Mesoporous ZnFe2O4 Research Articles

Synthesis of mesoporous grooved ZnFe2O4 nanobelts as peroxidase mimetics for improved enzymatic biosensor

In this study, we developed a novel coelectrospinning technology to synthesize mesoporous grooved ZnFe2O4 nanobelts. The nanobelts have mesoporous thin wall, grooved belt style structured transport channels and peroxidase mimetics performance. They were employed to immobilize glucose oxidase enzyme for glucose biosensor and exhibited improved performance. The widely distributed mesopores afforded scale-adaptive cells to hold enzymes molecules and maintain enzymatic activity. The grooved thin walls made enzymes have high exposure to reactants and caused high catalysis efficiency. The nanobelts themselves catalyzed the intermediate product of enzyme catalysis to enhance biosensing performance. The prepared biosensor exhibited high sensitivity (112.1μAmM−1cm−2), fast response (<2s), low KM(app) (0.75mM) and well stability. Mesoporous grooved ZnFe2O4 nanobelts are promising material for enzymes assembly and biosensing applications.

Self-assembled three-dimensional mesoporous ZnFe2O4-graphene composites for lithium ion batteries with significantly enhanced rate capability and cycling stability

We report a facile, one-pot hydrothermal strategy to prepare self-assembled three-dimensional mesoporous ZnFe2O4 submicron-sized spheres wrapped in graphene sheets as high-performance anode material for lithium ion batteries. The mesoporous submicron-sized spheres are composed of numerous nanoparticles where the void spaces between the neighboring nanoparticles provide a cushion to alleviate volume variation issues during the conversion/alloying process and also provide large contact areas with the electrolyte to facilitate lithium ion diffusion and electron transport during cycling. The synergistic effects between ZnFe2O4 submicron-sized spheres and graphene sheets are another positive effect to enhance the electrochemical performance. The electrochemical characterization of ZnFe2O4-graphene composites exhibits a high specific capacity of 1182 mAh g−1 cycling at a specific current of 100 mA g−1, and significantly enhanced rate capability and cycling stability after long-term testing resulting from their unique structure features.

Rapid low-temperature synthesis of mesoporous nanophase ZnFe2O4with enhanced lithium storage properties for Li-ion batteries

In this work, a rapid low-temperature and cost-effective refluxing synthesis strategy was elegantly designed, and elaborately developed for high-yield fabrication of mesoporous nanocrystalline ZnFe2O4 with nano-scaled size of ∼7 nm, desirable mesoporosity and large specific surface area. Benefitting from these admirable nanostructured architectures, the as-derived nanophase ZnFe2O4 exhibited excellent discharge capacity of 1322 mA h g−1 on the first cycle, and showed outstanding cycling durability, rate capability, and coulombic efficiency even at high current rates when evaluated as an anode for Li-ion batteries. More importantly, a low temperature of 100 °C and short reaction time of 5 h were applied here; therefore, the efficient synthetic strategy we proposed herein is advocated for scaled-up commercial application.

Bio-inspired synthesis and characterization of mesoporous ZnFe2O4 hollow fibers with enhancement of adsorption capacity for acid dye

Magnetic ZnFe2O4 hollow fibers were synthesized via a facile bio-template method involving pore-fabricating and nanoparticle assembling process. The as-prepared kapok-morphic ZnFe2O4 exhibited hollow fiber structure composed of nanocrystallites with grain sizes of 30–50nm. The adsorption kinetics equilibrium and thermodynamics of acid fuchsin onto ZnFe2O4 were investigated. It was found that the adsorption was spontaneous and exothermic, and the adsorption process was well described by both the Langmuir isotherm model and the pseudo-second order kinetics model. The maximum adsorption capacity of ZnFe2O4 hollow fibers for acid fuchsin was 150.37mg/g. Electrostatic absorption was conceived as the main adsorption mechanisms.

Mesoporous zinc ferrite: Synthesis, characterization, and photocatalytic activity with H2O2/visible light

Mesoporous ZnFe2O4 (meso-ZnFe2O4) was synthesized by a hydrothermal process in which cetyltrimethylammonium bromide (CTAB) participates in the reaction to produce nanocrystals. Synthesized ZnFe2O4 was characterized by energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET) surface area, scanning electronic microscopy (SEM), transmission electron microscopy (TEM), and diffuse reflectance spectra (DRS). The meso-ZnFe2O4 was resulted from the agglomeration of nanoparticles with size of 5–10nm. The photocatalytic activity of ZnFe2O4 under visible light (λ>400nm) was evaluated by the degradation of Acid Orange II (AOII) at different sintering temperatures, the amount of ZnFe2O4, and the concentration of H2O2. The photocatalytic degradation of AOII was almost complete within 2h in H2O2/visible light system. The high efficiency for AOII degradation was attributed to the strong absorption of ZnFe2O4 in visible-light region and the generation of reactive OH by H2O2 in the system. The involvement of OH in oxidizing AOII was examined by determining the photocurrent of ZnFe2O4, [OH], and degradation rates using different scavengers. Organic compounds as intermediates of the degradation process were identified by LC/MS. Moreover, ZnFe2O4 retained their degradation efficiencies for a series of repetitive batch runs, indicating the true photocatalytic process.