Ensuring high electrocatalytic performance simultaneously with low or even no precious-metal usage is still a big challenge for the development of electrocatalysts toward oxygen evolution reaction(OER)in anion exchang...Ensuring high electrocatalytic performance simultaneously with low or even no precious-metal usage is still a big challenge for the development of electrocatalysts toward oxygen evolution reaction(OER)in anion exchange membrane water electrolysis.Here,homogeneous high entropy oxide(HEO)film is in-situ fabricated on nickel foam(NF)substrate via magnetron sputtering technology without annealing process in air,which is composed of many spinel-structured(FeCoNiCrMo)_(3)O_(4) grains with an average particle size of 2.5 nm.The resulting HEO film(abbreviated as(FeCoNiCr-Mo)_(3)O_(4))exhibits a superior OER performance with a low OER overpotential of 216 mV at 10 mA cm^(–2) and steadily operates at 100 mA cm^(–2) for 200 h with a decay of only 272μV h^(–1),which is far better than that of commercial IrO_(2) catalyst(290 mV,1090μV h^(–1)).Tetramethylammonium cation(TMA^(+))probe experiment,activation energy analysis and theoretical calculations unveil that the OER on(FeCoNiCrMo)_(3)O_(4) follows an adsorbate evolution mechanism pathway,where the energy barrier of rate-determining step for OER on(FeCoNiCrMo)_(3)O_(4) is substantially lowered.Also,methanol molecular probe experiment suggests that a weakened ^(*)OH bonding on the(FeCoNiCrMo)_(3)O_(4) surface and a rapid deprotonation of ^(*)OH,further enhancing its OER performance.This work provides a feasible solution for designing efficient high entropy oxides electrocatalysts for OER,accelerating the practical process of water electrolysis for H2 production.展开更多
Room-temperature phosphorescence(RTP)materials exhibiting long emission lifetimes have gained increasing attention owing to their potential applications in encryption,anti-counterfeiting,and sensing.However,most polym...Room-temperature phosphorescence(RTP)materials exhibiting long emission lifetimes have gained increasing attention owing to their potential applications in encryption,anti-counterfeiting,and sensing.However,most polymers exhibit a short RTP lifetime(<1 s)because of their unstable triplet excitons.Herein,a new strategy of polymer chain stabilized phosphorescence(PCSP),which yields a new kind of RTP polymers with an ultralong lifetime and a sensitive oxygen response,has been reported.The rigid polymer chains of poly(methyl mathacrylate)(PMMA)immobilize the emitter molecules through multiple interactions between them,giving rise to efficient RTP.Meanwhile,the loosely-packed amorphous polymer chains allow oxygen to diffuse inside,endowing the doped polymers with oxygen sensitivity.Flexible and transparent polymer films exhibited an impressive ultralong RTP lifetime of 2.57 s at room temperature in vacuum,which was among the best performance of PMMA.Intriguingly,their RTP was rapidly quenched in the presence of oxygen.Furthermore,RTP microparticles with a diameter of 1.63μm were synthesized using in situ dispersion polymerization technique.Finally,oxygen sensors for quick,visual,and quantitative oxygen detection were developed based on the RTP microparticles through phosphorescence lifetime and image analysis.With distinctive advantages such as an ultralong lifetime,oxygen sensitivity,ease of fabrication,and cost-effectiveness,PCSP opens a new avenue to sensitive materials for oxygen detection.展开更多
A series of“half-sandwich”bis(imino)pyridyl iron complexes with a substituted 8-(p-Xphenyl)naphthylamine(X=OMe,Me,CF3)was designed and synthesized by combining weakπ-πinteraction with steric and electronic tunings...A series of“half-sandwich”bis(imino)pyridyl iron complexes with a substituted 8-(p-Xphenyl)naphthylamine(X=OMe,Me,CF3)was designed and synthesized by combining weakπ-πinteraction with steric and electronic tunings.The weak noncovalentπ-πinteraction as well as the steric and electronic effects of bis(imino)pyridyl iron complexes were identified by experimental analyses and calculations.The roles of weakπ-πinteraction,steric bulk,and electronic tuning on the ethylene polymerization performance of bis(imino)pyridyl iron catalysts were studied in detail.The combination ofπ-πinteraction with steric and electronic tunings can access to thermally stable bis(imino)pyridyl iron at 130°C.展开更多
Metal hydrides serve as crucial intermediates in many chemical processes,facilitating the utilization of hydrogen resources.Traditionally,three-centre metal hydrides have been viewed as less reactive due to their mult...Metal hydrides serve as crucial intermediates in many chemical processes,facilitating the utilization of hydrogen resources.Traditionally,three-centre metal hydrides have been viewed as less reactive due to their multi-stabilization effects.However,recent discoveries show the"three-centre four-electron"(3c-4e)bridging hydride bond exhibits significant activity in boryl transition metal systems.This research employs computational techniques to explore the factors that influence the formation of the 3c-4e bridging hydride,focusing on boryl 3d non-noble transition metals ranging from chromium(Cr)to nickel(Ni).By analyzing bond distances and bond orders,the study sheds light on the electronic and structural characteristics of the B-H-M bridging hydride.It reveals a clear link between the metal centre’s redox properties and the emergence of bridging hydrides.Specifically,metal centres like Cr and Co,which have lower oxidation states and electronegativity,are more inclined to form active 3c-4e bridging hydrides.These insights,derived from computational analyses,offer valuable guidelines for the development of active 3c-4e bridging metal hydrides,thereby contributing to the advancement of new hydrogen transformation catalysts.展开更多
Designing efficient and durable hydrogen evolution reaction(HER)catalysts for seawater electrolysis is crucial for large-scale hydrogen production.Here,we introduce a theory-driven design of metal/WN electrocatalysts,...Designing efficient and durable hydrogen evolution reaction(HER)catalysts for seawater electrolysis is crucial for large-scale hydrogen production.Here,we introduce a theory-driven design of metal/WN electrocatalysts,with metal strongly coupled to lattice-matched WN.Theoretical calculations for Pt/WN reveal that W sites enhance H_(2)O adsorption/dissociation,optimizing Pt's H binding.The prepared Pt/WN@CP nanorods can catalyze HER with low overpotentials of 107 and 113 mV at 500 mA cm^(-2)in alkaline water/seawater,respectively,surpassing Pt/C.Extended calculations and experiments show that the optimized Ni/WN@CP-90 achieves an optimal ΔG_(H*)and overpotential of 219 mV at 500 mA cm^(-2)in alkaline seawater,demonstrating the versatility of the WN support to promote HER activity.Notably,the anion exchange membrane water electrolyzer(AEMWE)constructed by Pt/WN@CP or Ni/WN@CP-90 with NiFe-LDH@NF demonstrates outstanding hydrogen production activity with excellent Faraday efficiency(~100%)and durability(120 h),indicating the potential application of WN-supported catalysts for efficient and stable seawater electrolysis.展开更多
Polymerizations of linear α-olefins(CnH2n, CH2=CH―R, R = Cn-2) catalyzed by early transition metals typically afford amorphous polymers with alkyl chains(Cn-2), while chain-straightening polymerizations of α-olefin...Polymerizations of linear α-olefins(CnH2n, CH2=CH―R, R = Cn-2) catalyzed by early transition metals typically afford amorphous polymers with alkyl chains(Cn-2), while chain-straightening polymerizations of α-olefins with nickel-based catalysts produce semicrystalline polyolefins. Polymerizations of various α-olefins were carried out using an α-diamine nickel catalyst with a significantly distorted chelating ring. The influences of temperature, monomer concentration, and chain length of α-olefins on polyolefin microstructure were examined in detail. The α-diamine nickel catalyst realized highly regioselective 2,1-insertion of α-olefins regardless of reaction temperature and monomer concentration. Increased chain length of α-olefins led to the formation of more linear polyolefin.Semicrystalline polyolefins with high melting temperatures(Tm) were made from α-olefins through highly regioselective 2,1-insertion and precise chain-straightening.展开更多
A series of unsymmetrical a-diimine nickel complexes with various backbones and substituted aniline moieties were synthesized and characterized. The crystallographic analysis of the nickel complexes confirmed the exis...A series of unsymmetrical a-diimine nickel complexes with various backbones and substituted aniline moieties were synthesized and characterized. The crystallographic analysis of the nickel complexes confirmed the existence of meso-and rac-configuration in solid structure. Nickel complexes after activation by MAO were screened for ethylene polymerization to evaluate backbone substituent effect on synthesis of bimodal PE. Acenaphthyl nickel complex with planar backbone afforded a bimodal PE with a broad polydispersity, whereas camphyl nickel complex with rigid and bulky backbone afforded a monomodal PE with a narrow polydispersity. Steric effect of aniline moiety for acenaphthyl nickel complex was also examined, and bimodal PE with dominant high-molecular-weight fraction was obtained by modifying substituents on aniline moiety.展开更多
A diamine(WuFDA) containing vertical rigid non-planar conjugated fluorene moiety and low polarizability group(C―F)was designed and synthesized through three steps of reactions(halogenated reaction, Suzuki coupling re...A diamine(WuFDA) containing vertical rigid non-planar conjugated fluorene moiety and low polarizability group(C―F)was designed and synthesized through three steps of reactions(halogenated reaction, Suzuki coupling reaction, and reduction reaction).Four kinds of high performance functional polyimides(WuFPI-6 F, WuFPI-BP, WuFPI-BT, and WuFPI-PM) were thus prepared by the condensation polymerization of WuFDA with four commercial dianhydride 6 FDA, BPDA, BTDA, and PMDA, respectively. The polyimides exhibited low dielectric constant, excellent thermal stability, outstanding solubility, good film-forming property, and mechanical properties. The dielectric constants of the polyimides were in the range of 2.28-2.88(f = 10~4 Hz). The 5% weight-loss temperatures(Td 5%)in nitrogen were in the range of 555-584 °C, and the glass transition temperatures(T_g) were in the range of 408-448 °C. The weight loss of WuFPI-BP maintaining at 450 and 500 °C for half an hour was only 0.33% and 1.26%, respectively. All the WuFPIs could be dissolved in almost all organic solvents, even chloroform. The tensile strength and tensile modulus of these films were in the ranges of 78.6-85.7 MPa and 3.1-3.2 GPa, respectively. In addition, the polyimides displayed light color with special fluorescent and resistive switching(ON-OFF) characteristics; the maximum fluorescence emission was observed at 422-424 nm in NMP solution and at 470-548 nm in film state. The memory devices with the configuration of indium tin oxide/WuFPIs/aluminum(ITO/WuFPIs/Al) exhibited distinct volatile memory characteristics of static random access memory(SRAM), with an ON/OFF current ratio of 10~5-10~6. These functional polyimides showed attractive potential applications in the field of high performance flexible polymer photoelectronic devices or polymer memory devices.展开更多
High-performance low-k and low-loss circuit materials are urgently needed in the field of microelectronics due to the upcoming FifthGeneration Mobile Communications Technology(5 G Technology).Herein,a facile design st...High-performance low-k and low-loss circuit materials are urgently needed in the field of microelectronics due to the upcoming FifthGeneration Mobile Communications Technology(5 G Technology).Herein,a facile design strategy for non-fluorinated intrinsic low-k and low-loss polyimides is reported by fully considering the secondary relaxation behaviors of the polymer chains.A new amorphous non-fluorinated polymer(TmBPPA)with a k value of 2.23 and a loss tangent lower than 3.94×10^-3 at 104 Hz has been designed and synthesized,which to the best of our knowledge is the lowest value amongst the non-fluorinated and non-porous polymers reported in literature.Meanwhile,TmBPPA exhibits excellent overall properties,such as excellent thermostability,good mechanical properties,low moisture absorption,and high bonding strength.As high-performance flexible circuit materials,all these characteristics are highly expected to meet the present and future demands for high density,high speed,and high frequency electronic circuit used in 5 G wireless networks.展开更多
Drug-resistance and drastic side effects are two major issues of traditional chemotherapy which may result in trail failure even death.Nanoparticle-mediated multidrug combination treatment has been proven to be a feas...Drug-resistance and drastic side effects are two major issues of traditional chemotherapy which may result in trail failure even death.Nanoparticle-mediated multidrug combination treatment has been proven to be a feasible strategy to overcome these challenges.In the present study,amphipathic block polymer of methoxyl poly(ethylene glycol)-poly(aspartyl(dibutylethylenediamine)-co-phenylalanine)(m PEG-P(Asp(DBA)-co-Phe))was synthesized and self-assembled into p H-responsive polymeric vesicle.The vesicle was utilized to co-deliver cancer-associated epidermal growth factor(EGFR)inhibitor of afatinib and DNA-damaging chemotherapeutic doxorubicin hydrochloride(DOX)for enhanced non-small-cell lung cancer(NSCLC)therapy.As evaluated in vitro,the p H-responsive design of nanovesicle resulted in a rapid release of encapsulated drugs into tumor cells and caused enhanced cell apoptosis.In addition,in vivo therapeutic studies were conducted and the results evidenced that the co-delevery of DOX and afatinib using p H-sensitive nanovector was a promising strategy for NSCLC treatment.展开更多
Thermoresponsive fluorescent polymers(TFPs) with unique temperature-dependent luminescent properties are of great importance for the development of new functional devices in recent years. Herein, we facilely synthesiz...Thermoresponsive fluorescent polymers(TFPs) with unique temperature-dependent luminescent properties are of great importance for the development of new functional devices in recent years. Herein, we facilely synthesized an efficient blue-emissive polymer, abbreviated as PCB-TPE, using tetraphenylethene(TPE) as the main building block. PCB-TPE is thermally stable with a novel property of aggregation induced emission(AIE). The thermoresponsive property and mechanism of PCB-TPE were investigated. Its emission shows temperature-dependent features and reveals fine details in the thermal transitions from-10 °C to 60 °C. The polymer offers a platform for the development of efficient luminescent materials for further biological and optoelectronic applications.展开更多
Antibody targeted delivery is an effective strategy to improve the diagnostic imaging outcome of nanoscale imaging agents in the focal areas. Dual targeting micelles encapsulating superparamagnetic iron oxide were pre...Antibody targeted delivery is an effective strategy to improve the diagnostic imaging outcome of nanoscale imaging agents in the focal areas. Dual targeting micelles encapsulating superparamagnetic iron oxide were prepared from the amphiphilic block copolymer poly（ethylene glycol）-poly（e-caprolactone） （PEG-b-PCL） with different targeting ligands cRGD and scFv-ErbB single chain antibody conjugated to the distal ends of PEG block. The breast cancer animal model was established by subcutaneous injecting the BT474 cells into the BALB/c-nu female nude mice and then employed to assess the potential of the dual ligand targeted magnetic micelles as a novel MRI contrast agent on a 1.5 T clinical MR/scanner. The T2 signal intensity of the tumor in animals receiving the dual ligand targeted magnetic micelles via tail vein decreased more significantly than the single ligand targeted and nontargeted magnetic micelles. These results indicate that the dual ligand targeted magnetic micelles, cRGD/scFv-ErbB-PEG-PCL-SPION, have great potential to act as a new type of effective nanoscale MRI contrast agent for early diagnosis of breast cancer.展开更多
Colloidal synthesis of metal nanoclusters will inevitably lead to the blockage of catalytically active sites by organic ligands.Here,taking[Au_(25)(PET)_(18)]-(PET=2-phenylethanethiol)nanocluster as a model catalyst,t...Colloidal synthesis of metal nanoclusters will inevitably lead to the blockage of catalytically active sites by organic ligands.Here,taking[Au_(25)(PET)_(18)]-(PET=2-phenylethanethiol)nanocluster as a model catalyst,this work reports a feasible procedure to achieve the controllably partial removal of thiolate ligands from unsupported[Au_(25)(PET)_(18)]-nanoclusters with the preservation of the core structure.This procedure shortens the processing duration by rapid heating and cooling on the basis of traditional annealing treatment,avoiding the reconfiguration or agglomeration of Au_(25)nanoclusters,where the degree of dethiolation can be regulated by the control of duration.This work finds that a moderate degree of dethiolation can expose the Au active sites while maintaining the suppression of the competing hydrogen evolution reaction.Consequently,the activity and selectivity towards CO formation in electrochemical CO_(2)reduction reaction of Au_(25)nanoclusters can be promoted.This work provides a new approach for the removal of thiolate ligands from atomically precise gold nanoclusters.展开更多
Deciphering the atomic‐level properties and mechanism of electrocatalysts for water splitting is vital for the development of highly active non‐noble‐metal catalysts.Herein,we conduct a detailed study of layered cr...Deciphering the atomic‐level properties and mechanism of electrocatalysts for water splitting is vital for the development of highly active non‐noble‐metal catalysts.Herein,we conduct a detailed study of layered crystalline CoMoO_(4)using density functional theory(DFT)calculations.The layered arrangement of CoMoO_(4)along the[110]lattice direction is observed,and the two thermodynamically stable and most exposed(110)A and(001)A crystal facets are selected among all low‐index facets by surface energy calculations and Wulff construction to study the electrocatalytic activity for alkaline water splitting and corresponding mechanism.CoMoO_(4)with an exposed(110)A facet(i.e.,CMO(110)A)exhibited a high hydrogen evolution reaction(HER)activity,with aΔGH*of 0.22 eV,which is similar to that of Pt because the adsorbed H is allowed to interact with two oxygen atoms(O_(3)and Oadj).The(110)A facet also possesses better H_(2)O adsorption and dissociation abilities than the(001)A facet,benefiting the HER performance in alkaline solutions.Moreover,the overpotential of the(110)A facet for the electrocatalytic oxygen evolution reaction(OER)is only 0.74 V according to the Gibbs free‐energy calculation,this overpotential is lower than that of the(001)A facet(0.84 V)owing to the stronger binding and more stable adsorption states between Co and O for the intermediate*O.By allowing us to identify highly active facets and sites,this approach guided the selective synthesis of CoMoO_(4)and its isostructural substances,such as Mn(Ni,Fe)MoO4 nanocatalysts,for alkaline water splitting.展开更多
文摘Ensuring high electrocatalytic performance simultaneously with low or even no precious-metal usage is still a big challenge for the development of electrocatalysts toward oxygen evolution reaction(OER)in anion exchange membrane water electrolysis.Here,homogeneous high entropy oxide(HEO)film is in-situ fabricated on nickel foam(NF)substrate via magnetron sputtering technology without annealing process in air,which is composed of many spinel-structured(FeCoNiCrMo)_(3)O_(4) grains with an average particle size of 2.5 nm.The resulting HEO film(abbreviated as(FeCoNiCr-Mo)_(3)O_(4))exhibits a superior OER performance with a low OER overpotential of 216 mV at 10 mA cm^(–2) and steadily operates at 100 mA cm^(–2) for 200 h with a decay of only 272μV h^(–1),which is far better than that of commercial IrO_(2) catalyst(290 mV,1090μV h^(–1)).Tetramethylammonium cation(TMA^(+))probe experiment,activation energy analysis and theoretical calculations unveil that the OER on(FeCoNiCrMo)_(3)O_(4) follows an adsorbate evolution mechanism pathway,where the energy barrier of rate-determining step for OER on(FeCoNiCrMo)_(3)O_(4) is substantially lowered.Also,methanol molecular probe experiment suggests that a weakened ^(*)OH bonding on the(FeCoNiCrMo)_(3)O_(4) surface and a rapid deprotonation of ^(*)OH,further enhancing its OER performance.This work provides a feasible solution for designing efficient high entropy oxides electrocatalysts for OER,accelerating the practical process of water electrolysis for H2 production.
基金National Natural Science Foundation of China(No.22475241)Guangdong Basic and Applied Basic Research Foundation(Nos.2022A1515010826 and 2023A1515012696)the Fundamental Research Funds for the Central Universities(Nos.17lgjc03 and 18lgpy04).
文摘Room-temperature phosphorescence(RTP)materials exhibiting long emission lifetimes have gained increasing attention owing to their potential applications in encryption,anti-counterfeiting,and sensing.However,most polymers exhibit a short RTP lifetime(<1 s)because of their unstable triplet excitons.Herein,a new strategy of polymer chain stabilized phosphorescence(PCSP),which yields a new kind of RTP polymers with an ultralong lifetime and a sensitive oxygen response,has been reported.The rigid polymer chains of poly(methyl mathacrylate)(PMMA)immobilize the emitter molecules through multiple interactions between them,giving rise to efficient RTP.Meanwhile,the loosely-packed amorphous polymer chains allow oxygen to diffuse inside,endowing the doped polymers with oxygen sensitivity.Flexible and transparent polymer films exhibited an impressive ultralong RTP lifetime of 2.57 s at room temperature in vacuum,which was among the best performance of PMMA.Intriguingly,their RTP was rapidly quenched in the presence of oxygen.Furthermore,RTP microparticles with a diameter of 1.63μm were synthesized using in situ dispersion polymerization technique.Finally,oxygen sensors for quick,visual,and quantitative oxygen detection were developed based on the RTP microparticles through phosphorescence lifetime and image analysis.With distinctive advantages such as an ultralong lifetime,oxygen sensitivity,ease of fabrication,and cost-effectiveness,PCSP opens a new avenue to sensitive materials for oxygen detection.
基金supported by the State Key Research Development Program of China(No.2021YFB3800701)National Natural Science Foundation of China(NSFC,No.52173016)+2 种基金Guangdong Basic and Applied Basic Research Foundation(Nos.2024A1515012784,2024A1515011102,and 2023A1515110549)Fundamental Research Funds for the Central Universities,Sun Yat-sen University(No.24qnpy047)PetroChina Scientific and Technological Projects(No.2022DJ6308).
文摘A series of“half-sandwich”bis(imino)pyridyl iron complexes with a substituted 8-(p-Xphenyl)naphthylamine(X=OMe,Me,CF3)was designed and synthesized by combining weakπ-πinteraction with steric and electronic tunings.The weak noncovalentπ-πinteraction as well as the steric and electronic effects of bis(imino)pyridyl iron complexes were identified by experimental analyses and calculations.The roles of weakπ-πinteraction,steric bulk,and electronic tuning on the ethylene polymerization performance of bis(imino)pyridyl iron catalysts were studied in detail.The combination ofπ-πinteraction with steric and electronic tunings can access to thermally stable bis(imino)pyridyl iron at 130°C.
基金supported by the National Natural Science Foundation of Chian(NSFC,Nos.22373118 and 22231002)the Guangdong Basic and Applied Basic Research Foundation(No.2024B1515040025)the Fundamental Research Funds for the Central Universities.
文摘Metal hydrides serve as crucial intermediates in many chemical processes,facilitating the utilization of hydrogen resources.Traditionally,three-centre metal hydrides have been viewed as less reactive due to their multi-stabilization effects.However,recent discoveries show the"three-centre four-electron"(3c-4e)bridging hydride bond exhibits significant activity in boryl transition metal systems.This research employs computational techniques to explore the factors that influence the formation of the 3c-4e bridging hydride,focusing on boryl 3d non-noble transition metals ranging from chromium(Cr)to nickel(Ni).By analyzing bond distances and bond orders,the study sheds light on the electronic and structural characteristics of the B-H-M bridging hydride.It reveals a clear link between the metal centre’s redox properties and the emergence of bridging hydrides.Specifically,metal centres like Cr and Co,which have lower oxidation states and electronegativity,are more inclined to form active 3c-4e bridging hydrides.These insights,derived from computational analyses,offer valuable guidelines for the development of active 3c-4e bridging metal hydrides,thereby contributing to the advancement of new hydrogen transformation catalysts.
基金financial support of the National Natural Science Foundation of China(22478450,22478451,22408408)Guangdong Basic and Applied Basic Research Foundation(2024A1515012565,2021A1515010167,2022A1515011196)+3 种基金Guangzhou Key R&D Program/Plan Unveiled Flagship Project(20220602JBGS02)Guangzhou Basic and Applied Basic Research Project(202201011449)Research Fund Program of Guangdong Provincial Key Laboratory of Fuel Cell Technology(FC202220,FC202216)100 Talent Research Foundation of Sun Yat-sen University(76110-12230029)。
文摘Designing efficient and durable hydrogen evolution reaction(HER)catalysts for seawater electrolysis is crucial for large-scale hydrogen production.Here,we introduce a theory-driven design of metal/WN electrocatalysts,with metal strongly coupled to lattice-matched WN.Theoretical calculations for Pt/WN reveal that W sites enhance H_(2)O adsorption/dissociation,optimizing Pt's H binding.The prepared Pt/WN@CP nanorods can catalyze HER with low overpotentials of 107 and 113 mV at 500 mA cm^(-2)in alkaline water/seawater,respectively,surpassing Pt/C.Extended calculations and experiments show that the optimized Ni/WN@CP-90 achieves an optimal ΔG_(H*)and overpotential of 219 mV at 500 mA cm^(-2)in alkaline seawater,demonstrating the versatility of the WN support to promote HER activity.Notably,the anion exchange membrane water electrolyzer(AEMWE)constructed by Pt/WN@CP or Ni/WN@CP-90 with NiFe-LDH@NF demonstrates outstanding hydrogen production activity with excellent Faraday efficiency(~100%)and durability(120 h),indicating the potential application of WN-supported catalysts for efficient and stable seawater electrolysis.
基金National Natural Science Foundation of China(U1601206,51872336,51422307,51602107,51702262)National Social Science Foundation of China(17BXW104)+3 种基金National Program for Support of Top-notch Young ProfessionalsScience Foundation of Ministry of Education of China(15YJC630141)Tip-top Scientific and Technical Innovative Youth Talents of Guangdong Special Support Program(2014TQ01C337)Fundamental Research Funds for the Central Universities(18lgzd10)~~
基金financially supported by the National Natural Science Foundation of China (Nos. 21674130, 51873234)Natural Science Foundation of Guangdong Province (No. 2017A030310 349)+1 种基金Fundamental Research Funds for the Central Universities (No. 17lgjc02)PetroChina Innovation Foundation (No. 2017D-5007-0505)
文摘Polymerizations of linear α-olefins(CnH2n, CH2=CH―R, R = Cn-2) catalyzed by early transition metals typically afford amorphous polymers with alkyl chains(Cn-2), while chain-straightening polymerizations of α-olefins with nickel-based catalysts produce semicrystalline polyolefins. Polymerizations of various α-olefins were carried out using an α-diamine nickel catalyst with a significantly distorted chelating ring. The influences of temperature, monomer concentration, and chain length of α-olefins on polyolefin microstructure were examined in detail. The α-diamine nickel catalyst realized highly regioselective 2,1-insertion of α-olefins regardless of reaction temperature and monomer concentration. Increased chain length of α-olefins led to the formation of more linear polyolefin.Semicrystalline polyolefins with high melting temperatures(Tm) were made from α-olefins through highly regioselective 2,1-insertion and precise chain-straightening.
基金supported by NSFC (Nos. 21274167, 51173209 and 21174164)CNPC Innovation Foundationthe Fundamental Research Funds for the Central Universities (Project 10lgpy10)
文摘A series of unsymmetrical a-diimine nickel complexes with various backbones and substituted aniline moieties were synthesized and characterized. The crystallographic analysis of the nickel complexes confirmed the existence of meso-and rac-configuration in solid structure. Nickel complexes after activation by MAO were screened for ethylene polymerization to evaluate backbone substituent effect on synthesis of bimodal PE. Acenaphthyl nickel complex with planar backbone afforded a bimodal PE with a broad polydispersity, whereas camphyl nickel complex with rigid and bulky backbone afforded a monomodal PE with a narrow polydispersity. Steric effect of aniline moiety for acenaphthyl nickel complex was also examined, and bimodal PE with dominant high-molecular-weight fraction was obtained by modifying substituents on aniline moiety.
基金financial support by the National 973 Program of China (No. 2014CB643605)the National Natural Science Foundation of China (Nos. 51373204 and 51873239)+3 种基金the Science and Technology Project of Guangdong Province (Nos. 2015B090915003 and 2015B090913003)the China Postdoctoral Science Foundation (No. 2017M612801)the Leading Scientific, Technical and Innovation Talents of Guangdong Special Support Program (No. 2016TX03C295)the Fundamental Research Funds for the Central Universities (No. 161gzd08)
文摘A diamine(WuFDA) containing vertical rigid non-planar conjugated fluorene moiety and low polarizability group(C―F)was designed and synthesized through three steps of reactions(halogenated reaction, Suzuki coupling reaction, and reduction reaction).Four kinds of high performance functional polyimides(WuFPI-6 F, WuFPI-BP, WuFPI-BT, and WuFPI-PM) were thus prepared by the condensation polymerization of WuFDA with four commercial dianhydride 6 FDA, BPDA, BTDA, and PMDA, respectively. The polyimides exhibited low dielectric constant, excellent thermal stability, outstanding solubility, good film-forming property, and mechanical properties. The dielectric constants of the polyimides were in the range of 2.28-2.88(f = 10~4 Hz). The 5% weight-loss temperatures(Td 5%)in nitrogen were in the range of 555-584 °C, and the glass transition temperatures(T_g) were in the range of 408-448 °C. The weight loss of WuFPI-BP maintaining at 450 and 500 °C for half an hour was only 0.33% and 1.26%, respectively. All the WuFPIs could be dissolved in almost all organic solvents, even chloroform. The tensile strength and tensile modulus of these films were in the ranges of 78.6-85.7 MPa and 3.1-3.2 GPa, respectively. In addition, the polyimides displayed light color with special fluorescent and resistive switching(ON-OFF) characteristics; the maximum fluorescence emission was observed at 422-424 nm in NMP solution and at 470-548 nm in film state. The memory devices with the configuration of indium tin oxide/WuFPIs/aluminum(ITO/WuFPIs/Al) exhibited distinct volatile memory characteristics of static random access memory(SRAM), with an ON/OFF current ratio of 10~5-10~6. These functional polyimides showed attractive potential applications in the field of high performance flexible polymer photoelectronic devices or polymer memory devices.
基金finincially supported by the National Natural Science Foundation of China (Nos. 51373204 and 51873239)the National 973 Program of China (No. 2014CB643605)+3 种基金the Science and Technology Project of Guangdong Province (Nos. 2015B090915003 and 2015B090913003)the Leading Scientific, Technical and Innovation Talents of Guangdong Special Support Program (No. 2016TX03C295)the China Postdoctoral Science Foundation (No. 2017M612801)the Fundamental Research Funds of Sun Yat-sen University
文摘High-performance low-k and low-loss circuit materials are urgently needed in the field of microelectronics due to the upcoming FifthGeneration Mobile Communications Technology(5 G Technology).Herein,a facile design strategy for non-fluorinated intrinsic low-k and low-loss polyimides is reported by fully considering the secondary relaxation behaviors of the polymer chains.A new amorphous non-fluorinated polymer(TmBPPA)with a k value of 2.23 and a loss tangent lower than 3.94×10^-3 at 104 Hz has been designed and synthesized,which to the best of our knowledge is the lowest value amongst the non-fluorinated and non-porous polymers reported in literature.Meanwhile,TmBPPA exhibits excellent overall properties,such as excellent thermostability,good mechanical properties,low moisture absorption,and high bonding strength.As high-performance flexible circuit materials,all these characteristics are highly expected to meet the present and future demands for high density,high speed,and high frequency electronic circuit used in 5 G wireless networks.
基金financially supported by the National Basic Research Program of China (No. 2015CB755500)the Natural Science Foundation of Guangdong Province (No. 2014A030312018)Science and Technology Planning Project of Guangdong Province (No. 2016A020215088)
文摘Drug-resistance and drastic side effects are two major issues of traditional chemotherapy which may result in trail failure even death.Nanoparticle-mediated multidrug combination treatment has been proven to be a feasible strategy to overcome these challenges.In the present study,amphipathic block polymer of methoxyl poly(ethylene glycol)-poly(aspartyl(dibutylethylenediamine)-co-phenylalanine)(m PEG-P(Asp(DBA)-co-Phe))was synthesized and self-assembled into p H-responsive polymeric vesicle.The vesicle was utilized to co-deliver cancer-associated epidermal growth factor(EGFR)inhibitor of afatinib and DNA-damaging chemotherapeutic doxorubicin hydrochloride(DOX)for enhanced non-small-cell lung cancer(NSCLC)therapy.As evaluated in vitro,the p H-responsive design of nanovesicle resulted in a rapid release of encapsulated drugs into tumor cells and caused enhanced cell apoptosis.In addition,in vivo therapeutic studies were conducted and the results evidenced that the co-delevery of DOX and afatinib using p H-sensitive nanovector was a promising strategy for NSCLC treatment.
基金financially supported by the National Natural Science Foundation of China (No. 21374136)the Fundamental Research Funds for the Central Universities (Nos. 17lgjc03 and 18lgpy04)the Opening Project of the Key Laboratory of Polymer Processing Engineering (South China University of Technology, Ministry of Education, No. KFKT1703)
文摘Thermoresponsive fluorescent polymers(TFPs) with unique temperature-dependent luminescent properties are of great importance for the development of new functional devices in recent years. Herein, we facilely synthesized an efficient blue-emissive polymer, abbreviated as PCB-TPE, using tetraphenylethene(TPE) as the main building block. PCB-TPE is thermally stable with a novel property of aggregation induced emission(AIE). The thermoresponsive property and mechanism of PCB-TPE were investigated. Its emission shows temperature-dependent features and reveals fine details in the thermal transitions from-10 °C to 60 °C. The polymer offers a platform for the development of efficient luminescent materials for further biological and optoelectronic applications.
基金supported by the 863 Programs of China(No.2009AA03Z310)National Natural Science Foundation of China(Nos.21174166,30973419)+5 种基金the Ph.D.Programs Foundation of Ministry of Education of China(No.20100171110011)the Postdoctoral Foundation(No.201003370)Natural Science Foundation(Nos.9351027501000003,S2011020003140)S&T Programs of Guangdong Province(Nos.2010B031500011,2009B030803003,2009B030801107,2012B031800135)SYSU Projects for Promotion of Key and Emerging Interdisciplinary Researches(10ykjc18)Young Teachers(11lgpy44)
文摘Antibody targeted delivery is an effective strategy to improve the diagnostic imaging outcome of nanoscale imaging agents in the focal areas. Dual targeting micelles encapsulating superparamagnetic iron oxide were prepared from the amphiphilic block copolymer poly（ethylene glycol）-poly（e-caprolactone） （PEG-b-PCL） with different targeting ligands cRGD and scFv-ErbB single chain antibody conjugated to the distal ends of PEG block. The breast cancer animal model was established by subcutaneous injecting the BT474 cells into the BALB/c-nu female nude mice and then employed to assess the potential of the dual ligand targeted magnetic micelles as a novel MRI contrast agent on a 1.5 T clinical MR/scanner. The T2 signal intensity of the tumor in animals receiving the dual ligand targeted magnetic micelles via tail vein decreased more significantly than the single ligand targeted and nontargeted magnetic micelles. These results indicate that the dual ligand targeted magnetic micelles, cRGD/scFv-ErbB-PEG-PCL-SPION, have great potential to act as a new type of effective nanoscale MRI contrast agent for early diagnosis of breast cancer.
基金the financial support of the Training Program of the Major Research Plan of the National Natural Science Foundation of China(92061124)the National Natural Science Foundation of China(21975292,21978331,22068008,and 52101186)+3 种基金the Guangdong Basic and Applied Basic Research Foundation(2021A1515010167 and 2022A1515011196)the Guangzhou Key R&D Program/Plan Unveiled Flagship Project(20220602JBGS02)the Guangzhou Basic and Applied Basic Research Project(202201011449)the Research Fund Program of Guangdong Provincial Key Laboratory of Fuel Cell Technology(FC202220 and FC202216)。
文摘Colloidal synthesis of metal nanoclusters will inevitably lead to the blockage of catalytically active sites by organic ligands.Here,taking[Au_(25)(PET)_(18)]-(PET=2-phenylethanethiol)nanocluster as a model catalyst,this work reports a feasible procedure to achieve the controllably partial removal of thiolate ligands from unsupported[Au_(25)(PET)_(18)]-nanoclusters with the preservation of the core structure.This procedure shortens the processing duration by rapid heating and cooling on the basis of traditional annealing treatment,avoiding the reconfiguration or agglomeration of Au_(25)nanoclusters,where the degree of dethiolation can be regulated by the control of duration.This work finds that a moderate degree of dethiolation can expose the Au active sites while maintaining the suppression of the competing hydrogen evolution reaction.Consequently,the activity and selectivity towards CO formation in electrochemical CO_(2)reduction reaction of Au_(25)nanoclusters can be promoted.This work provides a new approach for the removal of thiolate ligands from atomically precise gold nanoclusters.
文摘Deciphering the atomic‐level properties and mechanism of electrocatalysts for water splitting is vital for the development of highly active non‐noble‐metal catalysts.Herein,we conduct a detailed study of layered crystalline CoMoO_(4)using density functional theory(DFT)calculations.The layered arrangement of CoMoO_(4)along the[110]lattice direction is observed,and the two thermodynamically stable and most exposed(110)A and(001)A crystal facets are selected among all low‐index facets by surface energy calculations and Wulff construction to study the electrocatalytic activity for alkaline water splitting and corresponding mechanism.CoMoO_(4)with an exposed(110)A facet(i.e.,CMO(110)A)exhibited a high hydrogen evolution reaction(HER)activity,with aΔGH*of 0.22 eV,which is similar to that of Pt because the adsorbed H is allowed to interact with two oxygen atoms(O_(3)and Oadj).The(110)A facet also possesses better H_(2)O adsorption and dissociation abilities than the(001)A facet,benefiting the HER performance in alkaline solutions.Moreover,the overpotential of the(110)A facet for the electrocatalytic oxygen evolution reaction(OER)is only 0.74 V according to the Gibbs free‐energy calculation,this overpotential is lower than that of the(001)A facet(0.84 V)owing to the stronger binding and more stable adsorption states between Co and O for the intermediate*O.By allowing us to identify highly active facets and sites,this approach guided the selective synthesis of CoMoO_(4)and its isostructural substances,such as Mn(Ni,Fe)MoO4 nanocatalysts,for alkaline water splitting.
