Two-dimensional(2D)metal organic frameworks(MOFs)are emerging as low-cost oxygen evolution reaction(OER)electrocatalysts,however,suffering aggregation and poor operation stability.Herein,ultrafine Fe_(3)O_(4) nanopart...Two-dimensional(2D)metal organic frameworks(MOFs)are emerging as low-cost oxygen evolution reaction(OER)electrocatalysts,however,suffering aggregation and poor operation stability.Herein,ultrafine Fe_(3)O_(4) nanoparticles(diameter:6±2 nm)are homogeneously immobilized on 2D Ni based MOFs(Ni-BDC,thickness:5±1 nm)to improve the OER stability.Electronic structure modulation for enhanced catalytic activity is studied via adjusting the amount of Fe_(3)O_(4) nanoparticles on Ni-BDC.The optimal Fe_(3)O_(4)/Ni-BDC achieves the best OER performance with an overpotential of 295 mV at 10 mA cm^(-2),a Tafel slope of 47.8 mV dec^(-1) and a considerable catalytic durability of more than 40 h(less than 5 h for Ni-BDC alone).DFT calculations confirm that the active sites for Fe_(3)O_(4)/Ni-BDC are mainly contributed by Fe species with a higher oxidation state,and the potential-determining step(PDS)is the formation of the adsorbed O*species,which are facilitated in the composite.展开更多
目的考察Fe_(3)O_(4)纳米颗粒在低频振动磁场(low-frequency vibrating magnetic field,VMF)驱动下通过磁场机械力杀伤肿瘤细胞的效果。方法通过共沉淀法合成一种磁性强、具有不规则形貌的立方相Fe_(3)O_(4)纳米颗粒。将其置于本课题组...目的考察Fe_(3)O_(4)纳米颗粒在低频振动磁场(low-frequency vibrating magnetic field,VMF)驱动下通过磁场机械力杀伤肿瘤细胞的效果。方法通过共沉淀法合成一种磁性强、具有不规则形貌的立方相Fe_(3)O_(4)纳米颗粒。将其置于本课题组自制的VMF中,研究其介导的磁场机械力对肿瘤细胞的杀伤效果。结果单纯施加VMF对细胞活力无影响;加入Fe_(3)O_(4)纳米颗粒后,细胞活力随VMF处理时间和Fe_(3)O_(4)纳米颗粒浓度的增加而降低,受损细胞释放的乳酸脱氢酶也随磁场处理时间延长而增加。结论不规则形貌Fe_(3)O_(4)纳米颗粒在VMF下可将机械力转移到肿瘤细胞,破坏细胞结构,导致细胞死亡;所采用的VMF装置结构简单、使用安全、操作方便。所采用的磁性粒子及其杀伤肿瘤细胞的方法,有临床转化潜力。展开更多
High magnetic protective fabrics with rare earth Nd doped Fe_(3)O_(4) nanoparticles were fabricated via a grafting method.The structure,crystal form,and elemental composition of nanoparticles were investigated by tran...High magnetic protective fabrics with rare earth Nd doped Fe_(3)O_(4) nanoparticles were fabricated via a grafting method.The structure,crystal form,and elemental composition of nanoparticles were investigated by transmission electron microscopy,energy dispersive X-ray,X-ray powder diffraction,and X-ray photoelectron spectroscopy.The obtained NdFe_(2)O_(4) nanoparticles show spherical shape with fine dispersion and reasonable element composition.However,they demonstrate fine superparamagnetic properties with a magnetic saturation value of 29.25 A·m^(2)/g and low coercivity of 1.902 mT through the vibrating sample magnetometry technique,which can be well developed in magnetic shielding protective applications.Then,the cotton fabrics with plain weave were finished by a proofing rapier loom as a carrier.The NdFe_(2)O_(4) nanoparticles underwent some appropriate surface modification and then were grafted onto the cotton fabrics by a bridge agent of N,N’-dissuccinimidyl carbonate.The morphology,structure,dispersion effect,and electromagnetic protective properties of the fabrics were observed through scanning electron microscopy,Fourier infrared spectroscopy,thermogravimetric analysisdifferential scanning calorimetry(TG-DSC),and a vector network analyzer.The reliable fabrics with grafting reaction on the interface are expected to have potential applications in the field of electromagnetic protection and biomedicine fields.展开更多
基金support from the Chinese Scholarship Council(201706220080)for W.H.the Natural Science Foundation of Hunan Province(2019JJ50526)for C.P.+1 种基金The Danish Council for Independent Research for the YDUN project(DFF 4093-00297)to J.Z.Villum Experiment(grant No.35844)for X.X.
文摘Two-dimensional(2D)metal organic frameworks(MOFs)are emerging as low-cost oxygen evolution reaction(OER)electrocatalysts,however,suffering aggregation and poor operation stability.Herein,ultrafine Fe_(3)O_(4) nanoparticles(diameter:6±2 nm)are homogeneously immobilized on 2D Ni based MOFs(Ni-BDC,thickness:5±1 nm)to improve the OER stability.Electronic structure modulation for enhanced catalytic activity is studied via adjusting the amount of Fe_(3)O_(4) nanoparticles on Ni-BDC.The optimal Fe_(3)O_(4)/Ni-BDC achieves the best OER performance with an overpotential of 295 mV at 10 mA cm^(-2),a Tafel slope of 47.8 mV dec^(-1) and a considerable catalytic durability of more than 40 h(less than 5 h for Ni-BDC alone).DFT calculations confirm that the active sites for Fe_(3)O_(4)/Ni-BDC are mainly contributed by Fe species with a higher oxidation state,and the potential-determining step(PDS)is the formation of the adsorbed O*species,which are facilitated in the composite.
文摘目的考察Fe_(3)O_(4)纳米颗粒在低频振动磁场(low-frequency vibrating magnetic field,VMF)驱动下通过磁场机械力杀伤肿瘤细胞的效果。方法通过共沉淀法合成一种磁性强、具有不规则形貌的立方相Fe_(3)O_(4)纳米颗粒。将其置于本课题组自制的VMF中,研究其介导的磁场机械力对肿瘤细胞的杀伤效果。结果单纯施加VMF对细胞活力无影响;加入Fe_(3)O_(4)纳米颗粒后,细胞活力随VMF处理时间和Fe_(3)O_(4)纳米颗粒浓度的增加而降低,受损细胞释放的乳酸脱氢酶也随磁场处理时间延长而增加。结论不规则形貌Fe_(3)O_(4)纳米颗粒在VMF下可将机械力转移到肿瘤细胞,破坏细胞结构,导致细胞死亡;所采用的VMF装置结构简单、使用安全、操作方便。所采用的磁性粒子及其杀伤肿瘤细胞的方法,有临床转化潜力。
基金Project supported by the Natural Science Foundation of Fujian Province(2020J01849)Major Science and Technology Project of Fuzhou(2021ZD298)+1 种基金Science and Technology Projects of Fujian Province(2021H0037)Research Project of the Fashu Foundation(MFK23004)。
文摘High magnetic protective fabrics with rare earth Nd doped Fe_(3)O_(4) nanoparticles were fabricated via a grafting method.The structure,crystal form,and elemental composition of nanoparticles were investigated by transmission electron microscopy,energy dispersive X-ray,X-ray powder diffraction,and X-ray photoelectron spectroscopy.The obtained NdFe_(2)O_(4) nanoparticles show spherical shape with fine dispersion and reasonable element composition.However,they demonstrate fine superparamagnetic properties with a magnetic saturation value of 29.25 A·m^(2)/g and low coercivity of 1.902 mT through the vibrating sample magnetometry technique,which can be well developed in magnetic shielding protective applications.Then,the cotton fabrics with plain weave were finished by a proofing rapier loom as a carrier.The NdFe_(2)O_(4) nanoparticles underwent some appropriate surface modification and then were grafted onto the cotton fabrics by a bridge agent of N,N’-dissuccinimidyl carbonate.The morphology,structure,dispersion effect,and electromagnetic protective properties of the fabrics were observed through scanning electron microscopy,Fourier infrared spectroscopy,thermogravimetric analysisdifferential scanning calorimetry(TG-DSC),and a vector network analyzer.The reliable fabrics with grafting reaction on the interface are expected to have potential applications in the field of electromagnetic protection and biomedicine fields.
