Enhancing ZnO monolayer nanosheets for photocatalysis: the role of FeSn and RuSn (n = 0–3) doping in electronic and structural properties

Abstract

The present investigation utilizes density functional theory (DFT) to elucidate the influence of iron (Fe) and ruthenium (Ru) as dopants, alongside sulfur (S) co-doping, on the electronic properties and photocatalytic properties of zinc oxide (ZnO) monolayer nanosheets. The findings indicate that the integration of Fe and Ru dopants serves to augment structural stability while concomitantly diminishing the bandgap energy through an elevation of the valence band maximum (VBM). Doping of Fe and Ru along with co-doping up to three sulfur atoms into the ZnO lattice has been observed to result in a compromise of structural stability while concurrently enhancing the specific surface area. The introduction of sulfur expands the bandgap in Fe-doped ZnO nanosheets, enhancing the VBM energy, while for Ru-doped ZnO nanosheets, sulfur doping narrows the bandgap. This effect is especially notable in RuS₃ co-doped nanosheets, making them well-suited as a photocatalyst for the overall water splitting process at pH = 7. Furthermore, the increased probability of effective electron–hole pair separation, combined with a bandgap of 3.52 eV, positions FeS-co-doped ZnO as a promising photocatalytic material for the generation of hydrogen via water splitting under near-ultraviolet illumination.