生物相容性Fe3O4@SiO2纳米粒子的合成及性能

背景:Fe3O4纳米粒子具有良好的磁学特性,SiO2具有良好的生物相容性,Fe3O4@SiO2复合纳米粒子有望成为靶向治疗的载体。目的:采用反相微乳液法合成生物相容性的Fe3O4@SiO2纳米粒子。方法:首先,以FeCl3?6H2O、FeCl2?4H2O、油酸、氨水等为原料,采用一壶化学共沉淀法合成油酸修饰的疏水性Fe3O4纳米粒子。随后,将油酸包裹的Fe3O4纳米粒子分散于环己烷中,然后将Triton-X100、正己醇及水在搅拌条件下加入到上述溶液,形成稳定的反相微乳液;在反相微乳液中,以氨水为催化剂,使正硅酸四乙酯水解、缩合,从而获得Fe3O4@SiO2复合纳米粒子。结果与结论:①透射电镜、X射线衍射显示:采用一壶化学沉淀法合成的Fe3O4具有尖晶石结构,平均粒径约为3.5nm;微乳液法能将SiO2成功包覆于Fe3O4表面,形成平均粒径为40nm的均一Fe3O4@SiO2复合纳米粒子。②磁性能分析显示:Fe3O4纳米粒子包裹后饱和磁化强度下降,但包裹前后矫顽力趋于零,均显示超顺磁性。③MTT结果显示纳米粒子与人脐静脉细胞融合细胞(EA.hy926)共培养24h时Fe3O4@SiO2组吸光度高于对照组(P<0.05);细胞培养48,72h,两组比较差异无显著性意义(P>0.05)。结果表明经反相微乳液法合成的Fe3O4@SiO2纳米粒子是一种优良的生物材料,其具有稳定、易分散及超顺磁性等特性。     

Adsorption mechanism of polyethyleneimine modified magnetic core–shell Fe3O4@SiO2 nanoparticles for anionic dye removal

In this paper, polyethyleneimine modified magnetic core–shell Fe₃O₄@SiO₂ nanoparticles (Fe₃O₄@SiO₂/PEI) were innovatively synthesized and investigated using various techniques such as TEM, TGA, FT-IR, XRD, VSM and XPS. The adsorption performance based on the removal of the anionic dyes Methyl orange and Congo red from aqueous solution was studied systematically. The results showed that the adsorption rate of anionic dyes MO and CR increased rapidly then decreased gradually as the pH increased, the adsorption capacity of Fe₃O₄@SiO₂/PEI for MO was better than that for CR, and the maximum adsorption capacity for MO and CR was 231.0 mg g⁻¹ at pH 4 and 134.6 mg g⁻¹ at pH 6, respectively. The equilibrium adsorption capacities for MO and CR increased rapidly in the initial 40 min, and reached equilibrium in approximately 180 min, while the adsorption capacity for MB was relative low even negligible, demonstrating the strong adsorptive affinity of Fe₃O₄@SiO₂/PEI toward anionic compounds. Both of the adsorption processes followed the pseudo-second-order kinetics model and the Freundlich isotherm model. The mechanism of adsorption was mainly related to electrostatic attraction and the number of active sites occupied by anionic dyes. This study provides valuable guidance and is an effective method for the removal of anionic dyes from aquatic environments.

In this paper, polyethyleneimine modified magnetic core–shell Fe₃O₄@SiO₂ nanoparticles (Fe₃O₄@SiO₂/PEI) were innovatively synthesized and investigated using various techniques such as TEM, TGA, FT-IR, XRD, VSM and XPS.     

Fe3O4磁性微粒的制备及表征

背景:磁性微粒作为一种磁性载体在固定化酶、免疫检测、靶向载药治疗及细胞分离等生物医学领域得到了广泛的应用.目的:制备分散稳定性好,相对磁性强的纳米级Fe3O4微粒.方法:以氯化亚铁、氯化铁、氢氧化钠为主要原料,采用化学共沉淀法合成Fe3O4磁性粒子.结果与结论:用正交设计法优化了Fe3O4微粒的合成工艺条件,得到制备Fe3O4粒子的最佳实验条件为Fe2+/Fe3+的物质的量之比为2∶1、共沉淀时的pH值为11、熟化温度为90 ℃、表面活性剂聚乙二醇的用量为40 mL,此时制得的Fe3O4粒子粒径最小,为78 nm,Fe3O4溶液的分散稳定性最好,相对磁性最强.从Fe3O4的扫描电镜图可以看出,Fe3O4微粒晶体颗粒为纳米级.     

Preparation of 5-hydroxymethylfurfural using magnetic Fe3O4@SiO2@mSiO2-TaOPO4 catalyst in 2-pentanol

5-Hydroxymethylfurfural (HMF) is one of the most important platform molecules and could be transformed into a variety of fuel additives and high value-added chemicals. Multiple catalyst systems have been developed for the conversion of carbohydrates to HMF, but there are still unavoidable problems, including high temperature and pressure, difficult recovery of solvent, corrosion of equipment, poor catalyst circulation, etc. Herein, a new magnetic Fe₃O₄@SiO₂@mSiO₂-TaOPO₄ catalyst for the preparation of HMF from fructose in 2-pentanol was developed. The structures of the catalysts were characterized by FT-IR, TSM, EDS, SEM, XRD and VSM. The 2-pentanol solvent is not only conducive to the production of HMF, but also enables the reaction to be carried out at a lower pressure. The highest yield of HMF (85.4%) was obtained using 20 wt% catalyst under 10% substrate concentration (0.5 g of fructose) at 120 °C for 3 h. The catalysts can be easily separated by magnetism. The slight decrease in catalyst activity after 7 cycles was mainly due to the loss of catalyst during the cycle operation. Simultaneously, the total yield of HMF was 51.3% after scale-up to 15 g of fructose, showing the possible industrial application potential of this catalyst system.

A novel magnetic core–shell mesoporous nanocomposite loaded with amorphous tantalum phosphate (Fe₃O₄@SiO₂@mSiO₂-TaOPO₄) was prepared and used as a catalyst for preparing HMF.     

Effect of Ni/Co mass ratio and NiO–Co3O4 loading on catalytic performance of NiO–Co3O4/Nb2O5–TiO2 for direct synthesis of 2-propylheptanol from n-valeraldehyde

In the direct synthesis of 2-propylheptanol (2-PH) from n-valeraldehyde, a second-metal oxide component Co₃O₄ was introduced into NiO/Nb₂O₅–TiO₂ catalyst to assist in the reduction of NiO. In order to optimize the catalytic performance of NiO–Co₃O₄/Nb₂O₅–TiO₂ catalyst, the effects of the Ni/Co mass ratio and NiO–Co₃O₄ loading were investigated. A series of NiO–Co₃O₄/Nb₂O₅–TiO₂ catalysts with different Ni/Co mass ratios were prepared by the co-precipitation method and their catalytic performances were evaluated. The result showed that NiO–Co₃O₄/Nb₂O₅–TiO₂ with a Ni/Co mass ratio of 8/3 demonstrated the best catalytic performance because the number of d-band holes in this catalyst was nearly equal to the number of electrons transferred in hydrogenation reaction. Subsequently, the NiO–Co₃O₄/Nb₂O₅–TiO₂ catalysts with different Ni/Co mass ratios were characterized by XRD and XPS and the results indicated that both an interaction of Ni with Co and formation of a Ni–Co alloy were the main reasons for the reduction of NiO–Co₃O₄/Nb₂O₅–TiO₂ catalyst in the reaction process. A higher NiO–Co₃O₄ loading could increase the catalytic activity but too high a loading resulted in incomplete reduction of NiO–Co₃O₄ in the reaction process. Thus the NiO–Co₃O₄/Nb₂O₅–TiO₂ catalyst with a Ni/Co mass ratio of 8/3 and a NiO–Co₃O₄ loading of 14 wt% showed the best catalytic performance; a 2-PH selectivity of 80.4% was achieved with complete conversion of n-valeraldehyde. Furthermore, the NiO–Co₃O₄/Nb₂O₅–TiO₂ catalyst showed good stability. This was ascribed to the interaction of Ni with Co, the formation of the Ni–Co alloy and further reservation of both in the process of reuse.

NiO–Co₃O₄/Nb₂O₅–TiO₂ catalyst with a Ni/Co mass ratio of 8/3 and NiO–Co₃O₄ loading of 14% shows the best catalytic performance.     

2D–2D ZnO/N doped g-C3N4 composite photocatalyst for antibiotics degradation under visible light

ZnO and g-C₃N₄ provide excellent photocatalytic properties for degradation of antibiotics in pharmaceutical wastewater. In this work, 2D–2D ZnO/N doped g-C₃N₄ (NCN) composite photocatalysts were prepared for degradation of tetracycline (TC), ciprofloxacin (CIP) and ofloxacin (OFLX). The addition of ZnO resulted in higher separation efficiency and lower recombination rate of photogenerated charge under visible light. The composite photocatalyst showed better degradation performance compared to ZnO or NCN alone. The TC degradation reached 81.3% in 15 minutes by applying the prepared 20% ZnO/NCN composite photocatalyst, showing great competitiveness among literature reported g-C₃N₄ based photocatalysts. After 30 minutes, the degradation rate of TC, CIP and OFLX reached 82.4%, 64.4% and 78.2%, respectively. The TC degradation constant of the composite photocatalyst was 2.7 times and 6.4 times higher than NCN and CN, respectively. Radical trapping experiments indicated that ·O₂⁻ was the dominant active substance. The transference of excited electrons from the conduction band (CB) of NCN to ZnO enhanced the separation of photogenerated electron–hole pairs and simultaneously suppressed their recombination. This study provides a possibility for the design of high-performance photocatalysts for antibiotics degradation in wastewater.

2D–2D ZnO/N doped g-C₃N₄ (NCN) composite photocatalysts were prepared for degradation of antibiotics with high efficiency.     

Preparation and properties of CF–Fe3O4–BN composite electromagnetic wave-absorbing materials

A three-layered electromagnetic (EM) wave-absorbing material was prepared by depositing a Fe₃O₄ and boron nitride (BN) coating onto the surface of a carbon fiber (CF) by in situ hybridization. The structure, chemical composition, morphology, high-temperature resistance, EM characteristics and EM wave absorption of the composite materials were analyzed. The composite materials contained CFs, and Fe₃O₄ was distributed along the axial direction of the fiber, whereas BN was found in the outermost coating layer. The proposed preparation method improved the oxidation resistance and EM wave absorption of CF. When the solubility of the metal salt was 20 g/100 ml, the decomposition temperature of the prepared CF/Fe₃O₄(3)/BN increased by more than 200 °C compared with that of CF/Fe₃O₄(3). The EM wave loss of less than −5 dB ranged within 8.8–18 GHz, and the effective EM wave-absorbing bandwidth (R < −10 dB) was 4.2 GHz (11.2–15.4 GHz). The prepared CF-based composite material had a lightweight structure, wide absorption band, and strong oxidation resistance. All these findings can serve as a reference for the study of other EM wave-absorbing materials.

A three-layered electromagnetic (EM) wave-absorbing material was prepared by depositing a Fe₃O₄ and boron nitride (BN) coating onto the surface of a carbon fiber (CF) by in situ hybridization.     

Synthesis and characterization of magnetic mesoporous Fe3O4@mSiO2–DODGA nanoparticles for adsorption of 16 rare earth elements

In this study, novel magnetic mesoporous Fe₃O₄@mSiO₂–DODGA nanoparticles were prepared for efficiently adsorbing and recycling REEs. Fe₃O₄@mSiO₂–DODGA was characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). The adsorption behavior of Fe₃O₄@mSiO₂–DODGA was investigated by ICP-OES. The results showed that the content of DODGA in the adsorbent was 367 μmol g⁻¹. Fe₃O₄@mSiO₂–DODGA exhibited the highest adsorption rates for 15 REEs, except Tm, in a 2 mol L⁻¹ nitric acid solution. Among these elements, the adsorption rates for Nd, Sm, Eu, Dy, Ho, Yb, Lu, Y and Sc ranged from 85.1% to 100.1%. The desorption rates for all 16 REE ions reached their maximum values when 0.01 mol L⁻¹ EDTA was used as the eluent. The desorption rates for Nd, Ce, Sm, Eu, Ho, Yb, Lu, Y, and Sc were 87.7–99.8%. Fe₃O₄@mSiO₂–DODGA had high stability in 2 mol L⁻¹ HNO₃ and could be used five times without significant loss of adsorption capacity. Moreover, these nanoparticles had high selectivity, and their adsorption rate was not affected even in a high-concentration solution of a coexisting ion. Therefore, 8 REE ions (Nd, Sm, Eu, Ho, Yb, Lu, Y, and Sc) were selected for the study of adsorption kinetics and adsorption isotherm experiments. It was demonstrated that the values of Q_e (equilibrium adsorption capacity) for Nd, Sm, Eu, Ho, Yb, Lu, Y, and Sc were 14.28–60.80 mg g⁻¹. The adsorption of REEs on Fe₃O₄@mSiO₂–DODGA followed the pseudo-second-order kinetic model, Elovich model and Langmuir isotherm model, which indicated that the adsorption process of Fe₃O₄@mSiO₂–DODGA for REEs comprised single-layer adsorption on a non-uniform surface controlled by chemical adsorption. It was concluded that Fe₃O₄@mSiO₂–DODGA represents a new material for the adsorption of REEs in strongly acidic solutions.

The high selectivity magnetic mesoporous Fe₃O₄@mSiO₂–DODGA nanomaterials were prepared for adsorption of 16 rare earth elements.     

Novel mesoporous Co3O4–Sb2O3–SnO2 active material in high-performance capacitive deionization

Capacitive deionization (CDI), as an emerging eco-friendly electrochemical brackish water deionization technology, has widely benefited from carbon/metal oxide composite electrodes. However, this technique still requires further development of the electrode materials to tackle the ion removal capacity/rate issues. In the present work, we introduce a novel active carbon (AC)/Co₃O₄–Sb₂O₃–SnO₂ active material for hybrid electrode capacitive deionization (HECDI) systems. The structure and morphology of the developed electrodes were determined using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Brunauer–Emmett–Teller (BET)/Barrett–Joyner–Halenda (BJH) techniques, as well as Fourier-transform infrared (FT-IR) spectroscopy. The electrochemical properties were also investigated by cyclic voltammetry (CV) and impedance spectroscopy (EIS). The CDI active materials AC/Co₃O₄ and AC/Co₃O₄–Sb₂O₃–SnO₂ showed a high specific capacity of 96 and 124 F g⁻¹ at the scan rate of 10 mV s⁻¹, respectively. In addition, the newly-developed electrode AC/Co₃O₄–Sb₂O₃–SnO₂ showed high capacity retention of 97.2% after 2000 cycles at 100 mV s⁻¹. Moreover, the electrode displayed excellent CDI performance with an ion removal capacity of 52 mg g⁻¹ at the applied voltage of 1.6 V and in a solution of potable water with initial electrical conductivity of 950 μs cm⁻¹. The electrode displayed a high ion removal rate of 7.1 mg g⁻¹ min⁻¹ with an excellent desalination–regeneration capability while retaining about 99.5% of its ion removal capacity even after 100 CDI cycles.

Capacitive deionization (CDI), as an emerging eco-friendly electrochemical brackish water deionization technology, has widely benefited from carbon/metal oxide composite electrodes.     

Cd-doped Ag2O/BiVO4 visible light Z-scheme photocatalyst for efficient ciprofloxacin degradation

Foreign element doping can produce new photocatalysts with different band edge positions and adsorption properties. A composite of such a doped semiconductor with another component should enhance its photocatalytic properties towards a target substrate. The present investigation used a simple hydrothermal protocol to prepare Cd-doped Ag₂O nanoparticles. The Cd-doping of Ag₂O nanoparticles changed its valence band maximum position from 0.8 eV (for undoped Ag₂O nanoparticles) to 2.67 eV with a slight narrowing of the Ag₂O bandgap. A combination of DFT calculation and XRD results showed that the dopant Cd substituted Ag in the Ag₂O lattice. The doped material is an effective photocatalyst for ciprofloxacin degradation but with poor recyclability. The joining of a BiVO₄ part to the Cd-doped Ag₂O nanostructures gave a composite with improved photocatalytic activity and recyclability towards ciprofloxacin degradation. DFT calculations showed that BiVO₄ has a higher oxygen affinity than Cd-doped Ag₂O. The XPS characterization of the composite and appropriate active species scavenger experiments demonstrated a Z-scheme mechanism. Superoxide radicals play a critical role in CIP degradation.

Foreign element doping can produce new photocatalysts with different band edge positions and adsorption properties.     

Application of pea-like yolk–shell structured Fe3O4@TiO2 nanosheets for photocatalytic and photo-Fenton oxidation of bisphenol-A

Uniform pea-like yolk–shell (PLYS) structured magnetic TiO₂(PLYS-Fe₃O₄@TiO₂) nanosheets have been prepared via a combined kinetics-controlled mechanical force-driven and hydrothermal etching assisted crystallization method and characterized. The resulting PLYS-Fe₃O₄@TiO₂ nanosheets possess well defined yolk–shell structures with a large BET surface area (∼187.26 m² g⁻¹) and a strong magnetic susceptibility (∼17.4 emu g⁻¹). The reaction rate constant was 24.2 × 10⁻² min⁻¹ as a result of oxidative decomposition of BPA using UV/PLYS-Fe₃O₄@TiO₂/H₂O₂ system. This is 1.1 and 8.34 times faster than the BPA decomposition reaction rate constant in UV/TiO₂/H₂O₂ and UV/Fe₃O₄/H₂O₂ systems, respectively. The synthesized catalyst also exhibited excellent recycle capability and excellent acid decomposition performance.

Uniform pea-like yolk–shell (PLYS) structured magnetic TiO₂(PLYS-Fe₃O₄@TiO₂) nanosheets have been prepared via a combined kinetics-controlled mechanical force-driven and hydrothermal etching assisted crystallization method and characterized.     

Preparation of Ag3PO4/α-Fe2O3 hybrid powders and their visible light catalytic performances

The inefficiency of conventional photocatalytic treatment for removing rhodamine B is posing potential risks to ecological environments. Here, we construct a highly efficient photocatalyst consisting of Ag₃PO₄ and α-Fe₂O₃ hybrid powders for the treatment of rhodamine B. Ag₃PO₄ nanoparticles (nanoparticles, about 50 nm) are uniformly dispersed on the surface of α-Fe₂O₃ microcrystals (hexagonal sheet, about 1.5 μm). The Ag₃PO₄-deposited uniformity on the α-Fe₂O₃ surface first increased, then decreased on increasing the hybrid ratio of Ag₃PO₄ to α-Fe₂O₃. When the hybrid ratio of Ag₃PO₄ to α-Fe₂O₃ is 1 : 2, the distribution of Ag₃PO₄ particles on the sheet α-Fe₂O₃ is more uniform with excellent Ag₃PO₄/α-Fe₂O₃ interface performance. The catalytic degradation efficiency of hybrids with the introduction of Ag₃PO₄ nanoparticles on the α-Fe₂O₃ surface reached 95%. More importantly, the hybrid material exhibits superior photocatalytic stability. Ag₃PO₄/α-Fe₂O₃ hybrids have good reusability, and the photocatalytic efficiency could still reach 72% after four reuses. The excellent photocatalytic activity of the as-prepared hybrids can be attributed to the heterostructure between Ag₃PO₄ and α-Fe₂O_3, which can effectively inhibit the photoelectron–hole recombination and broaden the visible light response range.

We construct a highly efficient photocatalyst consisting of Ag₃PO₄ and α-Fe₂O₃ hybrid powders for the treatment of rhodamine B. The catalytic degradation efficiency reached 95% after 10 min.     

Preparation and characterization of novel polyoxometalate/CoFe2O4/metal–organic framework magnetic core–shell nanocomposites for the rapid removal of organic dyes from water

In this study, the MIL-101(Cr) metal–organic framework was functionalized with a Dowson-type polyoxometalate (P₂W₁₈O₆₂⁶⁻; POM) and magnetic spinel cobalt ferrite (CoFe₂O₄; CFO) through a hydrothermal route and was characterized by means of FT-IR, XRD, FE-SEM, EDX, BET, and VSM measurements. All analyses confirmed the successful encapsulation of POM (∼32.2 wt%) into the magnetic MIL-101(Cr) framework. Compared to the pristine MIL-101(Cr) MOF, the as-prepared magnetic ternary nanocomposite (abbreviated as POM/CFO/MIL-101(Cr)) demonstrated a notable decrease in both the surface area and pore volume because of the incorporation of CoFe₂O₄ nanoparticles and huge P₂W₁₈O₆₂⁶⁻ polyanions into the cages of the MIL-101(Cr) framework. The POM/CFO/MIL-101(Cr) was then applied as a magnetically separable adsorbent for the rapid elimination of rhodamine B (RhB), methyl orange (MO), and methylene blue (MB) dye pollutants from aqueous solutions. For achieving the optimized conditions, the effects of initial pH, initial dye concentration, temperature, salt effect, and adsorbent dose on MB and RhB elimination were investigated. The dye adsorption isotherms followed the Langmuir model and pseudo-second-order kinetic model. The POM/CFO/MIL-101(Cr) composite material not only exhibited a fast adsorption rate towards dye molecules, but also demonstrated the selective adsorption of the cationic dyes in wastewater. The recycling experiments also demonstrated that the POM/CFO/MIL-101(Cr) adsorbent was highly stable and could be quickly recovered under a magnetic field without any alteration in the structure. The high adsorption capacity, simple fabrication method, rapid separation by a magnet and supreme reusability of the POM/CFO/MIL-101(Cr) nanocomposite make it an attractive adsorbent for the elimination of cationic dyes from wastewater.

The magnetic CoFe₂O₄/MIL-101 (Cr) metal–organic framework nanocomposite containing P₂W₁₈O₆₂⁶⁻ polyoxometalate was fabricated and applied as an ultrafast adsorbent to remove organic dyes from water.     

Preparation and performance study of a reactive polyurethane hot-melt adhesive/CS–Fe3O4 magnetic nanocomposite film/fabric

Magnetic nanoparticles are attracting significant attention for their wide application as biomaterials and magnetic storage materials. As an environmentally friendly adhesive, reactive polyurethane hot-melt adhesive (PUR) is a biocompatible polymer with a wide range of applications. In this paper, chitosan (CS)-surface-modified magnetic Fe₃O₄ nanoparticles were synthesized by the sol–gel method. Surface modification of the Fe₃O₄ nanoparticles with CS enhanced their mechanical properties in PUR. The nanoparticles were characterized by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) analyses, while their surface morphology was elucidated using scanning electron microscopy (SEM) and projection electron microscopy (TEM) techniques. Subsequently, PUR/CS–Fe₃O₄ magnetic nanocomposite films were prepared using an in situ method, wherein different amounts of CS–surface-modified magnetic Fe₃O₄ nanoparticles were doped into the PUR and coated on the films. The thermal, UV resistance and mechanical properties of the PUR/CS–Fe₃O₄ magnetic nanocomposite films were investigated by TGA, UV spectrometer and tensile testing. CS–Fe₃O₄ nanoparticles were successfully prepared using the sol–gel method and CS to modify the surface of the Fe₃O₄ nanoparticles. The results show that the mechanical properties and UV resistance of PUR/CS–Fe₃O₄ magnetic nanocomposites are improved by almost 50%, so the constructed PUR/CS–Fe₃O₄ magnetic nanocomposites have good UV-resistant properties and mechanical properties. The as-synthesized CS–Fe₃O₄ magnetic nanocomposites show great potential for application to mechanical and textile development.

Magnetic nanoparticles are attracting significant attention for their wide application as biomaterials and magnetic storage materials. As an environmentally friendly adhesive, reactive polyurethane hot-melt adhesive is a biocompatible polymer with a range of applications.     

Preparation of α-Fe2O3/rGO composites toward supercapacitor applications

Reduced graphene oxide (rGO) integrated with iron oxide nanoparticles (α-Fe₂O₃/rGO) composites with different morphologies were successfully obtained through the in situ synthesis and mechanical agitation methods. It was found that the α-Fe₂O₃ was densely and freely dispersed on the rGO layer. By comparing electrochemical properties, the sheet-like α-Fe₂O₃/rGO composites demonstrate excellent electrochemical performance: the highest specific capacitance, and excellent cycling stability and rate capacity. The specific capacitance is 970 F g⁻¹ at a current density of 1 A g⁻¹ and the capacitance retention is 75% after 2000 cycles with the current density reaching 5 A g⁻¹. It is mainly due to the synergistic effect between the α-Fe₂O₃ and rGO, and the high conductivity of the rGO offers a fast channel for the movement of electrons.

Preparation of α-Fe₂O₃/rGO composites for supercapacitor application using in situ synthesis and a mechanical agitation method.     

3D web freestanding RuO2–Co3O4 nanowires on Ni foam as highly efficient cathode catalysts for Li–O2 batteries

The mechanism of Li–O₂ batteries is based on the reactions of lithium ions and oxygen, which hold a theoretical higher energy density of approximately 3500 W h kg⁻¹. In order to improve the practical specific capacity and cycling performance of Li–O₂ batteries, a catalytically active mechanically robust air cathode is required. In this work, we synthesized a freestanding catalytic cathode with RuO₂ decorated 3D web Co₃O₄ nanowires on nickel foam. When the specific capacity was limited at 500 mA h g⁻¹, the RuO₂–Co₃O₄/NiF had a stable cycling life of up to 122 times. The outstanding performance can be primarily attributed to the robust freestanding Co₃O₄ nanowires with RuO₂ loading. The unique 3D web nanowire structure provides a large surface for Li₂O₂ growth and RuO₂ nanoparticle loading, and the RuO₂ nanoparticles help to promote the round trip deposition and decomposition of Li₂O₂, therefore enhancing the cycling behavior. This result indicates the superiority of RuO₂–Co₃O₄/NiF as a freestanding highly efficient catalytic cathode for Li–O₂ batteries.

Freestanding RuO₂–Co₃O₄ nanowires on Ni foam were synthesized and applied as a cathode in Li–O₂ battery. This cathode can deliver a high capacity of 9620 mA h g⁻¹ and stable long-term operation exceeding 122 cycles at 100 mA g⁻¹.     

A visible light active,carbon–nitrogen–sulfur co-doped TiO2/g-C3N4 Z-scheme heterojunction as an effective photocatalyst to remove dye pollutants

Heterojunction formation and heteroatom doping could be viewed as promising strategies for constructing composite photocatalysts with high visible light catalytic activity. In this work, we fabricated a carbon, nitrogen and sulfur co-doped TiO₂/g-C₃N₄ (CNS-TiO₂/g-C₃N₄) Z-scheme heterojunction photocatalyst composite via one-step hydrothermal and calcination methods. Compared with pure TiO₂ and g-C₃N₄, the CNS-TiO₂/g-C₃N₄ Z-scheme heterojunction photocatalyst possessed excellent degradation performance under visible light irradiation. Due to the formation of the Z-scheme heterostructure, the utilization rate of the photogenerated electrons–holes generated by the catalyst was increased, which enhanced the catalytic activity. Moreover, the heteroatom doping (C, N and S) could efficiently tailor the band gap of TiO₂ and facilitate electron transition, contributing to enhancing the degradation ability under visible light. The CNS-TiO₂/g-C₃N₄-2 exhibited a superior photocatalytic degradation efficiency (k = 0.069 min⁻¹) for methyl orange dye (MO), which is higher than those of pure TiO₂ (k = 0.001 min⁻¹) and g-C₃N₄ (k = 0.012 min⁻¹), showing excellent photocatalytic activity against organic pollutants.

The CNS-TiO₂/g-C₃N₄ photocatalyst with excellent visible light catalytic activity was successfully manufactured, benefiting from the construction of the Z-scheme heterojunction and the co-doping of heteroatoms (C, N and S).     

Atomic layer deposition with rotary reactor for uniform hetero-junction photocatalyst,g-C3N4@TiO2 core–shell structures

A heterojunction of TiO₂ grown on g-C₃N₄ particles is demonstrated using atomic layer deposition (ALD), equipped with a specifically designed rotary reactor for maintaining stable mechanical dispersion of g-C₃N₄ particles during ALD. The photocatalytic activity of the g-C₃N₄@ALD-TiO₂ core–shell composites was examined using the degradation of rhodamine B dye under visible light irradiation. The optimal composite with 5 ALD cycles of TiO₂ exhibited the highest photocatalytic reaction rate constant among the composites with a range of ALD cycles from 2 to 200 cycles, which was observed to be 3 times higher than that of pristine g-C₃N₄ and 2 times higher than that of g-C₃N₄@TiO₂ composite prepared using a simple impregnation method. The ALD-TiO₂ were well-dispersed on the g-C₃N₄ surface, while TiO₂ nanoparticles were agglomerated onto the g-C₃N₄ in the g-C₃N₄@TiO₂ composite prepared by the impregnation method. This created uniform and stable heterojunctions between the g-C₃N₄ and TiO₂, thus, enhancing the photocatalytic activity.

A heterojunction of TiO₂ grown on g-C₃N₄ particles is demonstrated using atomic layer deposition (ALD), equipped with a specifically designed rotary reactor for maintaining stable mechanical dispersion of g-C₃N₄ particles during ALD.     

Visible-light photoelectrocatalysis/H2O2 synergistic degradation of organic pollutants by a magnetic Fe3O4@SiO2@mesoporous TiO2 catalyst-loaded photoelectrode

In this paper, we describe a method for photoelectrocatalysis (PEC)/H₂O₂ synergistic degradation of organic pollutants with a magnetic Fe₃O₄@SiO₂@mesoporous TiO₂ (FST) photocatalyst-loaded electrode. At optimal conditions of pH 3.0, 2.25% H₂O₂, working electrode (fixed FST 30 mg) potential +0.6 V (vs. SCE), and 10 mg L⁻¹ of all experimental pollutants, the FST PEC/H₂O₂ synergistic system exhibited high activity and stability for the removal of various organic pollutants under visible light with comparable degradation efficiencies, including MB (98.8%), rhodamine B (Rh B, 96.7%), methyl orange (MO, 97.7%), amoxicillin (AMX, 83.9%). Moreover, this system obtained TOC removal ratios of 83.5% (MB), 77.9% (Rh B), 80.2% (MO), 65.5% (AMX) within 8 min. The kinetic rate constants of the PEC/H₂O₂ synergistic system were nearly 53 and 1436 times higher than that of the PEC process and H₂O₂ photolysis under visible light, respectively. Furthermore, the main reactive oxidant species (˙OH, ˙O₂⁻) were studied and enhanced mechanisms of the photocatalytic-electro-H₂O₂ coupling system were proposed. This work brings new insights to efficiently purify organic pollutants by PEC coupled with peroxide under solar light illumination.

A visible-light PEC/H₂O₂ synergistic system based on Fe₃O₄@SiO₂@mesoporous TiO₂ photocatalysts was constructed. Reaction mechanisms during PEC/H₂O₂ coupling system were elucidated.     

血管生成靶向纳米粒子c（RGDyK）@SiO2@Fe3O4的合成及生物性能

背景:SiO2含有较多的羟基官能团,可进一步功能化而与靶向性配体相偶联,从而拓展Fe3O4@SiO2纳米粒子在生物医药领域的应用。目的:探讨靶向性纳米粒子c(RGDyK)@SiO2@Fe3O4)的合成方法,并对其性能进行测试。方法:采用一壶化学共沉淀法合成油酸修饰的疏水性Fe3O4纳米粒子,采用反相微乳液法合成生物相容性Fe3O4@SiO2复合纳米粒子;以3-氨丙基三乙氧基硅烷为偶联剂将复合粒子中SiO2表面的羟基氨基化、醛基化,加入1.0mgc(RGDyK)多肽,超声震荡下反应生成c(RGDyK)@SiO2@Fe3O4纳米粒子。将Fe3O4@SiO2或c(RGDyK)@SiO2@Fe3O4与人脐静脉细胞融合细胞(EA.hy926)共培养24,48,72h进行检测。结果与结论:实验合成的Fe3O4@SiO2复合纳米粒子的平均粒径为40nm,应用3-氨丙基三乙氧基硅烷可将c(RGDyK)成功耦合于复合粒子的SiO2表面。Fe3O4@SiO2或c(RGDyK)@SiO2@Fe3O4与EA.hy926共培养24h,EA.hy926细胞活性明显增高(P<0.05),以c(RGDyK)@SiO2@Fe3O4的作用更明显;共培养72h后,细胞活性在各组间差异无显著性意义(P>0.05)。电镜观察发现,EA.hy926细胞对靶向性c(RGDyK)@SiO2@Fe3O4粒子的吞噬能力明显强于非靶向性Fe3O4@SiO2粒子。说明实验合成的c(RGDyK)@SiO2@Fe3O4纳米粒子具有良好的生物相容性、超顺磁性及较高的血管内皮细胞靶向性,是一种优良的生物材料。