Among van der Waals layered ferromagnets, monolayer vanadium diselenide (VSe2) stands out due to its robust ferromagnetism. However, the exfoliation of monolayer VSe2 is challenging, not least because the monolayer flake is extremely unstable in air. Using an electrochemical exfoliation approach with organic cations as the intercalants, monolayer 1T‐VSe2 flakes are successfully obtained from the bulk crystal at high yield. Thiol molecules are further introduced onto the VSe2 surface to passivate the exfoliated flakes, which improves the air stability of the flakes for subsequent characterizations. Room‐temperature ferromagnetism is confirmed on the exfoliated 2D VSe2 flakes using a superconducting quantum interference device (SQUID), X‐ray magnetic circular dichroism (XMCD), and magnetic force microscopy (MFM), where the monolayer flake displays the strongest ferromagnetic properties. Se vacancies, which can be ubiquitous in such materials, also contribute to the ferromagnetism of VSe2, although density functional theory (DFT) calculations show that such effect can be minimized by physisorbed oxygen molecules or covalently bound thiol molecules.

Surface-assisted covalent synthesis currently evolves into an important approach for the fabrication of functional nanostructures at interfaces. Here, we employ scanning tunneling microscopy to investigate the homocoupling reaction of linear, terminal alkyne-functionalized polyphenylene building-blocks on noble metal surfaces under ultrahigh vacuum. On the flat Ag(111) surface, thermal activation triggers a variety of side-reactions resulting in irregularly branched polymeric networks. Upon alignment along the step-edges of the Ag(877) vicinal surface drastically improves the chemoselectivity of the linking process permitting the controlled synthesis of extended-graphdiyne wires with lengths reaching 30 nm. The ideal hydrocarbon scaffold is characterized by density functional theory as a 1D, direct band gap semiconductor material with both HOMO and LUMO-derived bands promisingly isolated within the electronic structure. The templating approach should be applicable to related organic precursors and different reaction schemes thus bears general promise for the engineering of novel low-dimensional carbon-based materials.

Here we reported the antibacterial effect and related mechanism of three nano-Mg(OH)(2) slurries using Escherichia coli as model bacteria. X-ray diffraction (XRD), scanning electron microscopy (SEM) and laser particle size analysis revealed that the as-synthesized Mg(OH)(2)_(MgCl2), Mg(OH)(2)_(MgSO4) and Mg(OH)(2)_(MgO) are all composed by nanoflakes with different sizes, and their aggregates in water are 5.5, 4.5, and 1.2 μm, respectively. Bactericidal tests showed that the antibacterial efficiency is conversely correlated with the size of Mg(OH)(2) aggregates. Transmission electron microscopy (TEM) observation have not provided evidence of cellular internalization, however, the antibacterial effect is positive correlation to the loss of integrity of cell walls. SEM and zeta potential analysis revealed that the adhering ability of Mg(OH)(2) on the bacterial surface is Mg(OH)(2)_(MgCl2) > Mg(OH)(2)_(MgSO4) > Mg(OH)(2)_(MgO), indicating the toxicity of Mg(OH)(2) may be caused by the electrostatic interaction-induced external adsorption. Confocal laser scanning microscopy (CLSM) further revealed that the adhering of Mg(OH)(2) on the bacterial surface could increase the permeability of cell membranes. Taken together, the antibacterial mechanism of nano-Mg(OH)(2) could be as follows: nano-Mg(OH)(2) adsorbed on the bacterial surface by charge attraction first, and then destroyed the integrity of cell walls, which resulting in the final death of bacteria.