Initial Oxygen Incorporation in the Prismatic Surfaces of Troilite FeS

Abstract

We present a theoretical investigation of the prismatic (011̅0) surface of troilite in an oxidizing environment, which aims to elucidate the presence of oxygen detected experimentally in the pyrrhotite Fe1–x S nanoparticles. We find that atomic oxygen adsorbs in Fe–O–Fe bridging motifs, which are thermodynamically stable under ambient conditions. During the first oxidation steps, the formation of the S–O bond is less favored than Fe–O, suggesting that the sulfur oxides detected experimentally form only subsequently. We predict, moreover, that substitution of sulfur for oxygen can occur. The appearance of Fe–O–Fe–O–Fe bridging motifs due to successive adsorptions points toward a clustering growth of the oxidic units. In agreement with the experimental observations, the oxidation of troilite is exothermic, where the equilibrium between adsorption and substitution is influenced by the presence of Fe vacancies.

Molecular‐Level Design of Pyrrhotite Electrocatalyst Decorated Hierarchical Porous Carbon Spheres as Nanoreactors for Lithium–Sulfur Batteries

“…[ 58–61 ] To study the LiPs adsorption energies on pyrrhotite (Fe 1− x S), surface models of Fe 7 S 8 , FeS 2 , and Fe 3 S 4 are employed in accordance with previous literatures. [ 62–67 ] For the surface calculations, we study the (001) surfaces, which have previously been shown to be the most stable surface termination for these materials. [ 67 ] These surface models have previously been used to study the sodium storage in Fe 1− x S/MoS 2 composites, [ 62 ] as a monolayer for oxygen evolution reaction, [ 63 ] and for oxygen incorporation.…”

“…[ 67 ] These surface models have previously been used to study the sodium storage in Fe 1− x S/MoS 2 composites, [ 62 ] as a monolayer for oxygen evolution reaction, [ 63 ] and for oxygen incorporation. [ 65 ] The adsorption energies of LiPs on different carbon sulfur nitrogen structures have been well studied in the literature and are hence only discussed briefly here. [ 57,66,68–74 ] The adsorption of LiPs has been shown to be improved by the addition of vacancy defects on graphene, and by heteroatom doping of graphene sheets.…”

Photoinduced semiconductor-metal transition in ultrathin troilite FeS nanosheets to trigger efficient hydrogen evolution

“…The density functional theory (DFT) calculations (see Methods) are carried out to evaluate the HER activity of the superficial S and Fe sites 28 , as shown in the upper panel in Fig. 4b.…”

A surface oxidised Fe–S catalyst for the liquid phase hydrogenation of CO2

“…These results demonstrate that a significant amount of sulfur within an oxygen dominant surface is crucial for facilitating optimum catalytic activity. Hence, following our previous work with pyrrhotites 30,31 , density functional theory calculations have been employed to explore the role of sulfur atoms in the reduction of HCO 3 -, which is the dominant reactant species under the reaction conditions.…”