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
Fe_(3)O_(4)and Cu_(2)O were successively immobilized on alkali-treated straw,and the magnetically separable straw@Fe_(3)O_(4)/Cu_(2)O composite was obtained.The straw@Fe_(3)O_(4)/Cu_(2)O was characterized by Fourier t...Fe_(3)O_(4)and Cu_(2)O were successively immobilized on alkali-treated straw,and the magnetically separable straw@Fe_(3)O_(4)/Cu_(2)O composite was obtained.The straw@Fe_(3)O_(4)/Cu_(2)O was characterized by Fourier transform infrared spectroscopy,X-ray diffraction,scanning electron microscopy,X-ray photoelectron spectroscopy and vibrating sample magnetometry,respectively.Photocatalytic performance of the straw@Fe_(3)O_(4)/Cu_(2)O was evaluated by measuring the degradation of methyl orange(MO)under irradiation of visible light.The introduction of Fe3O4 not only endowed the straw@Fe_(3)O_(4)/Cu_(2)O with magnetic separation feature but also significantly enhanced photocatalytic activity because Fe3O4 could prevent recombination of hole-electron pairs.The active species capture experiment showed that holes(h+),hydroxyl(∙OH)and superoxide(∙O2ˉ)radicals all took part in the MO degradation.In addition,the photocatalytic mechanism of straw@Fe_(3)O_(4)/Cu_(2)O was proposed based on the experimental results.After five cycles for the photodegradation of MO,the straw@Fe_(3)O_(4)/Cu_(2)O still displayed good photocatalytic activity,suggesting that the as-prepared composite had great potential for practical use in wastewater treatment.展开更多
Novel magnetic nanoparticles(MNPs),Fe_(3)O_(4)@SiO_(2) and Fe_(3)O_(4)@SiO_(2)@PEG-(COOH)_(2),were prepared by loading different amounts of SiO_(2) or/and PEG-(COOH)_(2) onto Fe_(3)O_(4) nanoparticles,and their feasib...Novel magnetic nanoparticles(MNPs),Fe_(3)O_(4)@SiO_(2) and Fe_(3)O_(4)@SiO_(2)@PEG-(COOH)_(2),were prepared by loading different amounts of SiO_(2) or/and PEG-(COOH)_(2) onto Fe_(3)O_(4) nanoparticles,and their feasibility to be used as forward osmosis(FO)draw solutes was investigated.The characterization of the materials showed that,compared to normal Fe_(3)O_(4) nanoparticles,the modified MNPs exhibited enhanced dispersity and high osmotic pressure in aqueous solution.The FO experiment indicated that the synthesized draw solutes could obtain a water flux as high as 10 L·m^(-2)·h^(-1) with an aquaporin FO membrane.The optimal concentration of the added tetraethyl orthosilicate was 30%during the synthesis.The novel MNPs could be easily recovered from draw solutions by magnetic field,and the recovery rate of Fe_(3)O_(4)@SiO_(2) and Fe_(3)O_(4)@SiO_(2)@PEG-(COOH)_(2) was 83.95%and 63.37%,respectively.Moreover,after 5 recycles of reuse,the water flux of Fe_(3)O_(4)@SiO_(2) and Fe_(3)O_(4)@SiO_(2)@PEG-(COOH)_(2) as draw solutes still remained 64.36%and 85.26%,respectively.The experimental results demonstrated that the synthesized core–shell magnetic nanoparticles are promising draw solutes,and the Fe_(3)O_(4)@SiO_(2)@PEG-(COOH)_(2) was more suitable to be used as draw solute in FO process.展开更多
In this work,we reported a new strategy to improve the nonlinear saturable absorption performance of magnetite(Fe_(3)O_(4))nanoparticles(FONPs)via the compositional engineering with the Ti_(3)C_(2) MXene in the near-i...In this work,we reported a new strategy to improve the nonlinear saturable absorption performance of magnetite(Fe_(3)O_(4))nanoparticles(FONPs)via the compositional engineering with the Ti_(3)C_(2) MXene in the near-infrared(NIR)region.Based on the DFT simulation,the band structures and work function were significantly modified by the Ti_(3)C_(2) MXene doping.By using the open-aperture Z-scan technology,the nonlinear optical features of the FONPs@Ti_(3)C_(2) nanocomposite were significantly improved,showing the great potential as the saturable absorber in the pulsed laser.With the nanocomposite as the saturable absorber,the passively Q-switched Nd:GdVO4 lasers emitted much shorter pulse durations when compared with the pristine FONP saturable absorber.These findings indicated that FONPs@Ti_(3)C_(2) heterostructure was a promising saturable absorber for the short pulse generation in the NIR region.展开更多
Natural enzymes as biological catalysts possess remarkable advantages,especially their highly efficient and selective catalysis under mild conditions.However,most natural enzymes are proteins,thus exhibiting an inhere...Natural enzymes as biological catalysts possess remarkable advantages,especially their highly efficient and selective catalysis under mild conditions.However,most natural enzymes are proteins,thus exhibiting an inherent low durability to harsh reaction conditions.Artificial enzyme mimetics have been pursued extensively to avoid this drawback.Quite recently,some inorganic nanoparticles(NPs) have been found to exhibit unique enzyme mimetics.In addition,their much higher stability overcomes the inherent disadvantage of natural enzymes.Furthermore,easy mass-production and low cost endow them more benefits.As a new member of artificial enzyme mimetics,they have received intense attention.In this review article,major progress in this field is summarized and future perspectives are highlighted.展开更多
在病毒感染和癌症治疗中,干扰素α-2b(IFN-α2b)的灵敏检测至关重要,因此需要开发经济、稳定的灵敏检测IFN-α2b的方法.传统的酶联免疫吸附测定(ELISA)中使用的天然酶存在制备成本高和稳定性差等问题.为了提高其灵敏度并降低成本,我们...在病毒感染和癌症治疗中,干扰素α-2b(IFN-α2b)的灵敏检测至关重要,因此需要开发经济、稳定的灵敏检测IFN-α2b的方法.传统的酶联免疫吸附测定(ELISA)中使用的天然酶存在制备成本高和稳定性差等问题.为了提高其灵敏度并降低成本,我们合成了聚乙烯亚胺(PEI)修饰的四氧化三铁磁性纳米粒子(Fe_(3)O_(4)@PEI MNPs).在基于ELISA的IFN-α2b检测中,这些磁性纳米粒子作为辣根过氧化物酶的替代品,提供了比色谱和传统ELISA技术更高的灵敏度,并且能够实现IFN-α2b的可视化检测.该免疫分析方法的线性范围为0.075-25 ng mL^(-1),检测限为0.055 ng mL^(-1).基于Fe_(3)O_(4)@PEI MNPs优异的过氧化物酶活性,该方法在用于检测IFN-α2b和其他蛋白质生物标志物监测方面具有临床应用潜力.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.
基金Science and Technology Project from Ministry of Housing and Urban-Rural Development of the People’s Republic of China(No.2014-K7-007)。
文摘Fe_(3)O_(4)and Cu_(2)O were successively immobilized on alkali-treated straw,and the magnetically separable straw@Fe_(3)O_(4)/Cu_(2)O composite was obtained.The straw@Fe_(3)O_(4)/Cu_(2)O was characterized by Fourier transform infrared spectroscopy,X-ray diffraction,scanning electron microscopy,X-ray photoelectron spectroscopy and vibrating sample magnetometry,respectively.Photocatalytic performance of the straw@Fe_(3)O_(4)/Cu_(2)O was evaluated by measuring the degradation of methyl orange(MO)under irradiation of visible light.The introduction of Fe3O4 not only endowed the straw@Fe_(3)O_(4)/Cu_(2)O with magnetic separation feature but also significantly enhanced photocatalytic activity because Fe3O4 could prevent recombination of hole-electron pairs.The active species capture experiment showed that holes(h+),hydroxyl(∙OH)and superoxide(∙O2ˉ)radicals all took part in the MO degradation.In addition,the photocatalytic mechanism of straw@Fe_(3)O_(4)/Cu_(2)O was proposed based on the experimental results.After five cycles for the photodegradation of MO,the straw@Fe_(3)O_(4)/Cu_(2)O still displayed good photocatalytic activity,suggesting that the as-prepared composite had great potential for practical use in wastewater treatment.
文摘Novel magnetic nanoparticles(MNPs),Fe_(3)O_(4)@SiO_(2) and Fe_(3)O_(4)@SiO_(2)@PEG-(COOH)_(2),were prepared by loading different amounts of SiO_(2) or/and PEG-(COOH)_(2) onto Fe_(3)O_(4) nanoparticles,and their feasibility to be used as forward osmosis(FO)draw solutes was investigated.The characterization of the materials showed that,compared to normal Fe_(3)O_(4) nanoparticles,the modified MNPs exhibited enhanced dispersity and high osmotic pressure in aqueous solution.The FO experiment indicated that the synthesized draw solutes could obtain a water flux as high as 10 L·m^(-2)·h^(-1) with an aquaporin FO membrane.The optimal concentration of the added tetraethyl orthosilicate was 30%during the synthesis.The novel MNPs could be easily recovered from draw solutions by magnetic field,and the recovery rate of Fe_(3)O_(4)@SiO_(2) and Fe_(3)O_(4)@SiO_(2)@PEG-(COOH)_(2) was 83.95%and 63.37%,respectively.Moreover,after 5 recycles of reuse,the water flux of Fe_(3)O_(4)@SiO_(2) and Fe_(3)O_(4)@SiO_(2)@PEG-(COOH)_(2) as draw solutes still remained 64.36%and 85.26%,respectively.The experimental results demonstrated that the synthesized core–shell magnetic nanoparticles are promising draw solutes,and the Fe_(3)O_(4)@SiO_(2)@PEG-(COOH)_(2) was more suitable to be used as draw solute in FO process.
基金This work was finically supported by the National Natural Science Foundation of China(NSFC)(Nos.12004213 and 21872084)the Fundamental Research Fund of Shandong University(No.2018TB044)the financial support from the Young Scholar Program of Shandong University。
文摘In this work,we reported a new strategy to improve the nonlinear saturable absorption performance of magnetite(Fe_(3)O_(4))nanoparticles(FONPs)via the compositional engineering with the Ti_(3)C_(2) MXene in the near-infrared(NIR)region.Based on the DFT simulation,the band structures and work function were significantly modified by the Ti_(3)C_(2) MXene doping.By using the open-aperture Z-scan technology,the nonlinear optical features of the FONPs@Ti_(3)C_(2) nanocomposite were significantly improved,showing the great potential as the saturable absorber in the pulsed laser.With the nanocomposite as the saturable absorber,the passively Q-switched Nd:GdVO4 lasers emitted much shorter pulse durations when compared with the pristine FONP saturable absorber.These findings indicated that FONPs@Ti_(3)C_(2) heterostructure was a promising saturable absorber for the short pulse generation in the NIR region.
基金supported by the National Natural Science Foundation of China (Grant No. 20773032)the National Basic Research Program of China (Grant No. 2011CB932802)
文摘Natural enzymes as biological catalysts possess remarkable advantages,especially their highly efficient and selective catalysis under mild conditions.However,most natural enzymes are proteins,thus exhibiting an inherent low durability to harsh reaction conditions.Artificial enzyme mimetics have been pursued extensively to avoid this drawback.Quite recently,some inorganic nanoparticles(NPs) have been found to exhibit unique enzyme mimetics.In addition,their much higher stability overcomes the inherent disadvantage of natural enzymes.Furthermore,easy mass-production and low cost endow them more benefits.As a new member of artificial enzyme mimetics,they have received intense attention.In this review article,major progress in this field is summarized and future perspectives are highlighted.
基金financially supported by the National Key Research and Development Program of China(2019YFA0709202)the Natural Science Foundation of Jilin Province(20220101055JC)+1 种基金the International Cooperation Project of Jilin Scientific and Technological Development Program(20190701059GH)the Department of Science and Technology of Jilin Province(20220508098RC)。
文摘在病毒感染和癌症治疗中,干扰素α-2b(IFN-α2b)的灵敏检测至关重要,因此需要开发经济、稳定的灵敏检测IFN-α2b的方法.传统的酶联免疫吸附测定(ELISA)中使用的天然酶存在制备成本高和稳定性差等问题.为了提高其灵敏度并降低成本,我们合成了聚乙烯亚胺(PEI)修饰的四氧化三铁磁性纳米粒子(Fe_(3)O_(4)@PEI MNPs).在基于ELISA的IFN-α2b检测中,这些磁性纳米粒子作为辣根过氧化物酶的替代品,提供了比色谱和传统ELISA技术更高的灵敏度,并且能够实现IFN-α2b的可视化检测.该免疫分析方法的线性范围为0.075-25 ng mL^(-1),检测限为0.055 ng mL^(-1).基于Fe_(3)O_(4)@PEI MNPs优异的过氧化物酶活性,该方法在用于检测IFN-α2b和其他蛋白质生物标志物监测方面具有临床应用潜力.
