Synthesis of a Carbonaceous Two-Dimensional Material

Mechanical and Lattice Thermal Properties of Si-Ge Lateral Heterostructures

Two-dimensional (2D) materials have drawn extensive attention due to their exceptional characteristics and potential uses in electronics and energy storage. This investigation employs simulations using molecular dynamics to examine the mechanical and thermal transport attributes of the 2D silicene-germanene (Si-Ge) lateral heterostructure. The pre-existing cracks of the Si-Ge lateral heterostructure are addressed with external strain. Then, the effect of vacancy defects and temperature on the mechanical attributes is also investigated. By manipulating temperature and incorporating vacancy defects and pre-fabricated cracks, the mechanical behaviors of the Si-Ge heterostructure can be significantly modulated. In order to investigate the heat transport performance of the Si-Ge lateral heterostructure, a non-equilibrium molecular dynamics approach is employed. The efficient phonon average free path is obtained as 136.09 nm and 194.34 nm, respectively, in the Si-Ge heterostructure with a zigzag and armchair interface. Our results present the design and application of thermal management devices based on the Si-Ge lateral heterostructure.

Template Evolution Induced Relay Self-Assembly for Mesoporous Carbonaceous Materials via Hydrothermal Carbonization

Constructing carbonaceous materials with versatile surface structures still remains a great challenge due to limited self-assembly methods, especially at high temperatures. This study presents an innovative template evolution induced relay self-assembly (TEIRSA) for the fabrication of large polyoxometalate (POM)-mixed carbonaceous nanosheets featuring surface mesoporous structures through hydrothermal carbonization (HTC). The method employs POM and acetone as additives, cleverly modulating the Ostwald ripening-like process of P123-based micelles, effectively addressing the instability challenges inherent in traditional soft-template methods, especially within the demanding carbohydrate HTC process. Additionally, this method allows for the independent regulation of surface architectures through the selection of organic additives. The resulting nanosheets exhibit diverse surface morphologies, including surface spherical mesopores, 1D open channels, and smooth surfaces. Their unexpectedly versatile properties have swiftly garnered recognition, showing potential in the application of lithium-sulfur batteries.

Removal of methanol from water by capacitive deionization system combined with functional nanoporous graphene membrane

In this article, molecular dynamics simulations were used to examine the feasibility of capacitive deionization (CDI) system combined with a functionalized nanoporous graphene (NPG) membrane for removing methanol from water. The radial distribution function of electrode-methanol and methanol-water, the self-diffusion coefficient of methanol and water, the water density near the membrane, the interaction energy between methanol and membrane, the hydrogen bond structure between methanol and water, and the 2D density map of methanol molecules near the membrane under different electric field (EF) (to simulate the effect of capacitance) were examined to evaluate the separation performance of NPG membranes with hydrogen-passivated pores for methanol. The findings show that an EF with appropriate strength can decrease the amount of water molecules near methanol, increase the self-diffusion coefficient of methanol and water, increase hydrophobicity of hydrogenated pores, decrease the interaction between the NPG membrane and methanol, and weaken hydrogen bond interaction between water and methanol molecules. All these findings suggest that an appropriate EF can improve the NPG membrane's permeability to methanol, and verify the feasibility of CDI system combined with hydrogenated NPG membrane to remove methanol from water. This study is expected to propose a potential CDI application technology, and also give a novel idea for the removal of small organic molecules in water by functionalized NPG membrane.

Poly(vinyl alcohol)-Modified Membranes by Ti3C2T x for Ethanol Dehydration via Pervaporation

In this paper, PVA/Ti3C2T x mixed matrix membranes (MMMs) were prepared by mixing the synthesized Ti3C2T x with the PVA matrix, and the pervaporation (PV) performance of the ethanol-water binary system was tested. The morphology, structural properties, and surface characteristics of the membranes were investigated by scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, degree of swelling, and water contact angle. The PVA/Ti3C2T x MMMs exhibit excellent compatibility and swelling resistance. Moreover the effects of the Ti3C2T x filling level, feed concentration, and operating temperature on the ethanol dehydration performance were systematically studied. The results demonstrated that the separation factor of PVA/Ti3C2T x MMMs was significantly increased because of Ti3C2T x promoting the cross-linking density of the membrane. Specifically, the membrane showed the best PV performance when Ti3C2T x loading was 3.0 wt %, achieving a separation factor of 2585 and a suitable total flux of 0.074 kg/m2 h for separating 93 wt % ethanol solution at 37 °C.