Theoretical Investigation of Single-Atom Catalysts for Hydrogen Evolution Reaction Based on Two-Dimensional Tetragonal MoC.

Developing highly efficient and cost-competitive electrocatalysts for the hydrogen evolution reaction (HER), which can be applied to hydrogen production by water splitting, is of great significance in the future of the zero-carbon economy. Here, by means of first-principles calculations, we have scrutinized the HER catalytic capacity of single-atom catalysts (SACs) by embedding transition-metal atoms in the C and Mo vacancies of a tetragonal MoC slab, where the transition-metal atoms refer to Ti, V, Cr, Mn, Fe, Co, Ni and Cu. All the MoC-based SACs exhibit excellent electrical conductivity, which is favorable to charge transfer during HER.

Theoretical Investigation of a Novel Two-Dimensional Non-MXene MoC as a Prospective Anode Material for Li- and Na-Ion Batteries.

A new two-dimensional (2D) non-MXene transition metal carbide, MoC, was found using the USPEX code. Comprehensive first-principles calculations show that the MoC monolayer exhibits thermal, dynamic, and mechanical stability, which can ensure excellent durability in practical applications. The optimized structures of Li@(3×3)-MoC ( = 1-36) and Na@(3×3)-MoC ( = 1-32) were identified as prospective anode materials.

Prediction of allotropes of tellurium with molecular, one- and two-dimensional covalent nets for photofunctional applications.

In the present work, three new semiconducting two-dimensional (2D) Te phases containing three- and four-coordinated Te centers were proposed by using evolutionary algorithms combined with first-principles calculations. Using density functional theory calculations, we discussed the bonding and electronic properties in these phases, and subsequently rationalized their structures. The viability of these predicted structures was demonstrated by evaluating their thermodynamic, dynamic, mechanical, and thermal stabilities.

Emergence of novel hydrogen chlorides under high pressure.

HCl is a textbook example of a polar covalent molecule, and has a wide range of industrial applications. Inspired by the discovery of unexpected stable sodium and potassium chlorides, we performed systematic ab initio evolutionary searches for all stable compounds in the H-Cl system at pressures up to 400 GPa. Besides HCl, four new stoichiometries (HCl, HCl, HCl and HCl) are found to be stable under pressure.

Pressure-driven formation and stabilization of superconductive chromium hydrides.

Chromium hydride is a prototype stoichiometric transition metal hydride. The phase diagram of Cr-H system at high pressures remains largely unexplored due to the challenges in dealing with the high activation barriers and complications in handing hydrogen under pressure. We have performed an extensive structural study on Cr-H system at pressure range 0 ∼ 300 GPa using an unbiased structure prediction method based on evolutionary algorithm.

Phase stability, chemical bonding and mechanical properties of titanium nitrides: a first-principles study.

We have performed first-principles evolutionary searches for stable Ti-N compounds and have found, in addition to the well-known rock-salt TiN, new ground states Ti3N2, Ti4N3, Ti6N5 at atmospheric pressure, and Ti2N and TiN2 at higher pressures. The latter nitrogen-rich structure contains encapsulated N2 dumbbells with a N-N distance of 1.348 Å at 60 GPa.