Jie Liu,Youlin Xiong,Ting Wu,Xining Zhang,Jialin Zhao,Shuangfei Cai,Wei Zhang,Rong Yang
Rational design and controllable construction of supported nanostructures with excellent antibacterial property remain a great challenge. Recently, transition metal carbides/nitrides/carbonitrides (MXenes) have attracted much interest in many fields due to their large specific surface areas and good photothermal property. Herein, a simple yet effective surface engineering strategy based on the tuning of MXene surface chemistry is presented, which allows in-situ controlled growth of the Pd nanocubes on the V 2 CT x nanosheets. Briefly, the exfoliated V 2 CT x nanosheets by HF are annealed, which changes the composition of surface terminations while creating the mesoporous structures. The annealing largely affects the exposure and oxidation states of the adjacent V atoms and allows the controllable growth of Pd nanocubes. Interestingly, the obtained Pd@V 2 CT x nanocomposites show enhanced peroxidase-/oxidase-like activities and intrinsic photothermal effect in the near infra-red (NIR) region due to the strong metal-support interaction. Furthermore, the combined nanocatalytic-photothermal treatment by their versatilities remarkably improves the antibacterial efficacy, giving a high killing rate (above 98 % for both Escherichia coli and Staphylococcus aureus ). This work provides a new avenue to develop the supported metal nanostructures based on MXenes for antibacterial application.
Lithium–sulfur batteries (LSBs) currently face challenges including lithium polysulfide shuttling, sluggish sulfur redox kinetics, severe lithium dendrite growth, and volume change. Herein, an advanced dual-functional host is designed by embedding 3D N-doped carbon fibers with abundant 2D V 2 CT x nanosheets (N/CF@V 2 CT x ). The N-doped carbon fibers act as “thread” to connect the V 2 CT x nanosheets and form a unique open 3D macroporous structure. This structure effectively prevents the restacking of the V 2 CT x nanosheets and exposes their lithiophilic and sulfurophilic sites. Consequently, the N/CF@V 2 CT x host effectively suppresses the shuttling of LiPSs and improves the cathodic kinetics. Furthermore, the 3D-ordered porous skeleton integrated with abundant lithophilic sites enables uniform Li deposition and homogeneous Li-ion flux, thereby inhibiting dendrite growth and mitigating volume expansion. The as-assembled LSBs exhibit excellent rate capability (640 mAh g −1 at 15 C) and outstanding cycling stability (0.019% capacity decay per cycle throughout 1200 cycles at 1 C). Moreover, the pouch cell assembled with the N/CF@V 2 CT x host demonstrates a high energy density of 350 Wh kg −1 and good cycling stability. This research presents a promising approach to address the challenges of both the sulfur cathode and the lithium anode comprehensively and effectively in working LSBs.
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