Luminescent nanoclusters(NCs)have attracted much attention because of their superior photophysical properties;however,the design of dynamic NCs with reversible structural change is highly challenging.Herein,we synthes...Luminescent nanoclusters(NCs)have attracted much attention because of their superior photophysical properties;however,the design of dynamic NCs with reversible structural change is highly challenging.Herein,we synthesize a kind of dynamic luminescent NCs through Schiff base crosslinking between triethylenetetramine(TETA)and tannic acid at room temperature.The proposed NCs have an excitation-independent blue emission,and the maximum emission is available at about 458 nm with two excitation centers.Furthermore,the crosslinking degree of the NCs can be effectively adjusted by TETA and their formation is a kineticcontrol process.Most importantly,the proposed NCs show a property of pHcontrolled reversible depolymerization and polymerization,accompanied by a cyclic“on-off-on”photoswitching,which is directly attributed to pH-stimulated reversible C=N bond cleavage and re-formation.Because of the reversible structure change properties,the dynamic NCs have been well used in reversible information encryption.This new finding provides not only us with a powerful strategy to study the structure–properties relationship of luminescent NCs but also a design idea for constructing smart optical nanomaterials.展开更多
Cu nanoparticles with different sizes,morphology,and surface structures exhibit distinct activity and selectivity toward CO_(2) reduction reaction,while the reactive sites and reaction mechanisms are very controversia...Cu nanoparticles with different sizes,morphology,and surface structures exhibit distinct activity and selectivity toward CO_(2) reduction reaction,while the reactive sites and reaction mechanisms are very controversial in experiments.In this study,we demonstrate the dynamic structure change of Cu clusters on graphite-like carbon supports plays an important role in the multicarbon production by combining static calculations and ab-initio molecular dynamic simulations.The mobility of Cu clusters on graphite is attributed to the near-degenerate energies of various adsorption configurations,as the interaction between Cu atoms and surface C atoms is weaker than that of Cu-Cu bonds in the tight cluster form.Such structure change of Cu clusters leads to step-like irregular surface structures and appropriate interparticle distances,increasing the selectivity of multicarbon products by reducing the energy barriers of C-C coupling effectively.In contrast,the large ratio of edge and corner sites on Cu clusters is responsible for the increased catalytic activity and selectivity for CO and H_(2) compared with Cu(100)surface,instead of hydrocarbon products like methane and ethylene.The detailed study reveals that the dynamic structure change of the catalysts results in roughened surface morphologies during catalytic reactions and plays an essential role in the selectivity of CO_(2) electro-reduction,which should be paid more attention for studies on the reaction mechanisms.展开更多
Supported metal catalysts are essential for industrial processes like energy conversion,chemical synthesis,and pollutant removal,yet they often suffer from low activity,poor selectivity,and deactivation.Matching zeoli...Supported metal catalysts are essential for industrial processes like energy conversion,chemical synthesis,and pollutant removal,yet they often suffer from low activity,poor selectivity,and deactivation.Matching zeolites with metal species is an effective method for synthesizing highly efficient heterogeneous catalysts,where the zeolite crystals not only stabilize the metal species against sintering/leaching,but also enhance the catalytic activity and product selectivity.In this minireview,we briefly summarize recent advances in matching zeolites with metal species for efficient catalysis,highlighting the synergistic effects between zeolites and metal species to improve the catalytic performance.Multiple functions of zeolites with respect to the metal species are highlighted,including the regulation of reactant/product diffusion for increasing the catalytic activity,the control of steric adsorption of reactant for changing the product selectivity,and the modulation of dynamic structural change of metal species for enhancing catalytic stability.Additionally,future challenges and opportunities in rational metal-zeolite catalyst design are discussed to inspire further innovations in catalytic applications.We believe that this minireviewwill open up novel pathways for the widespread utilization of metal-zeolite catalysts in diverse catalytic processes.展开更多
基金supported by the National Natural Science Foundation of China(52273197 and 52333007)Shenzhen Key Laboratory of Functional Aggregate Materials(ZDSYS20211021111400001)+2 种基金the Science and Technology Plan of Shenzhen(JCYJ2021324134613038,JCYJ20220818103007014,KQTD20210811090142053,GJHZ20210705141810031)the Innovation and Technology Commission(ITC-CNERC14SC01)Tianjin Key Medical Discipline(Specialty)Construction Project.
文摘Luminescent nanoclusters(NCs)have attracted much attention because of their superior photophysical properties;however,the design of dynamic NCs with reversible structural change is highly challenging.Herein,we synthesize a kind of dynamic luminescent NCs through Schiff base crosslinking between triethylenetetramine(TETA)and tannic acid at room temperature.The proposed NCs have an excitation-independent blue emission,and the maximum emission is available at about 458 nm with two excitation centers.Furthermore,the crosslinking degree of the NCs can be effectively adjusted by TETA and their formation is a kineticcontrol process.Most importantly,the proposed NCs show a property of pHcontrolled reversible depolymerization and polymerization,accompanied by a cyclic“on-off-on”photoswitching,which is directly attributed to pH-stimulated reversible C=N bond cleavage and re-formation.Because of the reversible structure change properties,the dynamic NCs have been well used in reversible information encryption.This new finding provides not only us with a powerful strategy to study the structure–properties relationship of luminescent NCs but also a design idea for constructing smart optical nanomaterials.
基金National Natural Science Foundation of China,Grant/Award Numbers:22033002,21525311,21703032Fundamental Research Funds for the Central Universities of China。
文摘Cu nanoparticles with different sizes,morphology,and surface structures exhibit distinct activity and selectivity toward CO_(2) reduction reaction,while the reactive sites and reaction mechanisms are very controversial in experiments.In this study,we demonstrate the dynamic structure change of Cu clusters on graphite-like carbon supports plays an important role in the multicarbon production by combining static calculations and ab-initio molecular dynamic simulations.The mobility of Cu clusters on graphite is attributed to the near-degenerate energies of various adsorption configurations,as the interaction between Cu atoms and surface C atoms is weaker than that of Cu-Cu bonds in the tight cluster form.Such structure change of Cu clusters leads to step-like irregular surface structures and appropriate interparticle distances,increasing the selectivity of multicarbon products by reducing the energy barriers of C-C coupling effectively.In contrast,the large ratio of edge and corner sites on Cu clusters is responsible for the increased catalytic activity and selectivity for CO and H_(2) compared with Cu(100)surface,instead of hydrocarbon products like methane and ethylene.The detailed study reveals that the dynamic structure change of the catalysts results in roughened surface morphologies during catalytic reactions and plays an essential role in the selectivity of CO_(2) electro-reduction,which should be paid more attention for studies on the reaction mechanisms.
基金support of the Zhejiang Provincial Basic Public Welfare Project(grant no.LD24E030003)the National Natural Science Foundation of China(grant nos.U21B20101 and 22202175).
文摘Supported metal catalysts are essential for industrial processes like energy conversion,chemical synthesis,and pollutant removal,yet they often suffer from low activity,poor selectivity,and deactivation.Matching zeolites with metal species is an effective method for synthesizing highly efficient heterogeneous catalysts,where the zeolite crystals not only stabilize the metal species against sintering/leaching,but also enhance the catalytic activity and product selectivity.In this minireview,we briefly summarize recent advances in matching zeolites with metal species for efficient catalysis,highlighting the synergistic effects between zeolites and metal species to improve the catalytic performance.Multiple functions of zeolites with respect to the metal species are highlighted,including the regulation of reactant/product diffusion for increasing the catalytic activity,the control of steric adsorption of reactant for changing the product selectivity,and the modulation of dynamic structural change of metal species for enhancing catalytic stability.Additionally,future challenges and opportunities in rational metal-zeolite catalyst design are discussed to inspire further innovations in catalytic applications.We believe that this minireviewwill open up novel pathways for the widespread utilization of metal-zeolite catalysts in diverse catalytic processes.
