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Layered 2D materials such as transition metal chalcogenides are promising electrocatalysts for hydrogen evolution reaction (HER) due to the flexible compositions and distinctive electronic structures. However, their active sites usually stem from the edges, whereas the basal planes with the higher surface area are difficult to activate for water dissociation and H2 evolution. Here, a novel quasi‐2D AgRuO3 compound, which can be readily activated by cyclic voltammetry and split into layered structures with more exposed basal planes is reported. This results in an outstanding HER activity with a low overpotential of only 37 mV at 10 mA cm−2 and a Tafel slope of 36 mV dec−1. It is found that the oxygen vacancies generated on the basal planes during activation can thermodynamically facilitate water adsorption, dissociation, and intermediate OH* desorption compared with the pristine AgRuO3, as revealed by theoretical calculations. Thus, the oxygen vacancies on the exposed basal planes are the active centers. This work sheds light on the evolution of a quasi‐2D metal oxide during HER and highlights the active role of basal planes that can facilitate water dissociation in alkaline water electrolysis. [ABSTRACT FROM AUTHOR]

Electronic structures of superlattices and encapsulated layers are obtained by Green's function metho d. The simple scheme for estimation of interlayer charge transfer is proposed. As an example, layers of graphene and graphene-like compounds are considered. [ABSTRACT FROM AUTHOR]

This study presents the first investigation of BC 3 semiconductor monolayer using DFT to reveal its electronic, thermal, and optical characteristics. Phonon band structure and ab-initio molecular dynamics simulations provide evidence that BC 3 semiconductor monolayer has the characteristics of a dynamically and thermally stable structure. The electronic band structure of the BC 3 monolayer is studied, revealing a direct band gap and the electron charge distribution indicates dominant covalent bonds in the structure. Analysis of thermal properties, such as entropy, heat capacity, and thermal conductivity, at different temperatures, demonstrated that the BC 3 monolayer displays substantial lattice thermal conductivity. The optical behavior of BC 3 in reaction to infrared light is characterized by notable fluctuations in the refractive index and optical conductivity. The existence of a prominent peak with high intensity in the dielectric function indicates significant absorption in the infrared range, emphasizing the material's potential for applications in optoelectronics and energy harvesting. The results emphasize the promise of the BC 3 semiconductor monolayer as a versatile substance for cutting-edge optoelectronic applications, which will contribute to improvements in infrared technology and other related sectors. [ABSTRACT FROM AUTHOR]

The present study investigates the structural, electronic, thermal, and optical properties of a novel two-dimensional Al 2 Te 3 using GGA and HSE06 functional in the framework of density functional theory. The formation energy, the phonon dispersion, and AIMD calculations confirm the structural, dynamical, and thermal stability of Al 2 Te 3 , respectively. The electronic band structure and partial density of states indicate the semiconducting characteristics of 2D Al 2 Te 3 with band gap values of 1.92 eV (GGA) and 2.78 eV (HSE06). The thermal properties of Al 2 Te 3 reveal a high heat capacity due to a very high phonon density of states. This property signifies the material's growing ability to store thermal energy. Thus the entropy demonstrates a continuous increase with temperature, adhering to the second law of thermodynamics. The analysis of optical properties of Al 2 Te 3 demonstrates strong light interaction in the ultraviolet, UV, region, and the optical band gap is found to be larger than the electronic band gap for both GGA and HSE06 functional due to indirect behavior of the band gap. Furthermore, the static dielectric function, refractive index, and optical conductivity are found to be smaller in the case of HSE06 compared to the GGA which may be due to reduced transition probability, and less screening effects including in the HSE06 functional. These findings offer valuable insights into the potential applications of Al 2 Te 3 in various fields, including thermal energy storage and optoelectronics. • High thermal energy storage of 2D Al2Te3. • AIMD and Phonon dispersion confirm thermal and dynamic stability of Al2Te3. • HSE06 confirm better results comparing to the GGA. • Optical transitions are seen in the ranging from far visible to UV regions. [ABSTRACT FROM AUTHOR]

Based on first-principles methods and Boltzmann transport theory, we investigated the biaxial strain effects on electronic and thermoelectric properties of three group-III nitrides (BN, AlN and GaN) 2D honeycomb mono-layered nanosheets. The direct-indirect band gap transitions occurred for BN and GaN nanosheets when the strain was applied. In addition, the band gaps decreased with increase of tensile strain; and we uncovered the mechanism behind by the total and projected density-of-state (PDOS) analyses. At the same time, we presented the contour plots of their electrical transport properties as a function of both temperature and carrier concentration at strain-free states. Power-factors of BN, AlN and GaN nanosheets were also calculated. We found only peak power factors of p-type GaN and n-type BN showed a strong dependence on biaxial strain. Such differences of the strain-dependent thermoelectric performance among BN, AlN and GaN may be due to the competition between covalency and ionicity in these 2D structures. Our results provide a new avenue to optimize thermoelectric properties of 2D nanosheets by strain engineering. [ABSTRACT FROM AUTHOR]

Based on density functional theory electronic and magnetic structure characterizations an unusual onset of spin polarization of p states is demonstrated leading to a stable ferromagnetic order within a carbon layered honeycomb-like compound. Specifically structural relaxation of formerly studied C 2 N in 3D network and devised here in 2D layered AlB 2 -type derived structure shows that the resulting ordered compound maintains the hexagonal crystal symmetry with an exceptionally large c/a ratio leading to strong localization of N states along c and letting magnetization develop within N-p z orbitals with 1.1 μ B per formula unit. Anisotropic antibonding interactions between C and N layers allow interpreting the results. The compound is energetically characterized in ferromagnetic ground state versus less stable anti-ferromagnetic order. [ABSTRACT FROM AUTHOR]