MOF-derived Fe/Ni@C marigold-like nanosheets as heterogeneous electro-Fenton cathode for efficient antibiotic oxytetracycline degradation.

The widespread occurrence of organic antibiotic pollution in the environment and the associated harmful effects necessitate effective treatment method. Heterogeneous electro-Fenton (hetero-EF) has been regarded as one of the most promising techniques towards organic pollutant removal. However, the preparation of efficient cathode still remains challenging. Herein, a novel metal-organic framework (MOF)-derived Fe/Ni@C marigold-like nanosheets were fabricated successfully for the degradation of oxytetracycline (OTC) by serving as the hetero-EF cathode. The FeNi3@C (Fe/Ni molar ratio of 1:3) based hetero-EF system exhibited 8.2 times faster OTC removal rate than that of anodic oxidation and possessed many advantages such as excellent OTC degradation efficiency (95.4% within 90 min), broad environmental adaptability (satisfactory treatment performance for multiple antibiotics under various actual water matrixes), good stability and reusability, and significant toxicity reduction. The superior hetero-EF catalytic performance was mainly attributed to: 1) porous carbon and Ni existence were both conducive to the in-situ generation of H2O2 from dissolved O2; 2) the synergistic effects of bimetals together with electron transfer from the cathode promoted the regeneration of ≡ FeII/NiII, thereby accelerating the production of reactive oxygen species; 3) the unique nanosheet structure derived from the precursor two-dimensional Fe-Ni MOFs enhanced the accessibility of active sites. This work presented a promising hetero-EF cathode for the electrocatalytic treatment of antibiotic-containing wastewaters.

Two Birds with One Stone: FeS2@C Yolk-Shell Composite for High-Performance Sodium-Ion Energy Storage and Electromagnetic Wave Absorption.

Cost-effective material with a rational design is significant for both sodium-ion batteries (SIBs) and electromagnetic wave (EMW) absorption. Herein, we report an elaborate yolk-shell FeS2@C nanocomposite as a promising material for application in both SIBs and EMW absorption. When applied as an anode material in SIBs, the yolk-shell structure not only facilitates a fast electron transport and shortens Na ion diffusion paths but also eases the huge volume change of FeS2 during repeated discharge/charge processes. The as-developed FeS2@C exhibits a high specific capacity of 616 mA h g-1 after 100 cycles at 0.1 A g-1 with excellent rate performance. Furthermore, owing to the significant cavity and interfacial effects enabled by yolk-shell structuring, the FeS2@C nanocomposite delivers excellent EMW absorption properties with a strong reflection loss (-45 dB with 1.45 mm matching thickness) and a broad 15.4 GHz bandwidth. This work inspires the development of high-performance bifunctional materials.