Co and Co 3 O 4 in the Hydrolysis of Boron-Containing Hydrides: H 2 O Activation on the Metal and Oxide Active Centers

• Published in: Materials Vol. 17; no. 8
• Main Authors: Butenko, Vladislav R, Komova, Oksana V, Simagina, Valentina I, Lipatnikova, Inna L, Ozerova, Anna M, Danilova, Natalya A, Rogov, Vladimir A, Odegova, Galina V, Bulavchenko, Olga A, Chesalov, Yuriy A, Netskina, Olga V
• Format: Journal Article
• Language: English
• Published: Switzerland 13-04-2024
• Subjects: DFT; sodium borohydride; ethylenediamine bisborane; cobalt; rate-determining step; activation; ammonia borane; cobalt oxide; hydrogen production; hydrolysis
• ISSN: 1996-1944; 1996-1944

This work focuses on the comparison of H
evolution in the hydrolysis of boron-containing hydrides (NaBH
, NH
BH
, and (CH
NH
BH
)
) over the Co metal catalyst and the Co
O
-based catalysts. The Co
O
catalysts were activated in the reaction medium, and a small amount of CuO was added to activate Co
O
under the action of weaker reducers (NH
BH
, (CH
NH
BH
)
). The high activity of Co
O
has been previously associated with its reduced states (nanosized CoB
). The performed DFT modeling shows that activating water on the metal-like surface requires overcoming a higher energy barrier compared to hydride activation. The novelty of this study lies in its focus on understanding the impact of the remaining cobalt oxide phase. The XRD, TPR H
, TEM, Raman, and ATR FTIR confirm the formation of oxygen vacancies in the Co
O
structure in the reaction medium, which increases the amount of adsorbed water. The kinetic isotopic effect measurements in D
O, as well as DFT modeling, reveal differences in water activation between Co and Co
O
-based catalysts. It can be assumed that the oxide phase serves not only as a precursor and support for the reduced nanosized cobalt active component but also as a key catalyst component that improves water activation.