CdS nanoclusters were directly synthesized in aqueous solution by using mercaptoacetic acid as the stabilizer. The results of TEM(Transmission Electron Microscopy) and ED(Electron Diffraction) show that the structures...CdS nanoclusters were directly synthesized in aqueous solution by using mercaptoacetic acid as the stabilizer. The results of TEM(Transmission Electron Microscopy) and ED(Electron Diffraction) show that the structures and aggregations of the resulting CdS nanoclusters can be affected by the molar ratio of mercaptoacetic acid and Cd 2+ ion. When the ratio was high, the resulting nanoclusters were observed as densely packed layer structure on the template. When the ratio was low, the prepared CdS nanoclusters can not form highly aggregated structure. Fluorescence spectra of the CdS nanoclusters show a strong yellow fluorescence.展开更多
In this work, we present a new versatile strategy to prepare noble metal （Au, Ag and Cu） nanoclusters on TiO2 nanosheets in large scales with exposed （001） facets with controlled size, crystalline interface, and l...In this work, we present a new versatile strategy to prepare noble metal （Au, Ag and Cu） nanoclusters on TiO2 nanosheets in large scales with exposed （001） facets with controlled size, crystalline interface, and loading amount. By precise in situ calcination, the metal （M = Au, Ag, and Cu） nanocrystals with controllable size and better crystalline interface with the TiO2 support have been prepared. The potential application of the as-prepared Au, Ag, and Cu nanoclusters on TiO2 nanosheets as potential heterogeneous catalysts for organic synthesis, such as catalytic reduction of 4-nitrophenol to 4-aminophenol, has been demonstrated. After calcination, Au, Ag, and Cu nanocrystals were found to be proficient cocatalysts for photocatalytic H2 evolution, particularly the Au cocatalyst. Based on precise high-resolution transmission electron microscopy （HRTEM） and inductively coupled plasma optical emission spectrometry （ICP-OES） analyses, the flexible control of their size and loading amount as well as their intimate contact with the TiO2 nanosheet enhanced the photocatalytic H2 evolution activity and the sensitivity of the photocurrent response of the film. Furthermore, this aqueous-directed synthesis of metal nanoclusters on a support will generate further interest in the field of nanocatalysis.展开更多
We report a comprehensive theoretical investigation of the catalytic reaction mechanisms of propene epoxidation on gold nanoclusters using density functional theory （DFT）. We have shown that water acts as a catalyti...We report a comprehensive theoretical investigation of the catalytic reaction mechanisms of propene epoxidation on gold nanoclusters using density functional theory （DFT）. We have shown that water acts as a catalytic promoter for propene epoxidation on gold catalysts. Even without reducible supports, hydroperoxyl （OOH） and hydroxyl （OH） radicals are readily formed on small-size gold clusters from co-adsorbed H20 and 02, with energy barriers as low as 4-6 kcal/mol （1 cal = 4.186 J）. Propene epoxidation occurs easily through reactions between C3H6 and the weakened O-O bond of the OOH radicals on the surfaces of gold clusters.展开更多
Co-based metal-organic framework(MOF),a kind of porous crystal material composed of Co ions and organic linkers,is a common type of MOF.It not only has the intrinsic properties of MOF,such as structural diversity,func...Co-based metal-organic framework(MOF),a kind of porous crystal material composed of Co ions and organic linkers,is a common type of MOF.It not only has the intrinsic properties of MOF,such as structural diversity,functional adjustability,and high surface area,but more importantly,it contains Co metal species,which are considered by many reports to be active catalytic centers for many reactions.Meanwhile,metal catalysts always received wide and sustained attention.The combi-nation of the two types of catalysts can enhance the catalytic performance and achieve the"1+1>2"effect.In this review,we mainly overview the synthesis methods of Co-based MOF-derived metal catalysts from nano-to atom-level and their applications in the catalysis field in recent years and put forward our own views and prospects for this research direction.展开更多
For the first time, we are reporting a novel type of dual fluorescence temperaturesensitive DNA-templated silver nanocluster （AgNC） pair, which contains two pieces of single-stranded AgNC in proximity through hybrid...For the first time, we are reporting a novel type of dual fluorescence temperaturesensitive DNA-templated silver nanocluster （AgNC） pair, which contains two pieces of single-stranded AgNC in proximity through hybridization. Both the chameleon AgNC pairs, A-NCP and B-NCP, possess two bright fluorescence peaks that achieve sensitive variations corresponding to temperature change from 15 to 45 ℃. With the increase in temperature, one of the fluorescence emissions of A-NCP （A-FL570） increases, while the other （A-FL640） decreases. However, both the emissions of B-NCP （B-FL685 and B-FL620） decrease simultaneously. Therefore, A-NCP shows a remarkable fluorescence color variation from orange to yellow, while the fluorescence color of B-NCP changes from orange to colorless, with increase in temperature. Moreover, the temperature responding linear range of A-NCP can be regulated by adjusting the structures and sequences of assistant DNA templates. It is assumed that the two single-stranded segmental AgNCs are integrated together as they are assembled into AgNC pairs, leading to a dramatic variation in fluorescence properties. The temperature-sensitive phenomenon is due to the dehybridization-induced separation of two pieces of segmental AgNC, caused by temperature increase. The temperature-sensitive AgNC pairs have been successful in indicating the temperature of living cells, showing the potential for a new application of silver nanocluster as a nanothermometer with adjustable response range, bringing novel insight into the regulatory mechanism of AgNC fluorescence variation.展开更多
High-energy-density Li-S batteries are subjected to serious sulfur deactivation and short cycle lifetime caused by undesirable polysulfide shuttle effect and frantic lithium dendrite formation.In this work,a controlla...High-energy-density Li-S batteries are subjected to serious sulfur deactivation and short cycle lifetime caused by undesirable polysulfide shuttle effect and frantic lithium dendrite formation.In this work,a controllable cage-confinement strategy to fabricate molybdenum carbide(MoC)nanoclusters as a high-efficient sulfiphilic and lithiophilic regulator to mitigate the formidable issues of Li-S batteries is demonstrated.The sub-2 nm MoC nanoclusters not only guarantee robust chemisorption and fast electrocatalytic conversion of polysulfides to enhance the sulfur electrochemistry,but also homogenize Li^(+) flux to suppress the lithium dendrite growth.As a consequence,the MoC-modified separator endows the batteries with boosted reaction kinetics,promoted sulfur utilization,and improved cycling stability.A reversible capacity of 701 mAh·g^(−1) at a high rate of 5.0C and a small decay rate of 0.076%per cycle at 1.0C over 600 cycles are achieved.This study offers a rational route for design and synthesis of bifunctional nanoclusers with both sulfiphilicity and lithiophilicity for high-performance Li-S batteries.展开更多
The lack of effective charge transfer driving force and channel limits the electron directional migration in nanoclusters(NC)-based heterostructures,resulting in poor photocatalytic performance.Herein,a Z-scheme NC-ba...The lack of effective charge transfer driving force and channel limits the electron directional migration in nanoclusters(NC)-based heterostructures,resulting in poor photocatalytic performance.Herein,a Z-scheme NC-based heterojunction(Pt1Ag28-BTT/CoP,BTT=1,3,5-benzenetrithiol)with strong internal electric field is constructed via interfacial Co-S bond,which exhibits an absolutely superiority in photocatalytic performance with 24.89 mmol·h^(−1)·g−1 H_(2)production rate,25.77%apparent quantum yield at 420 nm,and~100%activity retention in stability,compared with Pt1Ag28-BDT/CoP(BDT=1,3-benzenedithiol),Ag29-BDT/CoP,and CoP.The enhanced catalytic performance is contributed by the dual modulation strategy of inner core and outer shell of NC,wherein,the center Pt single atom doping regulates the band structure of NC to match well with CoP,builds internal electric field,and then drives photogenerated electrons steering;the accurate surface S modification promotes the formation of Co-S atomic-precise interface channel for further high-efficient Z-scheme charge directional migration.This work opens a new avenue for designing NC-based heterojunction with matchable band structure and valid interfacial charge transfer.展开更多
We demonstrated gold nanoclusters as color tunable emissive light converters for the application of white light emitting diodes (WLEDs). A blue LED providing 460 nm to excite gold nanoclusters mixed with UV curable ma...We demonstrated gold nanoclusters as color tunable emissive light converters for the application of white light emitting diodes (WLEDs). A blue LED providing 460 nm to excite gold nanoclusters mixed with UV curable material generates broad bandwidth emission at the visible range. Increasing the amount of gold nanoclusters, the correlated color temperature of WLEDs tuned from cold white to warm white, and also results in the variation of color rendering index (CRI). The highest CRI in the experiment is 92.展开更多
Developing new approaches to fulfill the enantioseparation of nanocluster racemates and construct cluster-based nanomaterials with optical activity remains highly desired in cluster science,because it is an essential ...Developing new approaches to fulfill the enantioseparation of nanocluster racemates and construct cluster-based nanomaterials with optical activity remains highly desired in cluster science,because it is an essential prerequisite for fundamental research and extensive applications of these nanomaterials.We herein propose a strategy termed“active-site exposing and partly re-protecting”to trigger the symmetry breaking of highly symmetrical nanoclusters and to render cluster crystals optically active.The vertex PPh_(3)of the symmetrical Ag_(29)(SSR)_(12)(PPh_(3))_(4)(SSR=1,3-benzenedithiol)nanocluster was firstly dissociated in the presence of counterions with large steric hindrance,and then the exposed Ag active sites of the obtained Ag_(29)(SSR)_(12)nanocluster were partly re-protected by Ag^(+),yielding an Ag_(29)(SSR)_(12)-Ag_(2)nanocluster with a symmetry-breaking construction.Ag_(29)(SSR)_(12)-Ag_(2)followed a chiral crystallization mode,and its crystal displayed strong optical activity,derived from CD and CPL characterizations.Overall,this work presents a new approach(i.e.,active-site exposing and partly re-protecting)for the symmetry breaking of highly symmetrical nanoclusters,the enantioseparation of nanocluster racemates,and the achievement of highly optical activity.展开更多
文摘CdS nanoclusters were directly synthesized in aqueous solution by using mercaptoacetic acid as the stabilizer. The results of TEM(Transmission Electron Microscopy) and ED(Electron Diffraction) show that the structures and aggregations of the resulting CdS nanoclusters can be affected by the molar ratio of mercaptoacetic acid and Cd 2+ ion. When the ratio was high, the resulting nanoclusters were observed as densely packed layer structure on the template. When the ratio was low, the prepared CdS nanoclusters can not form highly aggregated structure. Fluorescence spectra of the CdS nanoclusters show a strong yellow fluorescence.
文摘In this work, we present a new versatile strategy to prepare noble metal （Au, Ag and Cu） nanoclusters on TiO2 nanosheets in large scales with exposed （001） facets with controlled size, crystalline interface, and loading amount. By precise in situ calcination, the metal （M = Au, Ag, and Cu） nanocrystals with controllable size and better crystalline interface with the TiO2 support have been prepared. The potential application of the as-prepared Au, Ag, and Cu nanoclusters on TiO2 nanosheets as potential heterogeneous catalysts for organic synthesis, such as catalytic reduction of 4-nitrophenol to 4-aminophenol, has been demonstrated. After calcination, Au, Ag, and Cu nanocrystals were found to be proficient cocatalysts for photocatalytic H2 evolution, particularly the Au cocatalyst. Based on precise high-resolution transmission electron microscopy （HRTEM） and inductively coupled plasma optical emission spectrometry （ICP-OES） analyses, the flexible control of their size and loading amount as well as their intimate contact with the TiO2 nanosheet enhanced the photocatalytic H2 evolution activity and the sensitivity of the photocurrent response of the film. Furthermore, this aqueous-directed synthesis of metal nanoclusters on a support will generate further interest in the field of nanocatalysis.
文摘We report a comprehensive theoretical investigation of the catalytic reaction mechanisms of propene epoxidation on gold nanoclusters using density functional theory （DFT）. We have shown that water acts as a catalytic promoter for propene epoxidation on gold catalysts. Even without reducible supports, hydroperoxyl （OOH） and hydroxyl （OH） radicals are readily formed on small-size gold clusters from co-adsorbed H20 and 02, with energy barriers as low as 4-6 kcal/mol （1 cal = 4.186 J）. Propene epoxidation occurs easily through reactions between C3H6 and the weakened O-O bond of the OOH radicals on the surfaces of gold clusters.
基金The authors gratefully acknowledge the financial support from the Natural Science research project of Universities in Anhui Province(KJ2021ZD0001)the Natural Science Foundation of AnhuiProvince(2208085MB20).
文摘Co-based metal-organic framework(MOF),a kind of porous crystal material composed of Co ions and organic linkers,is a common type of MOF.It not only has the intrinsic properties of MOF,such as structural diversity,functional adjustability,and high surface area,but more importantly,it contains Co metal species,which are considered by many reports to be active catalytic centers for many reactions.Meanwhile,metal catalysts always received wide and sustained attention.The combi-nation of the two types of catalysts can enhance the catalytic performance and achieve the"1+1>2"effect.In this review,we mainly overview the synthesis methods of Co-based MOF-derived metal catalysts from nano-to atom-level and their applications in the catalysis field in recent years and put forward our own views and prospects for this research direction.
基金This work was supported by National Natural Science Foundation of China （No. 21375123） and The Ministry of Science and Technology of China （No. 216YFA0203201）.
文摘For the first time, we are reporting a novel type of dual fluorescence temperaturesensitive DNA-templated silver nanocluster （AgNC） pair, which contains two pieces of single-stranded AgNC in proximity through hybridization. Both the chameleon AgNC pairs, A-NCP and B-NCP, possess two bright fluorescence peaks that achieve sensitive variations corresponding to temperature change from 15 to 45 ℃. With the increase in temperature, one of the fluorescence emissions of A-NCP （A-FL570） increases, while the other （A-FL640） decreases. However, both the emissions of B-NCP （B-FL685 and B-FL620） decrease simultaneously. Therefore, A-NCP shows a remarkable fluorescence color variation from orange to yellow, while the fluorescence color of B-NCP changes from orange to colorless, with increase in temperature. Moreover, the temperature responding linear range of A-NCP can be regulated by adjusting the structures and sequences of assistant DNA templates. It is assumed that the two single-stranded segmental AgNCs are integrated together as they are assembled into AgNC pairs, leading to a dramatic variation in fluorescence properties. The temperature-sensitive phenomenon is due to the dehybridization-induced separation of two pieces of segmental AgNC, caused by temperature increase. The temperature-sensitive AgNC pairs have been successful in indicating the temperature of living cells, showing the potential for a new application of silver nanocluster as a nanothermometer with adjustable response range, bringing novel insight into the regulatory mechanism of AgNC fluorescence variation.
基金This study was financially supported by the research funds from the National Natural Science Foundation of China(No.52272239)the Fundamental Research Funds for the Central Universities(Nos.D5000210894 and 3102019JC005)the Analytical&Testing Center of Northwestern Polytechnical University for TEM analysis.
文摘High-energy-density Li-S batteries are subjected to serious sulfur deactivation and short cycle lifetime caused by undesirable polysulfide shuttle effect and frantic lithium dendrite formation.In this work,a controllable cage-confinement strategy to fabricate molybdenum carbide(MoC)nanoclusters as a high-efficient sulfiphilic and lithiophilic regulator to mitigate the formidable issues of Li-S batteries is demonstrated.The sub-2 nm MoC nanoclusters not only guarantee robust chemisorption and fast electrocatalytic conversion of polysulfides to enhance the sulfur electrochemistry,but also homogenize Li^(+) flux to suppress the lithium dendrite growth.As a consequence,the MoC-modified separator endows the batteries with boosted reaction kinetics,promoted sulfur utilization,and improved cycling stability.A reversible capacity of 701 mAh·g^(−1) at a high rate of 5.0C and a small decay rate of 0.076%per cycle at 1.0C over 600 cycles are achieved.This study offers a rational route for design and synthesis of bifunctional nanoclusers with both sulfiphilicity and lithiophilicity for high-performance Li-S batteries.
基金the Natural Science research project of Universities in Anhui Province(No.KJ2021ZD0001)the Natural Science Foundation of Anhui Province(No.2208085MB20)the National Natural Science Foundation of China(No.22101001).
文摘The lack of effective charge transfer driving force and channel limits the electron directional migration in nanoclusters(NC)-based heterostructures,resulting in poor photocatalytic performance.Herein,a Z-scheme NC-based heterojunction(Pt1Ag28-BTT/CoP,BTT=1,3,5-benzenetrithiol)with strong internal electric field is constructed via interfacial Co-S bond,which exhibits an absolutely superiority in photocatalytic performance with 24.89 mmol·h^(−1)·g−1 H_(2)production rate,25.77%apparent quantum yield at 420 nm,and~100%activity retention in stability,compared with Pt1Ag28-BDT/CoP(BDT=1,3-benzenedithiol),Ag29-BDT/CoP,and CoP.The enhanced catalytic performance is contributed by the dual modulation strategy of inner core and outer shell of NC,wherein,the center Pt single atom doping regulates the band structure of NC to match well with CoP,builds internal electric field,and then drives photogenerated electrons steering;the accurate surface S modification promotes the formation of Co-S atomic-precise interface channel for further high-efficient Z-scheme charge directional migration.This work opens a new avenue for designing NC-based heterojunction with matchable band structure and valid interfacial charge transfer.
文摘We demonstrated gold nanoclusters as color tunable emissive light converters for the application of white light emitting diodes (WLEDs). A blue LED providing 460 nm to excite gold nanoclusters mixed with UV curable material generates broad bandwidth emission at the visible range. Increasing the amount of gold nanoclusters, the correlated color temperature of WLEDs tuned from cold white to warm white, and also results in the variation of color rendering index (CRI). The highest CRI in the experiment is 92.
基金We acknowledge the financial support of the NSFC(21631001,21871001,and 22101001)the Ministry of Education,and the University Synergy Innovation Program of Anhui Province(GXXT-2020-053).
文摘Developing new approaches to fulfill the enantioseparation of nanocluster racemates and construct cluster-based nanomaterials with optical activity remains highly desired in cluster science,because it is an essential prerequisite for fundamental research and extensive applications of these nanomaterials.We herein propose a strategy termed“active-site exposing and partly re-protecting”to trigger the symmetry breaking of highly symmetrical nanoclusters and to render cluster crystals optically active.The vertex PPh_(3)of the symmetrical Ag_(29)(SSR)_(12)(PPh_(3))_(4)(SSR=1,3-benzenedithiol)nanocluster was firstly dissociated in the presence of counterions with large steric hindrance,and then the exposed Ag active sites of the obtained Ag_(29)(SSR)_(12)nanocluster were partly re-protected by Ag^(+),yielding an Ag_(29)(SSR)_(12)-Ag_(2)nanocluster with a symmetry-breaking construction.Ag_(29)(SSR)_(12)-Ag_(2)followed a chiral crystallization mode,and its crystal displayed strong optical activity,derived from CD and CPL characterizations.Overall,this work presents a new approach(i.e.,active-site exposing and partly re-protecting)for the symmetry breaking of highly symmetrical nanoclusters,the enantioseparation of nanocluster racemates,and the achievement of highly optical activity.
