TY - JOUR

T1 - Magnetically separable Co@Co–Al–O catalysts for NaBH4 hydrolysis: Water activation impact on activity and stability

AU - Komova, Oksana V.

AU - Ozerova, Anna M.

AU - Simagina, Valentina I.

AU - Danilova, Natalya A.

AU - Lipatnikova, Inna L.

AU - Rogov, Vladimir A.

AU - Bulavchenko, Olga A.

AU - Chesalov, Yuriy A.

AU - Ishchenko, Arcady V.

AU - Netskina, Olga V.

N1 - This work was supported by the Ministry of Science and Higher Education of the Russian Federation within the governmental order for Boreskov Institute of Catalysis [project FWUR-2024- 0034]. Magnetically separable Co@Co–Al–O catalysts for NaBH4 hydrolysis: Water activation impact on activity and stability / O. V. Komova, A. M. Ozerova, V. I. Simagina, N. A. Danilova, I. L. Lipatnikova, V. A. Rogov, O. A. Bulavchenko, Y. A. Chesalov, A. V. Ishchenko, O. V. Netskina // International Journal of Hydrogen Energy. - Т. 182. - С. 151823. DOI: 10.1016/j.ijhydene.2025.151823

PY - 2025/10/27

Y1 - 2025/10/27

N2 - The kinetic isotope effect (kH/kD, KIE) during replacement of H2O with D2O is a valuable tool for evaluating water activation in NaBH4 hydrolysis. However, its correlation with catalyst activity and stability remains unclear. In this study, two magnetically separable catalysts of different activity with a Co0 core and a “Co–Al–O″ shell were synthesized via galvanic replacement. Compared to the non-catalytic process, water activation on the catalyst surface occurs more efficiently, resulting in reduced kH/kD. The active Co-Omax catalyst contains a higher amount of oxidized phases (Co3O4, CoO, Co(OH)2, Co–Al layered double hydroxide), which reduce to the active component in the reaction medium. Their deficiency in Co-Omin causes a sharp activity decline and a drastic increase in kH/kD (>5) upon reuse, indicating a shift toward the non-catalytic pathway. In contrast, highly active Co-Omax demonstrates an efficient catalytic water activation supported by a stable kH/kD of 2.34 ± 0.05 over five cycles. The observed monotonic decrease in H2 generation rate for this catalyst is probably attributable to the hydride activation step.

AB - The kinetic isotope effect (kH/kD, KIE) during replacement of H2O with D2O is a valuable tool for evaluating water activation in NaBH4 hydrolysis. However, its correlation with catalyst activity and stability remains unclear. In this study, two magnetically separable catalysts of different activity with a Co0 core and a “Co–Al–O″ shell were synthesized via galvanic replacement. Compared to the non-catalytic process, water activation on the catalyst surface occurs more efficiently, resulting in reduced kH/kD. The active Co-Omax catalyst contains a higher amount of oxidized phases (Co3O4, CoO, Co(OH)2, Co–Al layered double hydroxide), which reduce to the active component in the reaction medium. Their deficiency in Co-Omin causes a sharp activity decline and a drastic increase in kH/kD (>5) upon reuse, indicating a shift toward the non-catalytic pathway. In contrast, highly active Co-Omax demonstrates an efficient catalytic water activation supported by a stable kH/kD of 2.34 ± 0.05 over five cycles. The observed monotonic decrease in H2 generation rate for this catalyst is probably attributable to the hydride activation step.

KW - Co0 core

KW - Co–Al–O shell

KW - Galvanic replacement

KW - H2 generation

KW - Kinetic isotope effect

KW - Magnetically separable catalyst

KW - NaBH4 hydrolysis

UR - https://www.mendeley.com/catalogue/799ccf8e-bc02-319e-840f-cf2d80b76a0d/

UR - https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=105017572533&origin=inward

U2 - 10.1016/j.ijhydene.2025.151823

DO - 10.1016/j.ijhydene.2025.151823

M3 - Article

VL - 182

JO - International Journal of Hydrogen Energy

JF - International Journal of Hydrogen Energy

SN - 0360-3199

M1 - 151823

ER -