Materials Chemistry Frontiers, 5(3), pp.1301-1314
Mayenite-based electrides have been reported as promising support materials for heterogeneous catalysis. However, the current synthetic access to mayenite materials is limited by complex procedures far from industrial applicability and thus hinders research and application in a broader context. We report the first plasma-based synthesis of the mayenite-based electride [Ca24Al28O64]4+:(4e−) obtained by plasma treatment of oxygen-mayenite solid-reductant precursor mixtures. Aluminum and graphite as solid reductants: aluminum leads to enhanced secondary phase formation of krotite, while graphite leads to phase-pure samples. We further critically discuss challenges in determining electron concentration of the electrides. For this purpose, EPR-, DRUV/vis-spectroscopy, Rietveld refinement, and DSC-TG analysis under oxidizing atmosphere were applied and critically revised. We show the possibilities using the facile plasma-based synthesis as a scalable method to obtain semiconducting and close to metallic conducting electrides.
Authors: Sebastian Weber, Sebastian Schäfer, Mattia Saccoccio, Karsten Seidel, Holger Kohlmann, Roger Gläser, Stephan A. Schunk
