首先以Hummers法制备还原态氧化石墨烯(RGO),其次通过溶胶-凝胶法和水热法分别制备TiO_(2)和TiO_(2)/RGO复合材料,然后向硝酸银溶液滴加氨水沉淀出纳米Ag并掺杂到TiO_(2)上,再以聚乙烯吡咯烷酮(PVP)为分散剂,以RGO为基体材料,用一步水...首先以Hummers法制备还原态氧化石墨烯(RGO),其次通过溶胶-凝胶法和水热法分别制备TiO_(2)和TiO_(2)/RGO复合材料,然后向硝酸银溶液滴加氨水沉淀出纳米Ag并掺杂到TiO_(2)上,再以聚乙烯吡咯烷酮(PVP)为分散剂,以RGO为基体材料,用一步水热法合成Ag@TiO_(2)/RGO复合光催化剂。复合材料通过FT-IR、XRD、SEM、DRS和BET等进行结构、组成、形貌和孔径大小的表征。将Ag@TiO_(2)/RGO用来光催化降解罗丹明B(RhB)溶液,结果表明,0.020 g该催化剂对50 mL 5 mg/L的RhB溶液在pH值为5、室温条件下的降解效果最好;经6次循环利用后,降解率依然能达到80%。展开更多
1T-MoS_(2)nanosheets,with metallic conductivity and high capacity,hold great potential for lithium-ion capacitors(LICs),but suffer from sluggish reaction kinetics due to dense stacking.Herein,1T-MoS_(2)nanosheets with...1T-MoS_(2)nanosheets,with metallic conductivity and high capacity,hold great potential for lithium-ion capacitors(LICs),but suffer from sluggish reaction kinetics due to dense stacking.Herein,1T-MoS_(2)nanosheets with enlarged interlayer spacing,vertically bonded to reduced graphene oxide(rGO)(1T-MoS_(2)/rGO),were designed using a hydrothermal-assisted dispersion and intercalation strategy.The active nitrogen species derived from N,N-dimethylformamide(DMF)not only bridge the rGO and MoS_(2)through strong Mo-N-C bonds to promote the formation of dispersed MoS_(2)nanosheets,but also intercalate into the MoS_(2)structure,further enlarging the interlayer spacing.This unique structure synergistically enhances meso-and microscale mass transfer outside and inside of the few-layered nanosheets,significantly improving electrochemical reaction kinetics and reducing the kinetic mismatch between the anode and cathode.Consequently,the resulting 1T-MoS_(2)/rGO achieves a capacity of 500 mAh g^(-1)after 500 cycles at 5 A g^(-1)and a high rate performance of 587 mAh g^(-1)at a high rate of 10 A g^(-1).Moreover,the assembled 3D vertical 1T-MoS_(2)/rGO//AC LIC delivers a high energy density of 100.3 Wh kg^(-1)at a power density of1.0 kW kg^(-1),and long cycle stability with capacity retention as high as 91.02%after 5000 cycles at 2 A g^(-1).This work provides a generalizable strategy for engineering two-dimensional material-based electrodes,offering new insights into high-performance energy storage systems.展开更多
Direct borohydride hydrogen peroxide fuel cells(DBHPFCs)are emerging as a transformative technology for sustainable energy conversion.Despite their potential,their efficiency is largely hindered by the limitations of ...Direct borohydride hydrogen peroxide fuel cells(DBHPFCs)are emerging as a transformative technology for sustainable energy conversion.Despite their potential,their efficiency is largely hindered by the limitations of the anode catalyst.In response to this challenge,we have developed a novel series of Co-based heterojunction metal-organic framework(MOF)derivatives,supported on reduced graphene oxide(rGO)-modified nickel foam(NF),to enhance borohydride electrooxidation performance.Our synthesis involves the thermal transformation of a ZIF67-Co(OH)_(2)-rGO/NF precursor within a controlled temperature between 300 and 750℃,yielding distinct phase heterostructures and pristine Co and CoO,verified by X-ray diffraction(XRD)and transmission electron microscopy(TEM)analyses.Additionally,the Ultraviolet photoelectron spectroscopy and theoretical calculation result further validate the formation of the heterojunction and direction of electron transfer along the interface as well as the BH_(4)^(-)adsorption behavior across the heterointerface.Notably,the catalyst annealed at 600℃,designated Co-CoO@C-rGO/NF-600,exhibits an exceptional oxidation current density of 2.5 A cm^(-2)at 0 V vs.Ag/AgCl in an electrolyte containing 2 mol L^(-1)NaOH and 0.4 mol L^(-1)NaBH_(4)Furthermore,the Co-CoO@C-rGO/NF-600 catalyst demonstrates remarkable performance as the anode catalyst in a DBHPFC assembly,achieving a peak power density of 385.73 mW cm^(-2)and demonstrating the enduring operational stability.The superior electrocatalytic performance is primarily attributed to the synergistic effects of Co-CoO nanoparticles rich in active heterointerfaces and the superior electron mobility afforded by the rGO scaffold.These results not only deepen our understanding of anode catalyst design for DBHPFCs but also pave the way for breakthroughs in electrocatalytic technologies,driving forward the quest for sustainable energy solutions.展开更多
Ordered NiCo_(2)O_(4)/rGO nanowire arrays(NWAs)grown on a Ni foam substrate were synthesized using a template-free hydrothermal method and employed as an electrode with outstanding electrochemical properties for super...Ordered NiCo_(2)O_(4)/rGO nanowire arrays(NWAs)grown on a Ni foam substrate were synthesized using a template-free hydrothermal method and employed as an electrode with outstanding electrochemical properties for supercapacitors.After conducting a series of time-variable controlled experiments,the structure,morphology,and electrochemical properties of NiCo_(2)O_(4)/rGO NWAs were analyzed to find the most suitable growth time.Benefited from such unique array architectures,the designed NiCo_(2)O_(4)/rGO NWAs electrode demonstrates significant electrochemical properties,showing a specific capacitance of 2418 F·g^(-1)at a charge-discharge current density of 1 A·g^(-1).Moreover,it demonstrates exceptional stability,maintaining a capacity retention of 81.5%after undergoing 2,000 cycles,even when subjected to a current density of 10 A·g^(-1).The reason of high stability is that the spacing between the nanowire arrays is large and the diffusion resistance of the electrolyte is significantly reduced,which facilitates the diffusion of the electrolyte into the interior of the electrodes and establishes an effective contact with the surface of the nanowires.Furthermore,the NiCo_(2)O_(4)/rGO nanowire array grows directly on the Ni foam without binder,which establishes rapid electron transport pathways on the Ni foam substrate,resulting in excellent electrochemical properties.展开更多
In this paper,we present a novel approach to enhancing the visible light photodetection efficiency of reduced graphene oxide(rGO)by incorporating polypyrrole(Ppy)nanoparticles sized between 126 nm and 1025 nm.The rGO ...In this paper,we present a novel approach to enhancing the visible light photodetection efficiency of reduced graphene oxide(rGO)by incorporating polypyrrole(Ppy)nanoparticles sized between 126 nm and 1025 nm.The rGO and Ppy nanoparticles were synthesized via Hummer’s method and chemical polymerization,respectively.Characterization was performed using scanning electron microscope(SEM),transmission electron microscope(TEM),Raman spectroscopy,and optical measurements.The rGO/Ppy photodetector demonstrated a high photoresponsivity of 15 mA/W and a broad spectral response from 405 nm to 805 nm,indicating improved efficiency and versatility.This study high-lights the potential of tailored Ppy nanoparticle sizes in advancing rGO photodetectors for high-performance optoelectronic applications.展开更多
文摘首先以Hummers法制备还原态氧化石墨烯(RGO),其次通过溶胶-凝胶法和水热法分别制备TiO_(2)和TiO_(2)/RGO复合材料,然后向硝酸银溶液滴加氨水沉淀出纳米Ag并掺杂到TiO_(2)上,再以聚乙烯吡咯烷酮(PVP)为分散剂,以RGO为基体材料,用一步水热法合成Ag@TiO_(2)/RGO复合光催化剂。复合材料通过FT-IR、XRD、SEM、DRS和BET等进行结构、组成、形貌和孔径大小的表征。将Ag@TiO_(2)/RGO用来光催化降解罗丹明B(RhB)溶液,结果表明,0.020 g该催化剂对50 mL 5 mg/L的RhB溶液在pH值为5、室温条件下的降解效果最好;经6次循环利用后,降解率依然能达到80%。
基金the financial support from the National Natural Science Foundation of China(No.52225208 and 51802131)the Training Program for academic and technical leaders in major disciplines of Jiangxi Province-Young Talents(No.20212BCJ23021)the Natural Science Foundation of Jiangxi Province,China(No.20232BAB204020).
文摘1T-MoS_(2)nanosheets,with metallic conductivity and high capacity,hold great potential for lithium-ion capacitors(LICs),but suffer from sluggish reaction kinetics due to dense stacking.Herein,1T-MoS_(2)nanosheets with enlarged interlayer spacing,vertically bonded to reduced graphene oxide(rGO)(1T-MoS_(2)/rGO),were designed using a hydrothermal-assisted dispersion and intercalation strategy.The active nitrogen species derived from N,N-dimethylformamide(DMF)not only bridge the rGO and MoS_(2)through strong Mo-N-C bonds to promote the formation of dispersed MoS_(2)nanosheets,but also intercalate into the MoS_(2)structure,further enlarging the interlayer spacing.This unique structure synergistically enhances meso-and microscale mass transfer outside and inside of the few-layered nanosheets,significantly improving electrochemical reaction kinetics and reducing the kinetic mismatch between the anode and cathode.Consequently,the resulting 1T-MoS_(2)/rGO achieves a capacity of 500 mAh g^(-1)after 500 cycles at 5 A g^(-1)and a high rate performance of 587 mAh g^(-1)at a high rate of 10 A g^(-1).Moreover,the assembled 3D vertical 1T-MoS_(2)/rGO//AC LIC delivers a high energy density of 100.3 Wh kg^(-1)at a power density of1.0 kW kg^(-1),and long cycle stability with capacity retention as high as 91.02%after 5000 cycles at 2 A g^(-1).This work provides a generalizable strategy for engineering two-dimensional material-based electrodes,offering new insights into high-performance energy storage systems.
基金funded by the National Natural Science Foundation of China(No.52402106)the Natural Science Foundation of Heilongjiang Province Jointly Guided Project(No.LH2023B010)the Planning Project of Heilongjiang Province Education Department(No.LJYXL2022-036)。
文摘Direct borohydride hydrogen peroxide fuel cells(DBHPFCs)are emerging as a transformative technology for sustainable energy conversion.Despite their potential,their efficiency is largely hindered by the limitations of the anode catalyst.In response to this challenge,we have developed a novel series of Co-based heterojunction metal-organic framework(MOF)derivatives,supported on reduced graphene oxide(rGO)-modified nickel foam(NF),to enhance borohydride electrooxidation performance.Our synthesis involves the thermal transformation of a ZIF67-Co(OH)_(2)-rGO/NF precursor within a controlled temperature between 300 and 750℃,yielding distinct phase heterostructures and pristine Co and CoO,verified by X-ray diffraction(XRD)and transmission electron microscopy(TEM)analyses.Additionally,the Ultraviolet photoelectron spectroscopy and theoretical calculation result further validate the formation of the heterojunction and direction of electron transfer along the interface as well as the BH_(4)^(-)adsorption behavior across the heterointerface.Notably,the catalyst annealed at 600℃,designated Co-CoO@C-rGO/NF-600,exhibits an exceptional oxidation current density of 2.5 A cm^(-2)at 0 V vs.Ag/AgCl in an electrolyte containing 2 mol L^(-1)NaOH and 0.4 mol L^(-1)NaBH_(4)Furthermore,the Co-CoO@C-rGO/NF-600 catalyst demonstrates remarkable performance as the anode catalyst in a DBHPFC assembly,achieving a peak power density of 385.73 mW cm^(-2)and demonstrating the enduring operational stability.The superior electrocatalytic performance is primarily attributed to the synergistic effects of Co-CoO nanoparticles rich in active heterointerfaces and the superior electron mobility afforded by the rGO scaffold.These results not only deepen our understanding of anode catalyst design for DBHPFCs but also pave the way for breakthroughs in electrocatalytic technologies,driving forward the quest for sustainable energy solutions.
文摘Ordered NiCo_(2)O_(4)/rGO nanowire arrays(NWAs)grown on a Ni foam substrate were synthesized using a template-free hydrothermal method and employed as an electrode with outstanding electrochemical properties for supercapacitors.After conducting a series of time-variable controlled experiments,the structure,morphology,and electrochemical properties of NiCo_(2)O_(4)/rGO NWAs were analyzed to find the most suitable growth time.Benefited from such unique array architectures,the designed NiCo_(2)O_(4)/rGO NWAs electrode demonstrates significant electrochemical properties,showing a specific capacitance of 2418 F·g^(-1)at a charge-discharge current density of 1 A·g^(-1).Moreover,it demonstrates exceptional stability,maintaining a capacity retention of 81.5%after undergoing 2,000 cycles,even when subjected to a current density of 10 A·g^(-1).The reason of high stability is that the spacing between the nanowire arrays is large and the diffusion resistance of the electrolyte is significantly reduced,which facilitates the diffusion of the electrolyte into the interior of the electrodes and establishes an effective contact with the surface of the nanowires.Furthermore,the NiCo_(2)O_(4)/rGO nanowire array grows directly on the Ni foam without binder,which establishes rapid electron transport pathways on the Ni foam substrate,resulting in excellent electrochemical properties.
文摘In this paper,we present a novel approach to enhancing the visible light photodetection efficiency of reduced graphene oxide(rGO)by incorporating polypyrrole(Ppy)nanoparticles sized between 126 nm and 1025 nm.The rGO and Ppy nanoparticles were synthesized via Hummer’s method and chemical polymerization,respectively.Characterization was performed using scanning electron microscope(SEM),transmission electron microscope(TEM),Raman spectroscopy,and optical measurements.The rGO/Ppy photodetector demonstrated a high photoresponsivity of 15 mA/W and a broad spectral response from 405 nm to 805 nm,indicating improved efficiency and versatility.This study high-lights the potential of tailored Ppy nanoparticle sizes in advancing rGO photodetectors for high-performance optoelectronic applications.
