We have performed a theoretical study of the Li/Li 6 PS 5 Cl interface and showed the ability of the applied computational methods to properly describe the chemical processes that occur at the interface. After a 500 ps ab initio molecular dynamics simulation, we find that the Li/Li 6 PS 5 Cl interface decomposes with formation of multiple phases and that the main decomposition products are Li 2 S, Li 3 P, LiCl, and possibly LiP. These findings are in good agreement with reported experimental data. The observed quick decomposition is attributed to the weak bonding between P and S. On the basis of this and earlier obtained experimental results, we conclude that the chemical instability may be an intrinsic problem of P− S-based solid electrolytes when they are in contact with Li-metal. Our results validate the effectiveness of the available computational tools to reach a deeper insight into the evolution of interfacial structures and properties prior to experiment.

Inorganic semiconductor α-Ag2S exhibits a metal-like ductile behavior at room temperature, but the origin of this high ductility has not been fully explored yet. Based on density function theory simulations on the intrinsic mechanical properties of α-Ag2S, its underlying ductile mechanism is attributed to the following three factors: (i) the low ideal shear strength and multiple slip pathways under pressure, (ii) easy movement of Ag–S octagon framework without breaking Ag−S bonds, and (iii) a metallic Ag−Ag bond forms which suppresses the Ag–S frameworks from slipping and holds them together. The easy slip pathways (or easy rearrangement of atoms without breaking bonds) in α-Ag2S provide insight into the understanding of the plastic deformation mechanism of ductile semiconductor materials, which is beneficial for devising and developing flexible semiconductor materials and electronic devices.

The sluggish oxygen reduction reaction (ORR) is a major impediment to the economic use of hydrogen fuel cells in transportation. In this work, we report the full ORR reaction mechanism for Pt(111) based on Quantum Mechanics (QM) based Reactive metadynamics (RμD) simulations including explicit water to obtain free energy reaction barriers at 298 K. The lowest energy pathway for 4 e water formation is: first, *OOH formation; second, *OOH reduction to HO and O*; third, O* hydrolysis using surface water to produce two *OH and finally *OH hydration to water. Water formation is the rate-determining step (RDS) for potentials above 0.87 Volt, the normal operating range. Considering the Eley-Rideal (ER) mechanism involving protons from the solvent, we predict the free energy reaction barrier at 298 K for water formation to be 0.25 eV for an external potential below U = 0.87 V and 0.41 eV at U = 1.23 V, in good agreement with experimental values of 0.22 eV and 0.44 eV, respectively. With the mechanism now fully understood, we can use this now validated methodology to examine the changes upon alloying and surface modifications to increase the rate by reducing the barrier for water formation.

Recently, CO2 reduction to fuels has been the subject of great much numerous studies, but selectivity and activity remain inadequate. Progress has been made on single site twodimensional catalysts based on graphene coupled to a metal and nitrogen for CO2RR but the product is usually CO and the metal-N environment remains ambiguous. We report a novel 2D graphene-nitrene heterostructure (grafiN6) providing well-defined active sites (N6) that can bind 1 to 3 metals for CO2RR. We find that homo-bimetallic FeFe-grafiN6 could reduce CO2 to CH4 at -0.61 V and to CH3CH2OH at -0.68 V vs RHE, with high product selectivity. Moreover, the heteronuclear FeCu-grafiN6 system may be significantly less affected by HER, while maintaining low limiting potential (-0.68 V) for C1 and C2 mechanisms. Binding metals to one N6 site but not the other could promote efficient electron transport facilitating some reaction steps. This framework for single multiple metal sites might also provide unique catalytic sites for other catalytic process.