Ionic liquid-assisted synthesis of N, F, and B co-doped BiOBr/Bi2Se3 on Mo2CTx for enhanced performance in hydrogen evolution reaction and supercapacitors.

Heteroatom doping and heterojunction formation are effective strategies to enhance electrochemical performance. In this study, we present a novel approach that utilizes an ionic liquid-assisted synthesis method to fabricate a BiOBr-based material, which is subsequently loaded onto Mo2CTx via a selenization treatment to create a BiOBr/Bi2Se3 heterostructure, denoted as NBF-BiOBr/Bi2Se3/Mo2CTx. The incorporation of heteroatoms improves its hydrophilicity and electronegativity, while the formation of heterojunctions adjusts the electronic structure at the interface, resulting in lower OH-/H+ adsorption energy. The specific surface area of NBF-BiOBr/Bi2Se3/Mo2CTx is 193.1 m2/g. In hydrogen evolution reaction (HER) tests, NBF-BiOBr/Bi2Se3/Mo2CTx exhibits exceptional catalytic performance in acidic media, requiring only an overpotential of 109 mV to achieve a current density of 10 mA cm-2. Furthermore, NBF-BiOBr/Bi2Se3/Mo2CTx demonstrates superior electrochemical performance in an asymmetric supercapacitor, with an energy density as high as 55.6 Wh kg-1 at a power density of 749.9 Wh kg-1. This work provides a novel approach for heteroatom doping and heterojunction synthesis, offering promising prospects for further advancements in the field.

Ionic Liquid Meets MOF: A Facile Method to Optimize the Structure of CoSe2-NiSe2 Heterojunctions with N, P, and F Triple-Doped Carbon Using Ionic Liquid for Efficient Hydrogen Evolution and Flexible Supercapacitors.

The rational design of catalysts' spatial structure is vitally important to boost catalytic performance by exposing the active sites and increasing specific surface area. Herein, the heteroatom doping and morphology of CoNi metal-organic frameworks(MOF) are modulated by controlling the volume of ionic liquid used in synthesis and generating CoSe2 -NiSe2 heterojunction structures wrapped by N, P, F tri-doped carbon(NPFC) after a selenisation process. Notably, the unique cubic porous structure of CoSe2 -NiSe2 /NPFC results in a specific surface five times that of the sheet-like hollow structure produced without ionic liquid. Moreover, the charge redistribution during heterojunction formation is verified in detail using synchrotron radiation. Density functional theory calculations reveal that the formation of heterojunctions and doping of heteroatoms successfully lower the ΔGH* and ΔGOH* values. Consequently, CoSe2 -NiSe2 /NPFC exhibits excellent activity for HER in both acidic and alkaline solutions. Meanwhile, CoSe2 -NiSe2 /NPFC as a cathode material exhibits excellent performance in a flexible solid-state supercapacitor, with a superior energy density of 55.7 Wh kg-1 at an extremely high-power density of 15.9 kW kg-1 . This material design provides new ideas for not only using ionic liquids to modulate the morphology of MOFs but also deriving heterojunctions and heteroatom-doped carbon from MOFs.

Trimodal hierarchical porous carbon nanorods enable high-performance Na-Se batteries.

Technical bottlenecks of polyselenide shuttling and material volume variation significantly hamper the development of emerging sodium-selenium (Na-Se) batteries. The nanopore structure of substrate materials is demonstrated to play a vital role in stabilizing Se cathodes and approaching superior Na-ion storage properties. Herein, an ideal nanorod-like trimodal hierarchical porous carbon (THPC) host is fabricated through a facile one-step carbonization method for advanced Na-Se batteries. The THPC possesses a trimodal nanopore structure encompassing micropores, mesopores, and macropores, and functions as a good accommodator of Se molecules, a reservoir of polyselenide intermediates, a buffer for volume expansion of Se species during sodiation, and a promoter for electron/ion transfer in the electrochemical process. As a result, Na-Se batteries assembled with the Se-THPC composite cathode realize high utilization of Se, fast redox kinetics, and excellent cyclability. Furthermore, the Na-ion storage mechanism of the well-designed Se-THPC composite is profoundly revealed by in situ visual characterization techniques.

A Nanozyme-Immobilized Hydrogel with Endogenous ROS-Scavenging and Oxygen Generation Abilities for Significantly Promoting Oxidative Diabetic Wound Healing.

Non-healing wound is a common complication of diabetic patients associated with high morbidity and mortality. Engineered therapeutic hydrogels have enviable advantages in tissue regeneration, however, they are suboptimal for the healing of diabetic wounds characterized by reactive oxygen species (ROS) accumulation and chronic hypoxia. Here, a unique biological metabolism-inspired hydrogel, for ameliorating this hostile diabetic microenvironment, is presented. Consisting of natural polymers (hydrazide modified hyaluronic acid and aldehyde modified hyaluronic acid) and a metal-organic frameworks derived catalase-mimic nanozyme (ε-polylysine coated mesoporous manganese cobalt oxide), the engineered nanozyme-reinforced hydrogels can not only capture the endogenous elevated ROS in diabetic wounds, but also synergistically produce oxygen through the ROS-driven oxygen production ability. These fascinating properties of hydrogels protect skin cells (e.g., keratinocytes, fibroblasts, and vascular endothelial cells) from ROS and hypoxia-mediated death and proliferation inhibition. Diabetic wounds treated with the nanozyme-reinforced hydrogels highlight the potential of inducing the macrophages polarization from pro-inflammatory phenotype (M1) to anti-inflammatory subtype (M2). The hydrogel dressings demonstrate a prominently accelerated healing rate as shown by alleviating the excessive inflammatory, inducing efficiently proliferation, re-epithelialization, collagen deposition, and neovascularization. This work provides an effective strategy based on nanozyme-reinforced hydrogel as a ROS-driven oxygenerator for enhancing diabetic wound healing.

MOF-Derived Hybrid Hollow Submicrospheres of Nitrogen-Doped Carbon-Encapsulated Bimetallic Ni-Co-S Nanoparticles for Supercapacitors and Lithium Ion Batteries.

The development of bimetallic transition-metal sulfide and nitrogen-doped carbon composites with unique hollow structure is highly desirable for energy storage applications but is also challenging. In the present work, we demonstrate a facile metal-organic framework engaged strategy for synthesizing bimetallic nickel cobalt sulfide and nitrogen-doped carbon composites with hollow spherical structure (denoted as hollow Ni-Co-S- n/NC composites) and a Ni/Co molar ratio ( n value) that can be easily controlled. When evaluated as electrode materials for both supercapacitors and lithium ion batteries, it is found that the hollow Ni-Co-S-0.5/NC composite with a Ni/Co molar ratio of 0.5 exhibits optimal electrochemical performance. The hollow Ni-Co-S-0.5/NC composite exhibits a high specific capacity of 543.9 C g-1 at 1 A g-1 and maintains a capacity retention of 67.3% when the current density is increased to 20 A g-1. An asymmetric supercapacitor based on the hollow Ni-Co-S-0.5/NC composite is fabricated, which shows good electrochemical performance with a high energy density of 39.6 W h kg-1 at a power density of 808 W kg-1. For lithium storage, the hollow Ni-Co-S-0.5/NC composite manifests a high reversible discharge capacity of 755.0 mA h g-1 at 200 mA g-1 for 200 cycles as well as good rate capability. The excellent electrochemical performance could be attributed to the desirable structural, compositional, and component advantages. This work could offer new insight into the rational design and synthesis of highly efficient electrode materials for both supercapacitors and lithium ion batteries.