MIL-101(Fe)-derived iron oxide/carbon anode for lithium-ion batteries: derivation process study and performance optimization

Electrostatically fabricated heterostructure of interfacial-polarization-enhanced Fe3O4/C/MXene for ultra-wideband electromagnetic wave absorption

Electromagnetic (EM) pollution can disrupt the functioning of advanced electronic devices, hence it's necessary to design EM wave absorbers with high-level absorption capabilities. The Ti3C2Tx (MXene) is classified as a potential EM absorbing material; nevertheless, the lack of magnetic loss mechanism leads to its inadequate EM absorbing performance. On this basis, a novel composite design with promising EM absorption properties is hypothesized to be the integration of few-layer MXene and heterogeneous magnetic MOF derivatives (Fe3O4/C) with complementary advantages. Herein, we synthesized two-dimensional (2D) interfacial-polarization-enhanced MXene hybrid (Fe3O4/C/MXene) by electrostatic assembly. It is notable that the interfacial polarization is realized by adding a small amount of magnetic Fe3O4/C. Furthermore, the Fe3O4/C/ MXene demonstrates an astonishing effective absorption bandwidth (EAB) of 10.7 GHz and an excellent EM wave absorption performance (RLmin) of -66.9 dB. Moreover, the radar cross section (RCS) of Fe3O4/C/MXene is lower than -15.1 dB m2 from -90° to 90° with a minimum RCS value of -52.6 dB m2 at 32°. In addition, the significant attenuation of the EM wave is due to the synergistic effect of improved impedance matching, dielectric loss, and magnetic loss. Thus, the magnetized Fe3O4/C/MXene hybrid is expected to emerge as a strong contender for high-performance EM wave absorbers.

Wood-converted porous carbon decorated with MIL-101(Fe) derivatives for promoting photo-Fenton degradation of ciprofloxacin

In response to the escalating concerns over antibiotics in aquatic environments, the photo-Fenton reaction has been spotlighted as a promising approach to address this issue. Herein, a novel heterogeneous photo-Fenton catalyst (Fe3O4/WPC) with magnetic recyclability was synthesized through a facile two-step process that included in situ growth and subsequent carbonization treatment. This catalyst was utilized to expedite the photocatalytic decomposition of ciprofloxacin (CIP) assisted by H2O2. Characterization results indicated the successful anchoring of MIL-101(Fe)-derived spindle-like Fe3O4 particles in the multi-channeled wood-converted porous carbon (WPC) scaffold. The as-synthesized hybrid photocatalysts, boasting a substantial specific surface area of 414.90 m2·g-1 and an excellent photocurrent density of 0.79 μA·cm-2, demonstrated superior photo-Fenton activity, accomplishing approximately 100% degradation of CIP within 120 min of ultraviolet-light exposure. This can be attributed to the existence of a heterojunction between Fe3O4 and WPC substrate that promotes the migration and enhances the efficient separation of photogenerated electron-hole pairs. Meanwhile, the Fe(III)/Fe(II) redox circulation and mesoporous wood carbon in the catalyst synergistically enhance the utilization of H2O and accelerate the formation of •OH radicals, leading to heightened degradation efficiency of CIP. Experiments utilizing chemical trapping techniques have demonstrated that •OH radicals are instrumental in the CIP degradation process. Furthermore, the study on reusability indicated that the efficiency in removing CIP remained at 89.5% even through five successive cycles, indicating the structural stability and excellent recyclability of Fe3O4/WPC. This research presented a novel pathway for designing magnetically reusable MOFs/wood-derived composites as photo-Fenton catalysts for actual wastewater treatment.

Waste toner-derived porous iron oxide pigments with enhanced catalytic degradation property

'Wealth from Waste' is an emerging concept, since it leads an effective waste treatment and waste recyclability. On the other hand, cost effective production iron oxide (IO) nanomaterials is still needed to develop, owing to their wide applications. Herein, we proposed a simple direct calcination method to prepare porous IO (Fe₃O₄ and Fe₂O₃) nanomaterials from waste toner powder. Characterization techniques reveal that a structural change happened from Fe₃O₄ to γ-Fe₂O₃ and γ-Fe₂O₃ to α-Fe₂O₃ at the calcination temperature of 500 °C and 700 °C respectively. Consequently, optical (band gap) and magnetic parameters of IO samples were significantly varied. The pigment characteristics of the IO samples were evaluated using Commission Internationale de l'Eclairage (CIE) analysis. IO900 sample has shown good brown-red coloration (L* = 43.11, a* = 13.26 and b* = 5.69) and it also exhibited good stability in acidic and basic conditions. Practical applicability of IO pigments were also tested by mixing with plaster of paris (PP) powder. Further, porous IO samples were also used as catalysts in the reductive degradation of methyl orange (MO) dye in presence of excess sodium borohydride (NaBH₄). IO, prepared at 900 °C exhibited ∼99.9% reduction efficiency within 40 min. Recycling experiments indicated that IO900 possess good stability up to seven cycles. The present porous IO samples will become potential in pigment and environmental remediation.