Ligand-passivated metal nanoclusters with both high stability and catalytic activity have been pursued for a long time to shed light on the underlying rationale of ligand-functionalized metal nanocatalysts in chemical...Ligand-passivated metal nanoclusters with both high stability and catalytic activity have been pursued for a long time to shed light on the underlying rationale of ligand-functionalized metal nanocatalysts in chemical transformations.Nevertheless,these atomically precise nanocatalysts often exhibit low catalytic activity due to the extensive coverage of active sites.In this work,we report a robust gold-copper alloy nanocluster with 74 nuclei with high catalytic performance.展开更多
Unconventional natural gas has become an important supplement to conventional energy sources,and the process of enrichment and purification of methane from low concentration coalbed methane is crucial.To this end,we r...Unconventional natural gas has become an important supplement to conventional energy sources,and the process of enrichment and purification of methane from low concentration coalbed methane is crucial.To this end,we report a copper-based metal-organic framework(MOF),ZJNU-119Cu,featuring two methane traps constructed with uncoordinated carboxylic acid oxygens and open metal sites.ZJNU-119Cu exhibits a high methane adsorption capacity(58.2 cm^(3)·g^(-1))at 298 K and 0.1 MPa and excellent CH_(4)/N_(2) separation performance under dynamic conditions.Densityfunctional theory calculations combined with grand canonical Monte Carlo simulation theory reveal the interaction mechanism for the uncoordinated carboxylic acid oxygen atoms and open metal sites in ZJNU-119Cu with CH4.The gas adsorption isotherms,heat of adsorption calculations,and breakthrough separation experiments indicate that this MOF is a very promising adsorbent for CH_(4)/N_(2) separation.展开更多
Unsourced multiple access(UMA)is a multi-access technology for massive,low-power,uncoordinated,and unsourced Machine Type Communication(MTC)networks.It ensures transmission reliability under the premise of high energy...Unsourced multiple access(UMA)is a multi-access technology for massive,low-power,uncoordinated,and unsourced Machine Type Communication(MTC)networks.It ensures transmission reliability under the premise of high energy efficiency.Based on the analysis of the 6G MTC key performance indicators(KPIs)and scenario characteristics,this paper summarizes its requirements for radio access networks.Following this,the existing multiple access models are analyzed under these standards to determine UMA's advantages for 6G MTC according to its design characteristics.The critical technology of UMA is the design of its multiple-access coding scheme.Therefore,the existing UMA coding schemes from different coding paradigms are further summarized and compared.In particular,this paper comprehensively considers the energy efficiency and computational complexity of these schemes,studies the changes of the above two indexes with the increase of access scale,and considers the trade-off between the two.It is revealed by the above analysis that some guiding rules of UMA coding design.Finally,the open problems and potentials in this field are given for future research.展开更多
Group 5 and 6 metal chlorides,MCl_(x)(M=Nb,Ta,Mo,W)are easily and controllably reduced,in a stepwise fashion,by stoichiometric PhMe_(2)SiH,yielding only PhMe_(2)SiCl,a useful reagent,and H2 as the byproducts.Addition ...Group 5 and 6 metal chlorides,MCl_(x)(M=Nb,Ta,Mo,W)are easily and controllably reduced,in a stepwise fashion,by stoichiometric PhMe_(2)SiH,yielding only PhMe_(2)SiCl,a useful reagent,and H2 as the byproducts.Addition of n moles of PhMe_(2)SiH to toluene solutions of MCl_(x)yields stepwise uncoordinated reduction products of the form MCl_(x-n)(M=Nb,Ta,Mo,W;x=5 for Nb,Ta,Mo,x=6 for W;n=1 for Nb and Ta,n=1,2 for Mo and W).展开更多
Bimetallic MOFs show a synergistic effect and enhanced properties compared to their monometallic counterparts;however,the topologies and functions of bimetallic MOFs are difficult to predict or control.Here,a 3D metal...Bimetallic MOFs show a synergistic effect and enhanced properties compared to their monometallic counterparts;however,the topologies and functions of bimetallic MOFs are difficult to predict or control.Here,a 3D metal-organic framework(MOF),Tb-HODA,with an uncoordinated carboxyl group inner pore has been constructed,which exhibits good chemical resistance to both acidic and alkaline solutions with pH ranging from 2.5 to 12.5.Owing to the use of uncoordinated carboxyl groups within the channel as potential coordination sites for metal ions,this stable MOF exhibits a high sensitivity(KSV=5.12×10^(4) L mol^(-1))and a low detection limit(1.28 ppb)for sensing Fe^(2+)ions in aqueous solution,as well as a strong adsorption of Fe^(2+)with a potential to be a long-acting toxicide.Notably,the Lewis acidic property considerably increases when Tb-HODA adsorbs Fe^(2+)(Tb-HODA.Fe^(2+)),which makes Tb-HODA.Fe^(2+)exhibit highly efficient and selective solid acid catalysis for the dehydration of fructose/glucose into 5-hydroxymethylfurfural.展开更多
An anionic hydrogen-bonded organic framework(HOF)(named DBDA)is formed by the solvothermal reaction of squaramide-based tetracarboxylic acid organic building units(OBUs).Thanks to the diketone uncoordinated units in t...An anionic hydrogen-bonded organic framework(HOF)(named DBDA)is formed by the solvothermal reaction of squaramide-based tetracarboxylic acid organic building units(OBUs).Thanks to the diketone uncoordinated units in the squaramide functionalized groups and anionic frameworks of DBDA.展开更多
基金support from the Program for Young Talents of Science and Technology in the Universities of Inner Mongolia Autonomous Region(NJYT23035)the start-up funding of Inner Mongolia University(10000-23112101/043)+7 种基金F.L.expresses gratitude for the financial support from the National Natural Science Foundation of China(11964024)the“Grassland Talents”project of the Inner Mongolia Autonomous Region(12000-12102613)the Young Science and Technology Talents Cultivation Project of Inner Mongolia University(21200-5223708)S.G.acknowledges the financial support by the Program for Young Talents of Science and Technology in the Universities of Inner Mongolia Autonomous Region(NJYT22091)the Natural Science Foundation of Inner Mongolia Autonomous Region of China(2021BS02002)the Young Science and Technology Talents Cultivation Project of Inner Mongolia University(No.21221505)Y.J.acknowledges the financial support from the Natural Science Foundation of Inner Mongolia Autonomous Region of China(2022QN02015)the Research Program of Science and Technology at the Universities of Inner Mongolia Autonomous Region(NJZY22334).
文摘Ligand-passivated metal nanoclusters with both high stability and catalytic activity have been pursued for a long time to shed light on the underlying rationale of ligand-functionalized metal nanocatalysts in chemical transformations.Nevertheless,these atomically precise nanocatalysts often exhibit low catalytic activity due to the extensive coverage of active sites.In this work,we report a robust gold-copper alloy nanocluster with 74 nuclei with high catalytic performance.
基金financial support from the National Natural Science Foundation of China(22408258 and 22378287)the Joint Founds of the National Natural Science Foundation of China(U20B6004)the Natural Science Foundation of Shanxi Province(202303021222012).
文摘Unconventional natural gas has become an important supplement to conventional energy sources,and the process of enrichment and purification of methane from low concentration coalbed methane is crucial.To this end,we report a copper-based metal-organic framework(MOF),ZJNU-119Cu,featuring two methane traps constructed with uncoordinated carboxylic acid oxygens and open metal sites.ZJNU-119Cu exhibits a high methane adsorption capacity(58.2 cm^(3)·g^(-1))at 298 K and 0.1 MPa and excellent CH_(4)/N_(2) separation performance under dynamic conditions.Densityfunctional theory calculations combined with grand canonical Monte Carlo simulation theory reveal the interaction mechanism for the uncoordinated carboxylic acid oxygen atoms and open metal sites in ZJNU-119Cu with CH4.The gas adsorption isotherms,heat of adsorption calculations,and breakthrough separation experiments indicate that this MOF is a very promising adsorbent for CH_(4)/N_(2) separation.
基金supported by National Natural Science Foundation of China under Grant 61971062,Grant 92067202,Grant 62071058,Grant 62001049Beijing Natural Science Foundation under Grant 4222012Beijing University of Posts and Telecommunications China Mobile Research Institute Joint Innovation Center。
文摘Unsourced multiple access(UMA)is a multi-access technology for massive,low-power,uncoordinated,and unsourced Machine Type Communication(MTC)networks.It ensures transmission reliability under the premise of high energy efficiency.Based on the analysis of the 6G MTC key performance indicators(KPIs)and scenario characteristics,this paper summarizes its requirements for radio access networks.Following this,the existing multiple access models are analyzed under these standards to determine UMA's advantages for 6G MTC according to its design characteristics.The critical technology of UMA is the design of its multiple-access coding scheme.Therefore,the existing UMA coding schemes from different coding paradigms are further summarized and compared.In particular,this paper comprehensively considers the energy efficiency and computational complexity of these schemes,studies the changes of the above two indexes with the increase of access scale,and considers the trade-off between the two.It is revealed by the above analysis that some guiding rules of UMA coding design.Finally,the open problems and potentials in this field are given for future research.
基金supported by the Department of Chemistry,College of Sciences,and the Faculty Cluster Initiative at the University of Central Florida.The use of the IMSERC Crystallography facility at Northwestern Universitysupport from the Soft and Hybrid Nanotechnology Experimental(SHyNE)Resource(NSF ECCS-2025633)Northwestern University,is gratefully acknowledged.
文摘Group 5 and 6 metal chlorides,MCl_(x)(M=Nb,Ta,Mo,W)are easily and controllably reduced,in a stepwise fashion,by stoichiometric PhMe_(2)SiH,yielding only PhMe_(2)SiCl,a useful reagent,and H2 as the byproducts.Addition of n moles of PhMe_(2)SiH to toluene solutions of MCl_(x)yields stepwise uncoordinated reduction products of the form MCl_(x-n)(M=Nb,Ta,Mo,W;x=5 for Nb,Ta,Mo,x=6 for W;n=1 for Nb and Ta,n=1,2 for Mo and W).
基金supported by the Natural Science Foundation of Jiangsu Province for Outstanding Youth(No.BK20180105)the Top-notch Academic Programs Project of Jiangsu Higher Education Institutions(TAPP),and the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX20_2353,KYCX20_2240).
文摘Bimetallic MOFs show a synergistic effect and enhanced properties compared to their monometallic counterparts;however,the topologies and functions of bimetallic MOFs are difficult to predict or control.Here,a 3D metal-organic framework(MOF),Tb-HODA,with an uncoordinated carboxyl group inner pore has been constructed,which exhibits good chemical resistance to both acidic and alkaline solutions with pH ranging from 2.5 to 12.5.Owing to the use of uncoordinated carboxyl groups within the channel as potential coordination sites for metal ions,this stable MOF exhibits a high sensitivity(KSV=5.12×10^(4) L mol^(-1))and a low detection limit(1.28 ppb)for sensing Fe^(2+)ions in aqueous solution,as well as a strong adsorption of Fe^(2+)with a potential to be a long-acting toxicide.Notably,the Lewis acidic property considerably increases when Tb-HODA adsorbs Fe^(2+)(Tb-HODA.Fe^(2+)),which makes Tb-HODA.Fe^(2+)exhibit highly efficient and selective solid acid catalysis for the dehydration of fructose/glucose into 5-hydroxymethylfurfural.
基金financial support from the Major Basic Research Project of the Natural Science Foundation of Jiangsu Higher Education Institutions(No.21KJA150001)the Natural Science Foundation of Jiangsu Province for Outstanding Youth(No.BK20180105)TAPP of Jiangsu Higher Education Institutions,and the Postgraduate Research&Practice Innovation Program of Jiangsu Normal University.
文摘An anionic hydrogen-bonded organic framework(HOF)(named DBDA)is formed by the solvothermal reaction of squaramide-based tetracarboxylic acid organic building units(OBUs).Thanks to the diketone uncoordinated units in the squaramide functionalized groups and anionic frameworks of DBDA.
