TY - JOUR

T1 - Mechanically ground C12A7:e electride

T2 - Structure, properties, and catalytic activity in the ammonia decomposition

AU - Kapishnikov, Aleksandr V.

AU - Shlyapin, Dmitry A.

AU - Borisov, Vadim A.

AU - Anoshkina, Elena A.

AU - Stoyanovskii, Vladimir O.

AU - Volodin, Alexander M.

AU - Vedyagin, Aleksey A.

N1 - Aleksandr V. Kapishnikov, Dmitry A. Shlyapin, Vadim A. Borisov, Elena A. Anoshkina, Vladimir O. Stoyanovskii, Alexander M. Volodin, Aleksey A. Vedyagin, Mechanically ground C12A7:e electride: structure, properties, and catalytic activity in the ammonia decomposition, Ceramics International, Volume 52, Issue 24, Part A, 2026, Pages 41968-41976, ISSN 0272-8842, https://doi.org/10.1016/j.ceramint.2026.07.104. This study was funded by the Ministry of Science and Higher Education of the Russian Federation within the governmental assignments for Boreskov Institute of Catalysis (projects FWUR-2024-0034 and FWUR-2024-0039) and Novosibirsk State University (project FSUS2024-0020).

PY - 2026/10

Y1 - 2026/10

N2 - The features of the evolution of the structural and spectroscopic characteristics and catalytic properties of C12A7:e− electride samples obtained by a mechanical grinding of a solidified drop of mayenite melt and additionally treated in hydrogen and oxygen environments were studied. As a result of such treatments, the replacement of electrons by hydride ions (C12A7:H−) and oxygen anions (C12A7:O2−) has occurred. The X-ray diffraction analysis revealed an increase in the unit cell parameter of the mayenite phase to 12.042 Å upon the treatment in hydrogen, which is most likely associated with the introduction of hydride ions into its structure. This is consistent with the appearance of an absorption band in the region of ∼3.135 eV, characteristic of hydride ions, in the UV-vis spectra of such samples. The electron paramagnetic resonance method has shown that the concentration of paramagnetic F+-like sites in the C12A7:e− electride sample remained practically unchanged when it was calcined in air to a temperature of 200 °C. A further increase in temperature to 550 °C resulted in the complete demolition of these sites and the disappearance of the absorption band at ∼2.8 eV, characteristic of the electride, in the UV-vis spectra. The activity of the C12A7:e−, C12A7:H−, and C12A7:O2− samples was studied in the test reaction of catalytic ammonia decomposition. These experiments confirmed the applicability of the testing procedure for examining mayenite samples with an extremely low specific surface area (∼1 m2/g). It was also shown that the catalytic activity of mayenite in this reaction is sensitive to the composition of the anionic sublattice of mayenite. The best activity was demonstrated by the C12A7:H− sample, which was treated in hydrogen.

AB - The features of the evolution of the structural and spectroscopic characteristics and catalytic properties of C12A7:e− electride samples obtained by a mechanical grinding of a solidified drop of mayenite melt and additionally treated in hydrogen and oxygen environments were studied. As a result of such treatments, the replacement of electrons by hydride ions (C12A7:H−) and oxygen anions (C12A7:O2−) has occurred. The X-ray diffraction analysis revealed an increase in the unit cell parameter of the mayenite phase to 12.042 Å upon the treatment in hydrogen, which is most likely associated with the introduction of hydride ions into its structure. This is consistent with the appearance of an absorption band in the region of ∼3.135 eV, characteristic of hydride ions, in the UV-vis spectra of such samples. The electron paramagnetic resonance method has shown that the concentration of paramagnetic F+-like sites in the C12A7:e− electride sample remained practically unchanged when it was calcined in air to a temperature of 200 °C. A further increase in temperature to 550 °C resulted in the complete demolition of these sites and the disappearance of the absorption band at ∼2.8 eV, characteristic of the electride, in the UV-vis spectra. The activity of the C12A7:e−, C12A7:H−, and C12A7:O2− samples was studied in the test reaction of catalytic ammonia decomposition. These experiments confirmed the applicability of the testing procedure for examining mayenite samples with an extremely low specific surface area (∼1 m2/g). It was also shown that the catalytic activity of mayenite in this reaction is sensitive to the composition of the anionic sublattice of mayenite. The best activity was demonstrated by the C12A7:H− sample, which was treated in hydrogen.

KW - Ammonia decomposition

KW - Anionic sublattice

KW - Characterization

KW - Mayenite

KW - Mechanical grinding

KW - Майенит

KW - Механическое измельчение

KW - Анионная подрешетка

KW - Характеризация

KW - Разложение аммиака

UR - https://www.mendeley.com/catalogue/bffc6ec5-0cb6-3876-baf7-0af99352a1d4/

UR - https://www.scopus.com/pages/publications/105044224697

U2 - 10.1016/j.ceramint.2026.07.104

DO - 10.1016/j.ceramint.2026.07.104

M3 - Article

VL - 52

SP - 41968

EP - 41976

JO - Ceramics International

JF - Ceramics International

SN - 0272-8842

IS - 24

ER -