Suman Pokhrel, Muhammad Ali Martuza, Jan Derk Groeneveld, Marco Schowalter, Andreas Rosenauer, Johannes Birkenstock, Lutz M?dler

Powder Technology 465 (2025): 121318

https://doi.org/10.1016/j.powtec.2025.121318

The synthesis of Cu?.?S, ZnS, and Cu?.?S-ZnS composite nanoparticles is achieved via reactive spray combustion, wherein rapid vaporization of thiophene initiates micro-explosions that promote high-temperature vapor-phase reactions under reducing conditions. High-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) analyses reveal that the synthesized nanoparticles consist of agglomerated spherical primary crystallites, with average sizes of 12.2 nm for Cu?.?S, 10 nm for ZnS, and 10.8 nm for the Cu?.?S-ZnS composite. Elemental analysis via energy-dispersive X-ray spectroscopy (EDX) coupled with scanning transmission electron microscopy (STEM) confirms homogeneous spatial distribution of Cu and S in Cu?.?S, elevated surface oxygen content in ZnS attributed to physisorption, and substantial Cu incorporation into the ZnS lattice within the Cu?.?S-ZnS composite system. Structural analysis indicates that the contrast features observed in Cu?.?S, ZnS, and Cu-Zn mixed sulfides are consistent with their respective crystallographic symmetries, where sulfur atoms adopt well-ordered lattice positions, while copper exhibits partial site occupancy and electron density disorder attributed to the comparable ionic radii of Cu²⁺ and Zn²⁺ ions. This study underscores the efficacy of oxygen-deficient, reducing flame environments in facilitating the synthesis of binary and mixed-metal sulfide nanomaterials, enabling the formation of metastable phases providing a scalable, cost-effective route for producing advanced functional materials with broad application potential.