Excitons, optical spectra, and electronic properties of semiconducting Hf-based MXenes.

Semiconducting MXenes are an intriguing two-dimensional (2D) material class with promising electronic and optoelectronic properties. Here, we focused on recently prepared Hf-based MXenes, namely, Hf3C2O2 and Hf2CO2. Using the first-principles calculation and excited state corrections, we proved their dynamical stability, reconciled their semiconducting behavior, and obtained fundamental gaps by using the many-body GW method (indirect 1.

The electronic and optical properties of III-V binary 2D semiconductors: how to achieve high precision from accurate many-body methods.

Seven hexagonal 2D materials consisting of elements of the IIIA and VA groups (BN, BP, BAs, AlN, GaN, GaP, and GaAs) were theoretically studied using first-principles methods. Simultaneous convergence in all principal parameters of the accurate many-body perturbational GW approach and the subsequent Bethe-Salpeter equation (BSE) was necessary to achieve precise fundamental and optical gaps, exciton binding energies, and absorbance spectra. Various convergence rates of studied properties in the case of different materials were visualized and explained.

Iron Nitride Nanoparticles for Enhanced Reductive Dechlorination of Trichloroethylene.

Nitriding has been used for decades to improve the corrosion resistance of iron and steel materials. Moreover, iron nitrides (FeN) have been shown to give an outstanding catalytic performance in a wide range of applications. We demonstrate that nitriding also substantially enhances the reactivity of zerovalent iron nanoparticles (nZVI) used for groundwater remediation, alongside reducing particle corrosion.

A theoretical study of adsorption on iron sulfides towards nanoparticle modeling.

Surface modification of zero-valent iron (nZVI) nanoparticles, which are frequently used in the removal of chlorinated hydrocarbons from contaminated groundwater, can increase their surface stability without significant loss of reactivity. Sulfidation is a process during which thin iron sulfide phases are formed on nZVI particles. In this work, the adsorption capability of two iron sulfide minerals (mackinawite and pyrite) and ZVI with respect to two small polar molecules (H2O and H2S) and trichloroethylene (TCE) was modeled by using the quantum mechanics (QM) approach.

Accurate many-body calculation of electronic and optical band gap of bulk hexagonal boron nitride.

Many-body perturbational GW approximation in conjunction with the Bethe-Salpeter equation (BSE) has been employed to calculate accurate electronic and optical band gaps of bulk hexagonal boron nitride (h-BN) in the two most important stacking configurations, AA' and AB. The carefully converged results revealed h-BN as an indirect material (indirect gap ≈ 6.1 eV) with a huge excitonic effect (≈0.