LAUSR

Pulsed laser irradiation of an equimolar mixture of FeS2 and CoS2 onto a Ta substrate results in the one-step formation of bimetallic iron cobalt sulfide. The use of complementary analytical techniques, such as scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, high-resolution electron microscopy, and electron diffraction, confirmed the presence of nanocrystalline cobaltpentlandite [FeCo8S8] and maghemite [γ-Fe2O3]. The mechanism by which this occurs involves the reactive interaction of laser-ionized Fe, Co, and S species, which subsequently undergo rapid non-equilibrium cooling and deposition. The higher deposition tendency of CoS2 along with iron ions/atoms leads to the formation of FeCo8S8. This proposed mechanism is supported by density functional theory (DFT), which provides a deeper understanding of the higher thermodynamic stability of Fe in Co1−xFexS2 compared with Co in Fe1−xCoxS2. The FeCo8S8-based deposit exhibited enhanced catalytic efficiency for methylene blue daylight-driven and Fenton-like degradation. In contrast, for solar light-driven degradation of sulfamethoxazole and trimethoprim, the FeCo8S8-based deposit does not show enhanced catalytic activity compared to FeS2 and CoS2. Additionally, electrochemical testing of the oxygen evolution reaction (OER) revealed significantly improved performance for the FeCo8S8-based deposit compared to FeS2 and CoS2 individually.