Optimizing Porous Metal-Organic Layers for Stable Zinc Anodes.

Aqueous zinc-ion batteries (ZIBs) have been considered as alternative stationary energy storage systems, but the dendrite and corrosion issues of Zn anodes hinder their practical applications. Here we report a series of two-dimensional (2D) metal-organic frameworks (MOFs) with Zr12 clusters, which act as artificial solid electrolyte interphase (SEI) layers to prevent dendrites and corrosion of Zn anodes. The Zr12-based 2D MOF layers were formed by incubating 3D layer-pillared Zr-MOFs in ZnSO4 aqueous electrolytes, which replaced the pillar ligands with terminal SO42-. Furthermore, the pore sizes of Zr12-based 2D MOF layers were systematically tuned, leading to optimized Zn2+ conduction properties and protective performance for Zn anodes. In contrast to the traditional 2D-MOFs with Zr6 clusters, Zr12-based 2D MOF layers as artificial SEI significantly reduced the polarization and increased the stability of Zn anodes in MOF@Zn||MOF@Zn symmetric cells and MOF@Zn||MnO2 full cells. In situ experiments and DFT computations reveal that the enhanced cell performance is attributed to the unique Zr12-based layered structure with intrinsic pores to allow fast Zn2+ diffusion, surface Zr-SO4 zincophilic sites to induce uniform Zn deposition, and inhibited hydrogen evolution by 2D MOF Zr12 layers.

A ZIF-8 Host for Dendrite-Free Zinc Anodes and N,O Dual-doped Carbon Cathodes for High-Performance Zinc-Ion Hybrid Capacitors.

Zn is a promising anode for aqueous energy storage owing to it intrinsic superior properties such as large capacity, abundant reserves, low potential and safety. But, the growth of dendrites during charge and discharge leads to a decrease in reversibility. In addition, further development of zinc-ion hybrid capacitors (ZICs) is seriously challenging because of the lack of an exceptional cathode. Herein, we use ZIF-8 annealed at 500 °C (annealed ZIF-8) as a host material for stable and dendrite-free Zn anodes. Utilization of annealed ZIF-8 results in dendrite-free Zn deposition and stripping as a result of its porous construction, which contains trace Zn. Furthermore, we firstly proposed innovative N,O dual-doped carbon which was designed by the derived ZIF-8 (ZIF-8 derived C) as cathode for high-energy and power-density ZICs. The new ZIC assembled by Zn@annealed ZIF-8 anode and ZIF-8 derived C cathode provides a capacity of 135.5 mAh g-1 and an energy density of 108.4 Wh kg-1 with a power density of 800 W kg-1 at 1.0 A g-1 . In addition, it shows outstanding cycling stability of 91% capacity retention after 6000 cycles at 5.0 A g-1 . Moreover, the solid-state ZICs can drive LEDs and smart watches. This ZIC holds promise for the practical application of supercapacitors.

Tumor Microenvironment-Activatable Cyclic Cascade Reaction to Reinforce Multimodal Combination Therapy by Destroying the Extracellular Matrix.

The optimal therapy effect of tumors is frequently restricted by the dense extracellular matrix (ECM) and anoxia. Herein, an intelligent BPNs-Arg-GOx@MnO2 (BAGM) nanozyme is innovatively designed as a multimodal synergistic therapeutic paradigm that possesses both nitric oxide (NO) self-supplying and ECM degradation properties to reinforce the therapy effect by a tumor microenvironment (TME)-activatable cyclic cascade catalytic reaction. This theranostic nanoplatform is constructed by using polyethyleneimine-modified black phosphorus nanosheets as a "fishnet" to attach l-Arginine (l-Arg) and glucose oxidase (GOx) and then depositing mini-sized MnO2 nanosheets (MNs) on the surface by a facile situ biomineralization method. As an intelligent "switch", the MNs can effectively trigger the cascade reaction by disintegrating intracellular H2O2 to release O2. Then, the conjugated GOx can utilize O2 production to catalyze intracellular glucose to generate H2O2, which not only starves the tumor cells but also promotes oxidation of l-Arg to NO. Thereafter, matrix metalloproteinases will be activated by NO production to degrade the dense ECM and transform matrix collagen into a loose state. In turn, a loose ECM can enhance the accumulation of the BAGM nanozyme and thereby reinforce synergistic photothermal therapy/starvation therapy/NO gas therapy. Both in vitro and in vivo results indicate that the TME-tunable BAGM therapeutic nanoplatform with cascade anticancer property and satisfactory biosecurity shows potential in nanomedicine.

Novel magnetically separable anhydride-functionalized Fe3O4@SiO2@PEI-NTDA nanoparticles as effective adsorbents: synthesis, stability and recyclable adsorption performance for heavy metal ions.

In this paper, a novel adsorbent, Fe3O4@SiO2@PEI-NTDA, was first prepared by the immobilization of an amine and anhydride onto magnetic Fe3O4@SiO2 nanoparticles with polyethylenimine (PEI) and 1,4,5,8-naphthalenetetracarboxylic-dianhydride (NTDA) for the removal of heavy metal ions from aqueous solutions. The structure of Fe3O4@SiO2@PEI-NTDA was systematically investigated; the results confirmed that amine and anhydride groups were successfully covalently grafted onto the surface of Fe3O4@SiO2, which showed a homogenous core-shell structure with three layers of about 300 nm diameter (Fe3O4 core: 200 nm, nSiO2 layer: 20 nm, and PEI-NTDA layer: 20 nm). The adsorption performance of Fe3O4@SiO2@PEI-NTDA NPs was evaluated for single Pb2+ and coexisting Cd2+, Ni2+, Cu2+, and Zn2+ ions in an aqueous solution in a batch system. The amine and anhydride groups may have a synergistic effect on Pb2+ removal through electrostatic interactions and chelation; Fe3O4@SiO2@PEI-NTDA NPs exhibited preferable removal of Pb2+ with maximum adsorption capacity of 285.3 mg g-1 for Pb2+ at a solution pH of 6.0, adsorbent dosage of 0.5 g L-1, initial Pb2+ concentration of 200 mg L-1 and contact time of 3 h. The adsorption mechanism conformed well to the Langmuir isotherm model, and the adsorption kinetic data were found to fit the pseudo-second order model. Fe3O4@SiO2@PEI-NTDA NPs could be recovered easily from their dispersion by an external magnetic field and demonstrated good recyclability and reusability for at least 6 cycles with a high adsorption capacity above 204.5 mg g-1. The magnetic adsorbents showed high stability with a weight loss below 0.65% in the acid leaching treatment by 2 M HCl solution for 144 h. This study indicates that Fe3O4@SiO2@PEI-NTDA NPs are new promising adsorbents for the effective removal of Pb2+ in wastewater treatment.