Facile synthesis of Ni based metal-organic frameworks wrapped MnO2 nanowires with high performance toward electrochemical oxygen evolution reaction

Nonspherical Metal-Based Nanoarchitectures: Synthesis and Impact of Size, Shape, and Composition on Their Biological Activity

Metal-based nanoentities, apart from being indispensable research tools, have found extensive use in the industrial and biomedical arena. Because their biological impacts are governed by factors such as size, shape, and composition, such issues must be taken into account when these materials are incorporated into multi-component ensembles for clinical applications. The size and shape (rods, wires, sheets, tubes, and cages) of metallic nanostructures influence cell viability by virtue of their varied geometry and physicochemical interactions with mammalian cell membranes. The anisotropic properties of nonspherical metal-based nanoarchitectures render them exciting candidates for biomedical applications. Here, the size-, shape-, and composition-dependent properties of nonspherical metal-based nanoarchitectures are reviewed in the context of their potential applications in cancer diagnostics and therapeutics, as well as, in regenerative medicine. Strategies for the synthesis of nonspherical metal-based nanoarchitectures and their cytotoxicity and immunological profiles are also comprehensively appraised.

Organic Small Molecule Activates Transition Metal Foam for Efficient Oxygen Evolution Reaction

Developing low-cost, highly efficient, and durable electrocatalysts for oxygen evolution reaction (OER) is essential for the practical application of electrochemical water splitting. Herein, it is discovered that organic small molecule (hexabromobenzene, HBB) can activate commercial transition metal (Ni, Fe, and NiFe) foam by directly evolving metal nanomeshes embedded in graphene-like films (M-NM@G) through a facile Br-induced solid-phase migration process. Systematic investigations indicate that HBB can conformally generate graphene-like network on bulk metal foam substrate via the cleavage of CBr bonds and the formation of CC linkage. Simultaneously, the cleaved CBr fragments can efficiently extract metal atoms from bulk substrate, in situ producing transition metal nanomeshes embedded in the graphene-like films. As a result, such functional nanostructure can serve as an efficient OER electrocatalyst with a low overpotential and excellent long-term stability. Specifically, the overpotential at 100 mA cm^-2 is only 208 mV for NiFe-NM@G, ranking the top-tier OER electrocatalysts. This work demonstrates an intriguing general strategy for directly transforming bulk transition metals into nanostructured functional electrocatalysts via the interaction with organic small molecules, opening up opportunities for bridging the application of organic small molecules in energy technologies.

Electrochemically grown MnO2 nanowires for supercapacitor and electrocatalysis applications

In this study, MnO₂ nanowires are electrochemically grown over a 3D nickel foam (NF) substrate using cyclicvoltammetry at 27 °C; furthermore, their potential for applications in supercapacitors and oxygen evolution reaction (OER) is highlighted.