Mechanochemistry for Energy Materials: Impact of High‐Energy Milling on Chemical, Electric and Thermal Transport Properties of Chalcopyrite CuFeS<sub>2</sub> Nanoparticles
Peter Baláž, Erika Dutková, Matěj Baláž, Róbert Džunda, J. Navrátil, K. Knı́žek, Petr Levinský, J. Hejtmánek
Abstract
Abstract Chalcopyrite CuFeS 2 , a semiconductor with applications in chemical sector and energy conversion engineering, was synthetized in a planetary mill from elemental precursors. The synthesis is environmentally friendly, waste‐free and inexpensive. The synthesized nano‐powders were characterized by XRD, SEM, EDX, BET and UV/Vis techniques, tests of chemical reactivity and, namely, thermoelectric performance of sintered ceramics followed. The crystallite size of ∼13 nm and the strain of ∼17 were calculated for CuFeS 2 powders milled for 60, 120, 180 and 240 min, respectively. The evolution of characteristic band gaps, Eg , and the rate constant of leaching, k , of nano‐powders are corroborated by the universal evolution of the parameter S BET /X ( S BET ‐specific surface area, X ‐crystallinity) introduced for complex characterization of mechanochemically activated solids in various fields such as chemical engineering and/or energy conversion. The focus on non‐doped semiconducting CuFeS 2 enabled to assess the role of impurities, which critically and often negatively influence the thermoelectric properties.