Graphene quantum dots （GODs） recently emerge as the new and appealing nanophotocatalyst because of their low-cost, environmental compatibility and the ability to facilitate the charge migration and prolong the charg...Graphene quantum dots （GODs） recently emerge as the new and appealing nanophotocatalyst because of their low-cost, environmental compatibility and the ability to facilitate the charge migration and prolong the charge lifetimes. In this work, a visible photocatalyst of S-doped graphene quantum dots （S-GQDs） was prepared by a facile hydrothermal synthesis using 1,3,6-trinitropyrene and Na2S as precursors. The well crystallization and monodispersity as well as the chemical environment of S-GQDs were characterized by transmission electron microscopy, atom force microscopy and X-ray photoelectron spectrum. A superior photocatalytic performance of S-GQDs was demonstrated for degradation of basic fuchsin under visible light irradiation. Furthermore, the possible photocatalytic mechanism was proposed based on the trapping experiments of active species.展开更多
A novel three-dimensional (3D) layered MoS2@graphene functionalized with nitrogen-doped graphene quantum dots (MoS2@N-GQDs-GR) composites as an enhanced electrochemical hydrogen evolution catalyst. The few layered MoS...A novel three-dimensional (3D) layered MoS2@graphene functionalized with nitrogen-doped graphene quantum dots (MoS2@N-GQDs-GR) composites as an enhanced electrochemical hydrogen evolution catalyst. The few layered MoS2 nanoflowers supported on N-GQDs-GR surface were elaborately fabricated by one-pot hydrothermal method, which MoS2 and N-GQDs-GR exist in a bonding manner of Mo-N. In addition, due to the layered MoS2 sheet edge exposes more hydrogen evolution active sites and N-GQDs-GR have high conductivity, the composites exhibit prominent electrocatalytic activity with a low overpotential 99 mV, a small Tafel slope 49.3 mV/dec. Therefore, that the current work will develop HER catalysts may replace Pt.展开更多
Electrochemical N2 reduction offers a promising alternative to the Haber-Bosch process for sustainable NH3 synthesis at ambient conditions,but it needs efficient catalysts for the N2 reduction reaction(NRR).Here,we re...Electrochemical N2 reduction offers a promising alternative to the Haber-Bosch process for sustainable NH3 synthesis at ambient conditions,but it needs efficient catalysts for the N2 reduction reaction(NRR).Here,we report that FeOOH quantum dots decorated graphene sheet acts as a superior catalyst toward enhanced electrocatalytic N2 reduction to NH3 under ambient conditions.In 0.1 M LiClO4,this hybrid attains a large NH3 yield rate and a high Faradaic efficiency of 27.3µg·h^−1·mg−1cat.and 14.6%at−0.4 V vs.reversible hydrogen electrode,respectively,rivalling the current efficiency of all Fe-based NRR electrocatalysts in aqueous media.It also shows strong durability during the electrolytic process.展开更多
Ternary materials composed of boron,carbon,nitrogen have drawn tremendous attention because of their suitable band gap,high carrier mobility,high thermal conductivity.The properties can effectively compensate for the ...Ternary materials composed of boron,carbon,nitrogen have drawn tremendous attention because of their suitable band gap,high carrier mobility,high thermal conductivity.The properties can effectively compensate for the deficiencies of other typical carbon-based and boron-based materials,such as graphene,borophene,hexagonal boron nitride.Although the theoretical progress has advanced the development of ternary materials,it is still a great challenge to synthesize the new nanostructures with good crystallinity and high yield at low dimensional scales.Herein,we report that BC_(2)N quantum dots(QDs)can be successfully prepared by in-situ two-step thermal decomposition of sodium cyanoborohydride in a hydrogen-rich environment.The results show that the as-prepared BC_(2)N QDs have good crystallinity and high yield.The BC_(2)N QDs have an average lateral size of 3.7 nm and an average thickness of 2.83 nm.The experimental results show that the QDs are semiconducting with an optical band gap of 2.15 eV.Furthermore,a fabricated BC_(2)N QDs-based nonvolatile memory shows a low SET operating voltage(0.74 V)and a high ON/OFF ratio(more than 1.74×10^(3))as well as good stability.展开更多
Metallic Sn has provoked tremendous progress as an anode material for sodium-ion batteries(SIBs).However,Sn anodes suffer from a dramatic capacity fading,owing to pulverization induced by drastic volume expansion duri...Metallic Sn has provoked tremendous progress as an anode material for sodium-ion batteries(SIBs).However,Sn anodes suffer from a dramatic capacity fading,owing to pulverization induced by drastic volume expansion during cycling.Herein,a flexible three-dimensional(3D)hierarchical conductive network electrode is designed by constructing Sn quantum dots(QDs)encapsulated in one-dimensional N,S codoped carbon nanofibers(NS-CNFs)sheathed within two-dimensional(2D)reduced graphene oxide(rGO)scrolls.In this ingenious strategy,1D NS-CNFs are regarded as building blocks to prevent the aggregation and pulverization of Sn QDs during sodiation/desodiation,2D rGO acts as electrical roads and“bridges”among NS-CNFs to improve the conductivity of the electrode and enlarge the contact area with electrolyte.Because of the unique structural merits,the flexible 3D hierarchical conductive network was directly used as binder-and current collectorfree anode for SIBs,exhibiting ultra-long cycling life(373 mAh g?1 after 5000 cycles at 1 A g?1),and excellent high-rate capability(189 mAh g?1 at 10 A g?1).This work provides a facile and efficient engineering method to construct 3D hierarchical conductive electrodes for other flexible energy storage devices.展开更多
基金financial support from the Zhejiang Provincial Natural Science Foundation of China (Nos. LY17B050007, LY15B050006)521 Talent Project of ZSTU
文摘Graphene quantum dots （GODs） recently emerge as the new and appealing nanophotocatalyst because of their low-cost, environmental compatibility and the ability to facilitate the charge migration and prolong the charge lifetimes. In this work, a visible photocatalyst of S-doped graphene quantum dots （S-GQDs） was prepared by a facile hydrothermal synthesis using 1,3,6-trinitropyrene and Na2S as precursors. The well crystallization and monodispersity as well as the chemical environment of S-GQDs were characterized by transmission electron microscopy, atom force microscopy and X-ray photoelectron spectrum. A superior photocatalytic performance of S-GQDs was demonstrated for degradation of basic fuchsin under visible light irradiation. Furthermore, the possible photocatalytic mechanism was proposed based on the trapping experiments of active species.
基金financially supported by the National Natural Science Foundation of China(Nos. 21165016, 21175108, 21265018)the Science and Technology Support Projects of Gansu Province (Nos. 1011GKCA025, 090GKCA036,1208RJZM289)
文摘A novel three-dimensional (3D) layered MoS2@graphene functionalized with nitrogen-doped graphene quantum dots (MoS2@N-GQDs-GR) composites as an enhanced electrochemical hydrogen evolution catalyst. The few layered MoS2 nanoflowers supported on N-GQDs-GR surface were elaborately fabricated by one-pot hydrothermal method, which MoS2 and N-GQDs-GR exist in a bonding manner of Mo-N. In addition, due to the layered MoS2 sheet edge exposes more hydrogen evolution active sites and N-GQDs-GR have high conductivity, the composites exhibit prominent electrocatalytic activity with a low overpotential 99 mV, a small Tafel slope 49.3 mV/dec. Therefore, that the current work will develop HER catalysts may replace Pt.
基金supported by the National Natural Science Foundation of China(No.21575137).
文摘Electrochemical N2 reduction offers a promising alternative to the Haber-Bosch process for sustainable NH3 synthesis at ambient conditions,but it needs efficient catalysts for the N2 reduction reaction(NRR).Here,we report that FeOOH quantum dots decorated graphene sheet acts as a superior catalyst toward enhanced electrocatalytic N2 reduction to NH3 under ambient conditions.In 0.1 M LiClO4,this hybrid attains a large NH3 yield rate and a high Faradaic efficiency of 27.3µg·h^−1·mg−1cat.and 14.6%at−0.4 V vs.reversible hydrogen electrode,respectively,rivalling the current efficiency of all Fe-based NRR electrocatalysts in aqueous media.It also shows strong durability during the electrolytic process.
基金the National Natural Science Foundation of China(No.61774085)the Natural Science Foundation of Jiangsu Province(No.BK20201300)+5 种基金the Research Fund of State Key Laboratory of Mechanics and Control of Mechanical Structures,Nanjing University of Aeronautics and Astronautics(NUAA)(No.MCMS-I-0420G02)the Fundamental Research Funds for the Central Universities(No.NP2022401)the Fund of Prospective Layout of Scientific Research for NUAA(No.ILA22009)the Priority Academic Program Development of Jiangsu Higher Education Institutions,the Funding for Outstanding Doctoral Dissertation in NUAA(No.BCXJ22-02)the Interdisciplinary Innovation Fund for Doctoral Students of NUAA(No.KXKCXJJ202201)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX22_0329).
文摘Ternary materials composed of boron,carbon,nitrogen have drawn tremendous attention because of their suitable band gap,high carrier mobility,high thermal conductivity.The properties can effectively compensate for the deficiencies of other typical carbon-based and boron-based materials,such as graphene,borophene,hexagonal boron nitride.Although the theoretical progress has advanced the development of ternary materials,it is still a great challenge to synthesize the new nanostructures with good crystallinity and high yield at low dimensional scales.Herein,we report that BC_(2)N quantum dots(QDs)can be successfully prepared by in-situ two-step thermal decomposition of sodium cyanoborohydride in a hydrogen-rich environment.The results show that the as-prepared BC_(2)N QDs have good crystallinity and high yield.The BC_(2)N QDs have an average lateral size of 3.7 nm and an average thickness of 2.83 nm.The experimental results show that the QDs are semiconducting with an optical band gap of 2.15 eV.Furthermore,a fabricated BC_(2)N QDs-based nonvolatile memory shows a low SET operating voltage(0.74 V)and a high ON/OFF ratio(more than 1.74×10^(3))as well as good stability.
基金financially supported by the Natural Science Foundation of Shandong Province,China(ZR2018JL021,ZR2014EMQ011)the Applied Basic Research Foundation of Qingdao City(17-1-1-84-jch)+2 种基金the National Natural Science Foundation of China(51402160)supported by Taishan Scholar Program of Shandong Province,China,and National Demonstration Center for Experimental Applied Physics Education(Qingdao University)support from the China Postdoctoral Science Foundation Funded Project(2018M630747)and Qingdao Postdoctoral Applied Research Project.
文摘Metallic Sn has provoked tremendous progress as an anode material for sodium-ion batteries(SIBs).However,Sn anodes suffer from a dramatic capacity fading,owing to pulverization induced by drastic volume expansion during cycling.Herein,a flexible three-dimensional(3D)hierarchical conductive network electrode is designed by constructing Sn quantum dots(QDs)encapsulated in one-dimensional N,S codoped carbon nanofibers(NS-CNFs)sheathed within two-dimensional(2D)reduced graphene oxide(rGO)scrolls.In this ingenious strategy,1D NS-CNFs are regarded as building blocks to prevent the aggregation and pulverization of Sn QDs during sodiation/desodiation,2D rGO acts as electrical roads and“bridges”among NS-CNFs to improve the conductivity of the electrode and enlarge the contact area with electrolyte.Because of the unique structural merits,the flexible 3D hierarchical conductive network was directly used as binder-and current collectorfree anode for SIBs,exhibiting ultra-long cycling life(373 mAh g?1 after 5000 cycles at 1 A g?1),and excellent high-rate capability(189 mAh g?1 at 10 A g?1).This work provides a facile and efficient engineering method to construct 3D hierarchical conductive electrodes for other flexible energy storage devices.
