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
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
Osteosarcoma is a malignant tumor originating from bone tissue that progresses rapidly and has a poor patient prognosis.Immunotherapy has shown great potential in the treatment of osteosarcoma.However,the immunosuppre...Osteosarcoma is a malignant tumor originating from bone tissue that progresses rapidly and has a poor patient prognosis.Immunotherapy has shown great potential in the treatment of osteosarcoma.However,the immunosuppressive microenvironment severely limits the efficacy of osteosarcoma treatment.The dual pH-sensitive nanocarrier has emerged as an effective antitumor drug delivery system that can selectively release drugs into the acidic tumor microenvironment.Here,we prepared a dual pH-sensitive nanocarrier,loaded with the photosensitizer Chlorin e6(Ce6)and CD47 monoclonal antibodies(aCD47),to deliver synergistic photodynamic and immunotherapy of osteosarcoma.On laser irradiation,Ce6 can generate reactive oxygen species(ROS)to kill cancer cells directly and induces immunogenic tumor cell death(ICD),which further facilitates the dendritic cell maturation induced by blockade of CD47 by aCD47.Moreover,both calreticulin released during ICD and CD47 blockade can accelerate phagocytosis of tumor cells by macrophages,promote antigen presentation,and eventually induce T lymphocyte-mediated antitumor immunity.Overall,the dual pH-sensitive nanodrug loaded with Ce6 and aCD47 showed excellent immune-activating and anti-tumor effects in osteosarcoma,which may lay the theoretical foundation for a novel combination model of osteosarcoma treatment.展开更多
Remarkable progress has characterized the field of electrocatalysis in recent decades,driven in part by an enhanced comprehension of catalyst structures and mechanisms at the nanoscale.Atomically precise metal nanoclu...Remarkable progress has characterized the field of electrocatalysis in recent decades,driven in part by an enhanced comprehension of catalyst structures and mechanisms at the nanoscale.Atomically precise metal nanoclusters,serving as exemplary models,significantly expand the range of accessible structures through diverse cores and ligands,creating an exceptional platform for the investigation of catalytic reactions.Notably,ligand‐protected Au nanoclusters(NCs)with precisely defined core numbers offer a distinct advantage in elucidating the correlation between their specific structures and the reaction mechanisms in electrocatalysis.The strategic modulation of the fine microstructures of Au NCs presents crucial opportunities for tailoring their electrocatalytic performance across various reactions.This review delves into the profound structural effects of Au NC cores and ligands in electrocatalysis,elucidating their underlying mechanisms.A detailed exploration of the fundamentals of Au NCs,considering core and ligand structures,follows.Subsequently,the interaction between the core and ligand structures of Au NCs and their impact on electrocatalytic performance in diverse reactions are examined.Concluding the discourse,challenges and personal prospects are presented to guide the rational design of efficient electrocatalysts and advance electrocatalytic reactions.展开更多
Herein,we report the NHC-Ru catalyst system that realizes the chemo-selective transformation of ketones with methanol.By simply changing the base,a broad range of structurally diverse ketones,could be selectively and ...Herein,we report the NHC-Ru catalyst system that realizes the chemo-selective transformation of ketones with methanol.By simply changing the base,a broad range of structurally diverse ketones,could be selectively and efficiently converted to the correspondingβ-methylated secondary alcohols or secondary alcohols.Remarkably,this catalytic system was very effective for the synthesis of bio-related molecules and deuterated alcohols,as well as the three-component coupling between methyl ketones,primary alcohols,and methanol.The reaction mechanism was further revealed by experiment and DFT mechanistic investigations.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
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
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
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
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
Oxygen evolution reaction(OER)is the dominant step for plenty of energy conversion and storage technologies.However,the OER suffers from sluggish kinetics and high overpotential due to its complex 4‐electron/proton t...Oxygen evolution reaction(OER)is the dominant step for plenty of energy conversion and storage technologies.However,the OER suffers from sluggish kinetics and high overpotential due to its complex 4‐electron/proton transfer mechanism.Thus,developing efficient electrocatalysts is particularly urgent to accelerate OER catalysis but still remains a great challenge.Herein,we have synthesized the novel cobalt molybdate nanoflakes(CoMoO_(4)‐O_(v)‐n@GF)with adjustable oxygen vacancies contents by in situ constructing CoMoO_(4) nanoflakes on graphite felt(GF)and annealing treatment under the reduction atmosphere.The best‐performing CoMoO_(4)‐O_(v)‐2@GF with optimal oxygen vacancies content shows splendid electrocatalytic performance with the low overpotential(296 mV at 10 mA cm^(‒2))and also small Tafel slope(62.4 mV dec^(‒1))in alkaline solution,which are comparable to those of the RuO_(2)@GF.The experimental and the density functional theory calculations results reveal that the construction of optimal oxygen vacancies in CoMoO_(4) can expose more active sites,narrow the band‐gap to increase the electrical conductivity,and modulate the free energy of the OER‐related intermediates to accelerate OER kinetics,thus improving its intrinsic activity.展开更多
Polypropylene(PP)scaffolds are the most commonly used biomedical scaffolds despite their disadvan-tages,which include problems with adhesion,infection,and inflammatory responses.Here,we report on the successful develo...Polypropylene(PP)scaffolds are the most commonly used biomedical scaffolds despite their disadvan-tages,which include problems with adhesion,infection,and inflammatory responses.Here,we report on the successful development of a facile one-step method to fabricate a series of novel triclosan poly-dopamine polypropylene(TPP)composite scaffolds and thereby effectively improve the biocompatibility and long-term antibacterial properties of PP scaffolds.The antibacterial triclosan can effectively interact with dopamine during biocompatible polydopamine formation on the PP scaffold by one-step green fab-rication.Thanks to the sustained release of triclosan from the biocompatible polydopamine coating,a 5mm×5mm sample of TPP-coated scaffold made with a triclosan concentration of 8 mg-mL^(-1)(referredto herein as TPP-8)exhibited a continuous antibacterial effect against both Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)for more than 15d,at maximum antibacterial volumes of 2 and 5mL,respectively.Our study establishes a new direction for facile long-term antibacterial studies for medical applications.展开更多
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Osteosarcoma is a malignant tumor originating from bone tissue that progresses rapidly and has a poor patient prognosis.Immunotherapy has shown great potential in the treatment of osteosarcoma.However,the immunosuppressive microenvironment severely limits the efficacy of osteosarcoma treatment.The dual pH-sensitive nanocarrier has emerged as an effective antitumor drug delivery system that can selectively release drugs into the acidic tumor microenvironment.Here,we prepared a dual pH-sensitive nanocarrier,loaded with the photosensitizer Chlorin e6(Ce6)and CD47 monoclonal antibodies(aCD47),to deliver synergistic photodynamic and immunotherapy of osteosarcoma.On laser irradiation,Ce6 can generate reactive oxygen species(ROS)to kill cancer cells directly and induces immunogenic tumor cell death(ICD),which further facilitates the dendritic cell maturation induced by blockade of CD47 by aCD47.Moreover,both calreticulin released during ICD and CD47 blockade can accelerate phagocytosis of tumor cells by macrophages,promote antigen presentation,and eventually induce T lymphocyte-mediated antitumor immunity.Overall,the dual pH-sensitive nanodrug loaded with Ce6 and aCD47 showed excellent immune-activating and anti-tumor effects in osteosarcoma,which may lay the theoretical foundation for a novel combination model of osteosarcoma treatment.
基金Guangzhou Key R&D Program/Plan Unveiled Flagship Project,Grant/Award Number:20220602JBGS02Guangzhou Basic and Applied Basic Research Project,Grant/Award Number:202201011449+3 种基金Research Fund Program of Guangdong Provincial Key Laboratory of Fuel Cell Technology,Grant/Award Numbers:FC202220,FC202216Guangdong Basic and Applied Basic Research Foundation,Grant/Award Numbers:2021A1515010167,2022A1515011196National Natural Science Foundation of China,Grant/Award Numbers:21975292,21978331,22068008,52101186Training Program of the Major Research Plan of the National Natural Science Foundation of China,Grant/Award Number:92061124。
文摘Remarkable progress has characterized the field of electrocatalysis in recent decades,driven in part by an enhanced comprehension of catalyst structures and mechanisms at the nanoscale.Atomically precise metal nanoclusters,serving as exemplary models,significantly expand the range of accessible structures through diverse cores and ligands,creating an exceptional platform for the investigation of catalytic reactions.Notably,ligand‐protected Au nanoclusters(NCs)with precisely defined core numbers offer a distinct advantage in elucidating the correlation between their specific structures and the reaction mechanisms in electrocatalysis.The strategic modulation of the fine microstructures of Au NCs presents crucial opportunities for tailoring their electrocatalytic performance across various reactions.This review delves into the profound structural effects of Au NC cores and ligands in electrocatalysis,elucidating their underlying mechanisms.A detailed exploration of the fundamentals of Au NCs,considering core and ligand structures,follows.Subsequently,the interaction between the core and ligand structures of Au NCs and their impact on electrocatalytic performance in diverse reactions are examined.Concluding the discourse,challenges and personal prospects are presented to guide the rational design of efficient electrocatalysts and advance electrocatalytic reactions.
基金supported by the National Natural Science Foundation of China(NSFC,Nos.22002023,21973113,21977019)the Guangdong Natural Science Funds for Distin-guished Young Scholar(No.2015A030306027)+1 种基金the Tip-top Youth Talents of Guangdong special support program(No.20153100042090537)the Fundamental Research Funds for the Central Universities。
文摘Herein,we report the NHC-Ru catalyst system that realizes the chemo-selective transformation of ketones with methanol.By simply changing the base,a broad range of structurally diverse ketones,could be selectively and efficiently converted to the correspondingβ-methylated secondary alcohols or secondary alcohols.Remarkably,this catalytic system was very effective for the synthesis of bio-related molecules and deuterated alcohols,as well as the three-component coupling between methyl ketones,primary alcohols,and methanol.The reaction mechanism was further revealed by experiment and DFT mechanistic investigations.
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.
文摘Oxygen evolution reaction(OER)is the dominant step for plenty of energy conversion and storage technologies.However,the OER suffers from sluggish kinetics and high overpotential due to its complex 4‐electron/proton transfer mechanism.Thus,developing efficient electrocatalysts is particularly urgent to accelerate OER catalysis but still remains a great challenge.Herein,we have synthesized the novel cobalt molybdate nanoflakes(CoMoO_(4)‐O_(v)‐n@GF)with adjustable oxygen vacancies contents by in situ constructing CoMoO_(4) nanoflakes on graphite felt(GF)and annealing treatment under the reduction atmosphere.The best‐performing CoMoO_(4)‐O_(v)‐2@GF with optimal oxygen vacancies content shows splendid electrocatalytic performance with the low overpotential(296 mV at 10 mA cm^(‒2))and also small Tafel slope(62.4 mV dec^(‒1))in alkaline solution,which are comparable to those of the RuO_(2)@GF.The experimental and the density functional theory calculations results reveal that the construction of optimal oxygen vacancies in CoMoO_(4) can expose more active sites,narrow the band‐gap to increase the electrical conductivity,and modulate the free energy of the OER‐related intermediates to accelerate OER kinetics,thus improving its intrinsic activity.
基金support from the project of the Science and Technology Program of Guangzhou(201704020059 and 201803010074).
文摘Polypropylene(PP)scaffolds are the most commonly used biomedical scaffolds despite their disadvan-tages,which include problems with adhesion,infection,and inflammatory responses.Here,we report on the successful development of a facile one-step method to fabricate a series of novel triclosan poly-dopamine polypropylene(TPP)composite scaffolds and thereby effectively improve the biocompatibility and long-term antibacterial properties of PP scaffolds.The antibacterial triclosan can effectively interact with dopamine during biocompatible polydopamine formation on the PP scaffold by one-step green fab-rication.Thanks to the sustained release of triclosan from the biocompatible polydopamine coating,a 5mm×5mm sample of TPP-coated scaffold made with a triclosan concentration of 8 mg-mL^(-1)(referredto herein as TPP-8)exhibited a continuous antibacterial effect against both Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)for more than 15d,at maximum antibacterial volumes of 2 and 5mL,respectively.Our study establishes a new direction for facile long-term antibacterial studies for medical applications.
