Zhi-Qiang Wang,Biao Zeng,Dan Zhou,Lu Tai,Xiao-Dong Liu,Woon-Ming Lau
Sodium ion battery (SIB) is considered as one of the most promising alternatives to Lithium ion battery (LIB) for large-scale energy storage, but wide usages of SIB are hindered by the lack of suitable anode materials with long cycling lifespan and high-rate capacity. With the merits of high theoretical specific capacity, preferable environmental benignity and wide resources availability, FeSe 2 -based materials have recently emerged as an attractive choice of SIB anode materials. In this work, a novel rich-oxygen-doped FeSe 2 nanosheets (O-FeSe 2 NSs) was constructed as a high-performance anode material for SIB. Substantially, the rich O on O-FeSe 2 NSs effectively promotes the active material and its intermediate reaction products to form an amorphous phase during cycling and hence alleviates the electrode’s volume expansion which usually causes poor cycling stability. Besides, the rich O atoms enables the formation of stable Solid electrolyte interface (SEI) as well as fast diffusion rate of Na + , and therefore enhances the cycling life of the electrode. In addition, the unique sheet structure with rich O atoms endows O-FeSe 2 NSs with super-high pseudocapacitance capacity which facilitates high-rate capabilities. Consequently, the O-FeSe 2 NSs electrode displays prolonged cycling life and high-rate capacity with a large specific capacity of 268.4/268.6 mAh g −1 which is kept even after 700 cycles under the current density of 1.0 A g −1 . Combined with detailed survey of electrochemical storage mechanism and Na + diffusion kinetics, the present work is expected to provide a new research idea of FeSe 2 -based anode materials and motivates a deep understanding of the Na-storage in the O-FeSe 2 NSs host for rechargeable SIB.
Lan Fang,Jie Wang,Xueliang Ouyang,Binbin Liang,Liying Zhao,Dechun Huang,Dawei Deng
Multi-functionality has been a constant pursuit in the development of next-generation drug carriers, as it will bring the potential for combination therapy by integrating diverse therapeutic modes. In this work, FeSe2 nanosheets (NSs) have been prepared as a bifunctional platform to investigate their use in synergistic cancer therapy. Bifunctional FeSe2 NSs exhibit exceptional Fenton-like activity that generates cytotoxic hydroxyl radical (˙OH) and strong broad photothermal performance including the second-infrared (NIR-II) spectral range, wherein the ˙OH production can be enhanced by NIR-II light irradiation. Furthermore, doxorubicin (DOX) was conjugated onto NSs via a pH-responsive hydrazone bond to achieve preferential drug release in an acidic microenvironment. Upon intratumoral administration, these bifunctional drug-carrying FeSe2 NSs showed an NIR-II irradiation-reinforced strong tumor suppression effect, and no obvious toxicity to normal tissues was observed. This study provides a new paradigm for the design of advanced drug carriers relying on their inherent physicochemical properties.
Jia Jia,Qiqi Zhang,Zong Li,Xiaoyun Hu,Enzhou Liu,Jun Fan
Two-dimensional (2D) layered heterostructures have attracted substantial attention in recent years as promising platforms for the direct conversion of renewable solar energy to chemical fuels due to their unique optoelectronic, transport, and interfacial properties. The rational structural design and tailored synthesis of semiconductor heterojunctions are critical to explore and achieve well-defined photocatalytic systems. Herein, we propose a design strategy for ultrathin 2D FeS–FeSe2 lateral heterostructures to achieve rapid spatial migration of photogenerated charge carriers and to facilitate favorable kinetics of target surface redox reactions for photocatalysis. The resultant composites have superior photocatalytic H2 generation activity (2071.1 μmol g−1 h−1) without any noble metal as a cocatalyst under sunlight and show marked photocatalytic durability after a continuous test for 20 h under alkaline conditions. In particular, we have found, for the first time, that the irradiated FeS–FeSe2 is active for producing H2O2 by the two-electron reduction of O2 in the photocatalytic degradation process of phenol solution. A series of mechanistic studies on photocatalysis clearly demonstrates that the pronounced photocatalytic performance of the 2D lateral heterojunction nanosheets could be a result of increased carrier density, longer electron lifetime and higher hole injection efficiency as well as a stepwise two-electron/two-step reduction pathway.
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