Because of the low reactivity of cyclic nitrides,liquid-phase synthesis of carbon nitride introduces challenges despite its favorable potential for energy-efficient preparation and superior applications.In this study,...Because of the low reactivity of cyclic nitrides,liquid-phase synthesis of carbon nitride introduces challenges despite its favorable potential for energy-efficient preparation and superior applications.In this study,we demonstrate a strong interaction between citric acid and melamine through experimental observation and theoretical simulation,which eff ectively activates melamine-condensation activity and produces carbon-rich carbon nitride nanosheets(CCN NSs)during hydrothermal reaction.Under a large specific surface area and increased light absorption,these CCN NSs demonstrate significantly enhanced photocatalytic activity in CO_(2) reduction,increasing the CO production rate by approximately tenfold compared with hexagonal melamine(h-Me).Moreover,the product selectivity of CCN NSs reaches up to 93.5%to generate CO from CO_(2).Furthermore,the annealed CCN NSs exhibit a CO conversion rate of up to 95.30μmol/(g h),which indicates an 18-fold increase compared with traditional carbon nitride.During the CCN NS synthesis,nitrogen-doped carbon quantum dots(NDC QDs)are simultaneously produced and remain suspended in the supernatant after centrifugation.These QDs disperse well in water and exhibit excellent luminescent properties(QY=67.2%),allowing their application in the design of selective and sensitive sensors to detect pollutants such as pesticide 2,4-dichlorophenol with a detection limit of as low as 0.04μmol/L.Notably,the simultaneous synthesis of CCN NSs and NDC QDs provides a cost-eff ective and highly efficient process,yielding products with superior capabilities for catalytic conversion of CO_(2) and pollutant detection,respectively.展开更多
The impact of the size effect on the color and photoluminescence(PL)of quantum dots(QDs)has sparked a revolutionary field of research,culminating in the prestigious Nobel Prize in 2023.Prior to their widespread popula...The impact of the size effect on the color and photoluminescence(PL)of quantum dots(QDs)has sparked a revolutionary field of research,culminating in the prestigious Nobel Prize in 2023.Prior to their widespread popularization and large-scale commercialization,it is of paramount importance to effectively manipulate and optimize their optical properties.In this review,we place specific emphasis on the striking correlation between the optical characteristics of QDs and their size,structure,composition,and interface environment.We commence by tracing the evolution of quantum dot technology and subsequently categorizing QDs while outlining their typical synthesis methods.This is followed by a deep dive into the pivotal roles of size,composition,structure,and interfacial ligands in fine-tuning,optimizing,and enhancing the optical properties of QDs.Additionally,we illustrate the luminescence enhancement and charge transfer phenomena stemming from the heterojunction between semiconductor QDs and metal nanomaterials,which contribute to improved performance.Lastly,we introduce the burgeoning field of chiral QDs and their innovative applications.Armed with this knowledge,QDs can be readily tailored to exhibit adjustable luminous characteristics across the entire spectrum,boasting high luminous efficiency through multifaceted regulation.These advancements render QDs even more enticing and promising for a wide array of applications.展开更多
基金supported by the National High Technology Research and Development Program of China(No.2021YFF1200200)the Peiyang Talents Project of Tianjin University。
文摘Because of the low reactivity of cyclic nitrides,liquid-phase synthesis of carbon nitride introduces challenges despite its favorable potential for energy-efficient preparation and superior applications.In this study,we demonstrate a strong interaction between citric acid and melamine through experimental observation and theoretical simulation,which eff ectively activates melamine-condensation activity and produces carbon-rich carbon nitride nanosheets(CCN NSs)during hydrothermal reaction.Under a large specific surface area and increased light absorption,these CCN NSs demonstrate significantly enhanced photocatalytic activity in CO_(2) reduction,increasing the CO production rate by approximately tenfold compared with hexagonal melamine(h-Me).Moreover,the product selectivity of CCN NSs reaches up to 93.5%to generate CO from CO_(2).Furthermore,the annealed CCN NSs exhibit a CO conversion rate of up to 95.30μmol/(g h),which indicates an 18-fold increase compared with traditional carbon nitride.During the CCN NS synthesis,nitrogen-doped carbon quantum dots(NDC QDs)are simultaneously produced and remain suspended in the supernatant after centrifugation.These QDs disperse well in water and exhibit excellent luminescent properties(QY=67.2%),allowing their application in the design of selective and sensitive sensors to detect pollutants such as pesticide 2,4-dichlorophenol with a detection limit of as low as 0.04μmol/L.Notably,the simultaneous synthesis of CCN NSs and NDC QDs provides a cost-eff ective and highly efficient process,yielding products with superior capabilities for catalytic conversion of CO_(2) and pollutant detection,respectively.
基金supported by the National High Technology Research and Development Program of China(No.2021YFF1200200)the Peiyang Talents Project of Tianjin University.
文摘The impact of the size effect on the color and photoluminescence(PL)of quantum dots(QDs)has sparked a revolutionary field of research,culminating in the prestigious Nobel Prize in 2023.Prior to their widespread popularization and large-scale commercialization,it is of paramount importance to effectively manipulate and optimize their optical properties.In this review,we place specific emphasis on the striking correlation between the optical characteristics of QDs and their size,structure,composition,and interface environment.We commence by tracing the evolution of quantum dot technology and subsequently categorizing QDs while outlining their typical synthesis methods.This is followed by a deep dive into the pivotal roles of size,composition,structure,and interfacial ligands in fine-tuning,optimizing,and enhancing the optical properties of QDs.Additionally,we illustrate the luminescence enhancement and charge transfer phenomena stemming from the heterojunction between semiconductor QDs and metal nanomaterials,which contribute to improved performance.Lastly,we introduce the burgeoning field of chiral QDs and their innovative applications.Armed with this knowledge,QDs can be readily tailored to exhibit adjustable luminous characteristics across the entire spectrum,boasting high luminous efficiency through multifaceted regulation.These advancements render QDs even more enticing and promising for a wide array of applications.
