MOF‑Derived CoSe2@N‑Doped Carbon Matrix Confined in Hollow Mesoporous Carbon Nanospheres as High‑Performance Anodes for Potassium‑Ion Batteries

In this work,a novel vacuum-assisted strategy is proposed to homogenously form Metal-organic frameworks within hollow mesoporous carbon nanospheres(HMCSs)via a solid-state reaction.The method is applied to synthesize an ultrafine CoSe2 nanocrystal@N-doped carbon matrix confined within HMCSs(denoted as CoSe2@NC/HMCS)for use as advanced anodes in highperformance potassium-ion batteries(KIBs).The approach involves a solvent-free thermal treatment to form a Co-based zeolitic imidazolate framework(ZIF-67)within the HMCS templates under vacuum conditions and the subsequent selenization.Thermal treatment under vacuum facilitates the infiltration of the cobalt precursor and organic linker into the HMCS and simultaneously transforms them into stable ZIF-67 particles without any solvents.During the subsequent selenization process,the“dual confinement system”,composed of both the N-doped carbon matrix derived from the organic linker and the small-sized pores of HMCS,can effectively suppress the overgrowth of CoSe2 nanocrystals.Thus,the resulting uniquely structured composite exhibits a stable cycling performance(442 mAh g^−1 at 0.1 A g^−1 after 120 cycles)and excellent rate capability(263 mAh g^−1 at 2.0 A g^−1)as the anode material for KIBs.

Hierarchically nitrogen-doped mesoporous carbon nanospheres with dual ion adsorption capability for superior rate and ultra-stable zinc ion hybrid supercapacitors

Although significant progress has been achieved in developing high energy aqueous zinc ion hybrid supercapacitors(ZHSCs),the sluggish diffusion of zinc ion(Zn^(2+))and unsatisfactory cathodes still hinder their energy density and cycling life span.This work demonstrates the use of nitrogen-doped mesoporous carbon nanospheres(NMCSs)with appropriately hierarchical pore distribution and enhanced zinc ion storage capability for efficient Zn^(2+)storage.The asprepared aqueous ZHSC delivers a significant specific capacity of 157.8 mA h g^(-1),a maximum energy density of 126.2 W h kg^(-1) at 0.2 A g^(-1),and an ultra-high power density of 39.9 kW kg^(-1) with a quick charge time of 5.5 s.Furthermore,the ZHSC demonstrates an ultra-long cycling life span of 50,000 cycles with an exciting capacity retention of 96.2%.More interestingly,a new type of planar ZHSC is fabricated with outstanding low-temperature electrochemical performance,landmark volumetric energy density of 31.6 mW h cm^(-3),and excellent serial and parallel integration.Mechanism investigation verifies that the superior electrochemical capability is due to the synergistic effect of cation and anion adsorption,as well as the reversible chemical adsorption of NMCSs.This work provides not only an innovative strategy to construct and develop novel high-performance ZHSCs,but also a deeper understanding of the electrochemical characteristics of ZHSCs.

A highly accessible copper single-atom catalyst for wound antibacterial application

Bacterial infection arised from multipathogenic bacteria is a tricky issue that attracts worldwide attentions.In this paper,a highly accessible copper single-atom catalyst(Cu SAC)supported by biocompatible N-doped mesoporous carbon nanospheres was synthesized with the emulsion-template method.The tightly anchored copper single-atom of the catalyst could effectively transform O_(2) into O_(2)−•under ambient conditions by the ultra-large pore size(~23.80 nm)and small particle size(~97.71 nm).Due to multiple synergistically oxidative damages to biomolecules,the Cu SAC could be employed to eliminate different bacteria in vitro without the generation of multidrug resistance(MDR).Moreover,the Cu SAC could also promote wound healing in vivo by eradicating the propagation of bacteria at wound.It is envisioned that the Cu SAC with superior antibacterial performance could be applied in the treatment of related bacterial infection in future.