 15. 271 eV,respectively. E B for GCGC-CGCG / graphene,GCGC-CGC / graphene,GCGC-CG / graphene,GCGC-C / graphene,and GCGC / graphene is-14. 941,-14. 700,-14. 204,-15. 561,and- 15. 810 eV,respectively. DOS of the adsorbed ssDNA down shifted 1. 885 eV,which becomes more stable and less reactive than the other cases. Further,oxidation reaction shows that graphene protects ssDNA from breaking by active oxide. And stable adsorption,protection from destroying,and undamaged desorption insure the possibility of graphene to deliver or hybrid DNA for novel and creative use.
文摘Graphene has been recognized as a promising 2D material with many new properties. However, pristine graphene is gapless which hinders its direct application towards graphene-based semiconducting devices. Recently, various ways have been proposed to overcome this problem. In this study, we report a robust method to open a gap in graphene via noncovalent functionalization with porphyrin molecules. Two type of porphyrins, namely, iron protoporphyrin (FePP) and zinc protoporphryin (ZnPP) were independently physisorbed on graphene grown on nickel by chemical vapour deposition (CVD) resulting in a bandgap opening in graphene. Using a statistical analysis of scanning tunneling spectroscopy (STS) measurements, we demonstrated that the magnitude of the band gap depends on the type of deposited porphyrin molecule.The π-π stacking of FePP on graphene yielded a considerably larger band gap value (0.45 eV) than physisorbed ZnPP (0.23 eV). We proposed that the origin of different band gap value is governed due to the metallic character of the respective porphyrin.
基金This study was supported by the National Natural Science Foundation of China(Nos.22008058 and 52074119)the Joint Funds of National Natural Science Foundation of China(No.U20A20280)+3 种基金the program for Innovative Teams of Outstanding Young and Middle-aged Researchers in the Higher Education Institutions of Hubei Province(No.T2021010)the Joint supported by Hubei Provincial Natural Science Foundation and Huangshi of China(No.2022CFD039)the Postgraduate Innovative Research Project of Hubei Normal University(Nos.20220512 and 20220552)College Students innovation and entrepreneurship training program of Hubei Province(No.S202210513055).
文摘The rational design and preparation of promising cathode electrocatalysts with excellent activity and strong stability for metal-air batteries is a huge challenge.In this work,we innovate an approach of combining solvothermal with high-temperature pyrolysis utilizing zeolitic imidazolate framework(ZIF)-8 and ZIF-67 as the template to synthesize a novel hybrid material of hierarchical porous yolk-shell Co-N-C polyhedron nanocatalysts engaged in graphene nanopocket(yolk-shell Co-N-C@GNP).The obtained catalyst exhibits prominent bifunctional electrocatalytic performance for oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)in the alkaline condition,in which the half-wave potential is 0.86 V for ORR,and the over-potential for OER is 0.42 V at 10 mA·cm^(-2).The rechargeable aqueous Zn-air battery fabricated with yolk-shell Co-N-C@GNP cathode deliveries an open circuit voltage(OCV)of 1.60 V,a peak power density of 236.2 mW·cm^(-2),and excellent cycling stability over 94 h at 5 mA·cm^(-2).The quasi-solid-state Zn-air battery(ZAB)using yolk-shell Co-N-C@GNP displays a high OCV of 1.40 V and a small voltage gap of 0.88 V in continuous cycling tests at 2 mA·cm^(-2).This work provides a valuable thought to focus attention on the design of high-efficient bifunctional catalysts with hierarchical porous yolk-shell framework and high-density metal active sites for metal-air battery technologies.
基金The authors gratefully acknowledge the computational support provided by Intersect Australia Ltd and A＇STAR Computational Resource Centre of Singapore This work was partially supported by a grant from the Science and Engineering Research Council, A＇STAR, Singapore （152-70-00017）. H. J. G. acknowledges support from the National Science Foundation （No. CMMI-1634492）.
文摘Penta-graphene （PG）,a newly proposed two-dimensional material composed entirely of carbon pentagons,is believed to possess much lower failure stress and strain than those of graphene.An open question is whether and how these properties can be enhanced.Herein using molecular dynamics simulations,we examine the deformation and failure processes of PG functionalized with different functional groups.We reveal that complete chemical functionalization leads to remarkable increases in the failure stress and strain of PG by up to 86.6% and 82.4%,respectively.The underlying reason for this enhancement is that the buckled pentagonal rings in pristine and partially functionalized PGs can easily transform into planar polygon rings under stretching;in contrast,complete functionalization of PG strongly stabilizes its structure and prevents such transformation,thereby significantly increasing the failure stress and strain.Our findings suggest a possible route to enhance the mechanical properties of PG for potential applications in nanocomposites and nanodevices.
基金supported by the National Natural Science Foundation of China (51772282,51972299)funding from Hefei Center for Physical Science and Technology。
文摘Lightweight yet strong paper with high toughness is desirable especially for impact protection. Herein we demonstrated electrically conductive and mechanically robust paper(AP/PB-GP) made of reduced graphene oxide via interfacial crosslinking with 1-aminopyrene(AP) and 1-pyrenebutyrat(PB) small molecules. The AP/PB-GP with thickness of over ten micrometer delivers a record-high toughness(~69.67 ± 15.3 MJ m^(-3) in average), simultaneously with superior strength(close to 1 GPa), allowing an impressive specific penetration energy absorption(~0.17 MJ kg^(-1)) at high impact velocities when used for ballistic impact protection. Detailed interfacial and structural analysis reveals that the reinforcement is synergistically determined by π-π interaction and H-bonding linkage between adjacent graphene lamellae. Especially, the defective pores within the graphene platelets benefit the favorable adsorption of the pyrene-containing molecules, which imperatively maximizes the interfacial binding, facilitating deflecting crack and plastic deformation under loading. Density functional theory simulation suggests that the coupling between the polar functional groups, e.g., –COOH, at the edges of graphene platelets and –NH_(2) and –COOH of AP/PB are critical to the formation of hydrogen bonding network.
基金support from the Na-tional Natural Science Foundation of China(NSFC,Nos.51063003,21364004)the Ministry of Science and Technology Project(No.2009GJG10041)+2 种基金the Funda-mental Research Funds for the Universities of Gansu(No.1105ZTC136)the Natural Science Foundation of Gansu Province(No.1208RJZA173)the Doctoral Research Start-funded Projects of Lanzhou University of Technology.
文摘Graphene/mono-(6-amino-6-deoxy)-β-cyclodextrin multilayer films composed of graphene sheet(GS)and mono-(6-amino-6-deoxy)-β-cyclodextrin(NH_(2)-β-CD)were fabricated easily by two steps.First,negatively charged graphene oxide(GO)and positively charged mono-(6-amino-6-deoxy)-β-cyclodextrin(NH_(2)-β-CD)were layer-by-layer(LBL)self-assembled on glassy carbon electrode(GCE)modified with a layer of poly(diallyldimethylammo-nium chloride)(PDDA).Then graphene/mono-(6-amino-6-deoxy)-β-cyclodextrin(GS/NH_(2)-β-CD)multilayer films were built up by electrochemical reduction of graphene oxide/mono-(6-amino-6-deoxy)-β-cyclodextrin(GO/NH_(2)-β-CD).Combining the high surface area of GS and the active recognition sites onβ-cyclodextrin(β-CD),the GS/NH_(2)-β-CD multilayer films show excellent electrochemical sensing performance for the detection of DA with an extraordinary broad linear range from 2.53 to 980.05μmol•L^(−1).This study offers a simple route to the controlla-ble formation of graphene-based electrochemical sensor for the detection of DA.
文摘A new s-triazine derivative modified graphene composite, in which 2,4,6-tri（2,4-dihydroxyphenyl）-1,3,5- triazine （TDTA） was attached onto reduced graphene oxide （rGO） via the noncovalent functionalization approach, named TDTA/rGO, was reported. And the TDTA was synthesized via a Friedel-Crafts reaction. FTIR and NMR spectroscopic characterizations were carried out to confirm the synthesis of TDTA. UV-Vis, XPS and TEM revealed that TDTA molecules were successfully loaded onto graphene sheets by π-π stacking, and the composite is found to improve greatly the dispersity ofrGO in DMF and to be a good UV-absorber.
基金Acknowledgements This work was supported partially by the National Natural Science Foundation of China （Grant Nos. 61422510, 11374263 and 61431166001 ）, the Doctoral Fund of Ministry of Education of China （No. 20120101110094）, the Fundamental Research Funds for the Central Universities,
文摘Silicon photonics has become very popular because of their compatibility with mature CMOS technologies. However, pure silicon is still very difficult to be utilized to obtain various photonic functional devices for large-scale photonic integration due to intrinsic properties. Silicon-plus photonics, which pluses other materials to break the limitation of silicon, is playing a very important role currently and in the future. In this paper, we give a review and discussion on the progresses of siliconplus photonics, including the structures, devices and applications.
文摘Bionanosensors and nanosensors have been devised in recent years with the use of various materials including carbon-based nanomaterials, for applications in diagnostics, environmental science and microelectronics. Carbon-based materials are critical for sensing applications, as they have physical and electronic properties which facilitate the detection of substances in solutions, gaseous compounds and pollutants through their conductive prop- erties and resonance-frequency transmission capacities. In this review, a series of recent studies of carbon nanotubes （CNTs） based nanosensors and optical systems are repor- ted, with emphasis on biochemical, chemical and envi- ronmental detection. This study also encompasses a background and description of the various properties of the nanomaterials, and the operation mechanism of the man- ufactured nanosensors. The use of computational chemistry is applied in describing the electronic properties and molecular events of the included nanomaterials during operation. This review shows that resonance-based sensing technologies reach detection limits for gases, such as ammonia down to 10-24 level. The study also shows that the properties of the carbon nanomaterials give them unique features that are critical for designing new sensors based on electrocatalysis and other reactive detection mechanisms. Several research fields can benefit from the described emerging technologies, such as areas of research in environmental monitoring, rapid-on site diagnostics, in situ analyses, and blood and urine sampling in medical and sport industry. Carbon nanomaterials are critical for the operational sensitivity of nanosensors. Considering the low cost of fabrication, carbon nanomaterials can represent an essential step in the manufacturing of tomorrow＇s commercial sensors.
