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The vibrational, electronic, and magnetic properties of two-dimensional ${\mathrm{Cr}}_{2}N$ MXene were investigated. Two crystal cells (hexagonal and monoclinic) were considered with their respective magnetic space groups. In the absence of experimental data to fine-tune the $U_{\mathrm{eff}}$ (Hubbard correction), we utilized cell parameters and magnetic moment as a reference window, derived from meta-GGA calculations performed with the SCAN functional. A value of $U_{\mathrm{eff}}$ (1.25 eV) was determined, which does not overestimate the lattice parameters and magnetic moment values. Phonon scattering was calculated, and the vibrational modes were indexed. According to the density of states, the observed splitting in the $e_g$ and $t_{2g}$ orbitals, and the crystal field analysis, we deduce that chromium in the MXene ${\mathrm{Cr}}_{2}N$ predominantly adopts an octahedral coordination environment, a combination of octahedral and tetrahedral coordination results in the splitting of the d orbitals. Finally, using Monte Carlo simulation, the critical temperature ($T_c$) for each space group with different functionals was obtained.

A better understanding of the microstructure, physicochemical properties, and sensing behavior of an electrode is critical in developing quick, high sensitivity, and robust electrochemical sensors. In this study, a single electrode was fabricated with self-prepared graphene ink through a drop-cast process followed with a subsequent annealing treatment. The graphene ink-based electrodes were characterized through AFM, contact angle, FTIR, impedance spectra, Raman, and SEM to understand annealing treatment effects. The dynamic response of the electrode to humidity, and vapors of ethanol, propanol, or acetone was measured using a four-point probe station in a closed chamber. The annealing treatment increased the conductivity of the electrode and improved its sensing performance by forming more and sharper protrusions on the electrode surface. These unique surface protrusions suggest that the annealed graphene ink-based electrodes hold great potential in developing high-performance electrochemical sensors.

The interplay between catalytic agents and substrates in composite materials is crucial in the hydrogen evolution reaction (HER). However, maximizing the utilization of support carrier architectures and ensuring the uniform nucleation and growth of active nanocrystals are imperative for the enhancement of HER capabilities in composite nanomaterials. Herein, we demonstrate a homogeneous synthesis of oxygen-modified 2H-phase molybdenum diselenide nanocrystals on titanium carbide (denoted as MoSe₂/O@Ti₃C₂T_x) to achieve an enhanced HER performance. The improved performance is ascribed to the organ-like structure of Ti₃C₂T_x, which offers numerous sites for anchoring MoSe₂ nanocrystals, hence preventing their excessive aggregation and achieve uniform growth. Ultrathin MoSe₂ crystals and Ti₃C₂T_x interact to reduce the energy barrier for water molecule dissociation, thus improving the catalytic performance for HER. The MoSe₂/O@Ti₃C₂T_x catalyst exhibits outstanding HER performance under acidic conditions, achieving a Tafel slope of 82 mV dec^-1 and a low overpotential of 121 mV at a current density of 10 mA cm⁻², comparable to the best reported MoSe₂-based nanocomposite catalysts. Durability assessments indicate sustained performance for a minimum duration of 10 h at a current density of 10 mA cm⁻². This work lays the groundwork for the development of next-generation high-performance nanocomposite hydrogen evolution catalysts.

Dissolved gas analysis (DGA) in transformer oil is an effective method to monitor the operating status of transformers. Based on fundamental principles, the adsorption behavior of decomposed gases from transformer oil (CO, CH₄, C₂H₂, C₂H₄, and C₂H₆) on intrinsic and Rh-doped VSe₂ monolayers is examined. The adsorption structure, adsorption energy, charge transfer, density of state, electron density difference, work function, and desorption properties are discussed to evaluate the potential applications of VSe₂ monolayers as scavengers and gas-sensing materials for transformer oil decomposed gases. The results show that Rh dopant can be stably adsorbed on the surface of VSe₂ monolayer, and the minimum binding energy is −4.957 eV. The adsorption behavior of oil-dissolved gases on the intrinsic VSe₂ monolayer is weak. The sensing performance of VSe₂ monolayer for oil-dissolved gas molecules is significantly enhanced after the introduction of Rh dopant. The sensing performance of Rh-VSe₂ monolayer for CO, C₂H₂, C₂H₄ and C₂H₆ gases is stronger than that of CH₄. Furthermore, in order to improve the applicability of the Rh doped VSe₂ monolayer for the detection of oil-dissolved gases molecules. The effect of electric field on the sensing properties of gas molecules on Rh doped VSe₂ monolayers is also investigated. Finally, the desorption performance of the system is evaluated based on the transition state theory and Van’t-Hoff-Arrhenius expression. The findings of the study not only disclose the method by which the Rh doped VSe₂ monolayer detects the breakdown gasses in transformer oil, but they also offer theoretical recommendations for the advancement of VSe2-based sensors and scavengers.

This study examines the electronic structure and potential energy surfaces of migration paths in various types of bilayer graphene. Using periodic boundary conditions, density functional theory (DFT), and the generalized gradient approximation (GGA) exchange–correlation functional, along with the nudged elastic band (NEB) method, to investigate the structural stability and dynamic equilibrium of twisted bilayer graphenes (TBGs) with twist angles of 13.2° and 21.8°. The results suggest that twist angles significantly impact atomic and electronic properties, including moiré patterns, superlattice periods, and interfragment distances, which in turn influence bilayer graphene strongly correlated electronic quantum states. This research elucidates the fundamental mechanisms of superlubricity and mutual migration pathways of graphene fragments in TBGs. The low migration barriers observed could facilitate transitions between different energy-related phases, which are determined by the lattice moiré patterns and the localization character of the electronic states, resulting in superlubricity. External mechanical factors may affect the quantum properties of TBGs, indicating potential applications in quantum computing and quantum sensing.

The uneven surface of planar zinc (Zn) metal anodes fundamentally reduces the electrochemical reversibility of aqueous Zn metal batteries due to dendritic growth. Herein, an interphase protection layer engineering is formed on the surface of the Zn metal anode through a solution-processed coating method. This interesting carbon layer, composed of carbon nanoparticles obtained from outer flame-derived candle soot (OFCS), exhibits excellent Zn ion capturing and storage capabilities, effectively reducing the accumulation of charge density on the Zn metal surface, providing a homogeneous Zn ion flux and inducing even Zn metal deposition. The OFCS@Zn can promote the desolvation of [Zn(H₂O)₆]²⁺ through strong interaction with Zn ions, mitigating corrosion and hydrogen evolution reactions. The multifunctional integration of the OFCS layer synergistically induces uniform Zn metal plating and inhibits side reactions. Consequently, in the OFCS @Zn | OFCS @Zn symmetric-cell tests, high-rate performance and deep charge/discharge capabilities are demonstrated. The OFCS@Zn anode-based pouch cell exhibits a high discharge capacity of 156.2 mAh g^-1 and maintains a significant capacity retention rate of 95.4 % for 200 cycles at the current density of 1 A g^-1, indicating its potential for enhanced battery stability and efficiency.

Miniaturized and stabilized polarization-sensitive mid-Infrared photodetectors at room temperature are indispensable in fields ranging from medical diagnostics to military surveillance in the next-generation on-chip polarimeters. Emerging two-dimensional materials offer a promising avenue to fulfill these requirements, facilitated by their ease of integration onto complex structures, inherent in-plane anisotropic crystal structures that enhance polarization sensitivity, and robust quantum confinement effects that enable superior photodetection performance at room temperature. Here, we report the systematic investigation of polarization-dependent infrared photoresponse based on Ta₂NiSe₅, revealing significant anisotropy photocurrent with excellent stability at room temperature. Significantly, a large anisotropic ratio of Ta₂NiSe₅ ensures the polarization sensitivity achieves a ratio of 1.23 at 1550 nm. Moreover, at 4.6 μm, the device exhibits a peak photocurrent response of 1.16 A/W along the armchair orientation, with an anisotropy ratio of approximately 3.3. These findings not only enhance our understanding of the photophysical mechanisms in two-dimensional materials but also guide the optimization of photodetector design for enhanced performance.

As key components of next-generation battery energy storage systems, solid-state batteries have attracted widespread attention. Li₁₀GeP₂S₁₂ (LGPS)-type solid-state electrolytes (SSEs) are favored by researchers owing to their excellent ionic conductivity and potential high-temperature stability. However, the poor interface between LGPS-type SSEs and electrodes has seriously hindered the commercialization of LGPS all-solid-state lithium batteries. This review introduces the structure and Li-ion conduction mechanisms of LGPS-type SSEs and discusses the challenges related to LGPS-type SSEs/electrode interfaces, along with strategies for overcoming these challenges. To improve the interface compatibility, researchers have developed feasible methods for improving and optimizing LGPS-type SSEs. The review concludes with potential research directions and prospects of future LGPS all-solid-state lithium batteries.

Penta-octa-graphene (POG) consists of pentagonal and octagonal carbon rings, hosting type-I and type-II Dirac line nodes due to its sp² and sp³ mixed bonds. Inorganic analogs of 2D carbon lattices have increased the potential applications and changed the main properties of carbon-based structures. Therefore, this work proposes penta-octa-graphene based on silicon carbide using DFT simulations. With a cohesive energy of −5.22 eV/atom, POG-Si₅C₄ is energetically viable in comparison with other silicon carbide-based monolayers. Phonon dispersion analysis confirms the POG-Si₅C₄ dynamical stability. MD simulations demonstrate that this new monolayer can withstand temperatures up to 1020 K. Electronic analysis indicates it is a semiconductor with an indirect band gap transition of 2.02 eV. The mechanical properties exhibit anisotropy, with Young’s modulus ranging from 38.65 to 99.47 N/m and an unusual negative Poisson’s ratio of −0.09. The band edge alignment suggests that POG-Si₅C₄ holds potential for hydrogen generation through photocatalytic water splitting. This research opens possibilities for designing inorganic penta-octa-based structures and provides insights for future experimental and theoretical studies focused on exploring and optimizing advanced silicon-carbide 2D materials.

MXene’s outstanding performance in driving the Hydrogen Evolution Reaction (HER) has attracted significant interest. The HER involves hydrogen generation by electrolyzing water. It is widely recognized that hydrogen represents a renewable and future-oriented alternative energy source that is currently receiving significant attention. On the other hand, MXenes also have a crucial function as catalysts, elevating the pace and effectiveness of chemical reactions. Moreover, their properties make them essential in diverse fields, contributing to advancements in energy storage, sensing technology, and catalysis for improved reactions. Herein, we highlighted MXene nanocomposite materials from synthesized to utilization in HER reaction both experimentally and theoretically. Various MXene-based nanocomposites, which consist of monomer, carbon, and oxide that can be used in hydrogen evolution reactions, are also elaborated in detail. Ultimately, we concluded this review with the future prospect of MXenes in electrochemical HER.