Local Atomic and Electronic Structure of Iron-Sulfide Nanosheets

• Published in: Surface investigation, x-ray, synchrotron and neutron techniques x-ray, synchrotron and neutron techniques, 2021-05, Vol.15 (3), p.570-574
• Main Authors: Soldatov, M. A., Medvedev, P. V., Gorban, I. E., Liu, Q., Wei, S., Soldatov, A. V.
• Format: Article
• Language: English
• Subjects: Absorption spectra; Atomic structure; Catalytic activity; Chemistry and Materials Science; Electronic structure; Energy gap; Hydrogen evolution reactions; Iron; Iron sulfides; Materials Science; Nanosheets; Oxygen atoms; Spectral sensitivity; Surfaces and Interfaces; Thin Films; X ray absorption
• ISSN: 1027-4510; 1819-7094
• DOI: 10.1134/S1027451021030320

In this paper, we calculate the geometry and band structure of iron sulfide (mackinawite) nanosheets. This material is one of the representatives of a new class of two-dimensional nanocatalysts for the hydrogen evolution reaction. Calculations show the absence of a band gap for model structures of crystalline and nanoscale mackinawite. In the model of oxidized nanoscale mackinawite, half of the sulfur atoms are replaced by oxygen atoms, and the band gap is 0.37 eV. The band-gap broadening can explain the appearance of catalytic activity in oxidized nanoscale mackinawite. The X-ray absorption spectra show a high sensitivity of the method to changes in the local atomic environment, especially in the first coordination sphere of iron atoms. The calculated model spectra allow determination of the features of the local atomic and electronic structure of the nanoscale mackinawite surface during the hydrogen evolution reaction.