Kinetics of MgH2 formation by ball milling

Hydrogen (H-2) absorption by metals, metal alloys, and more complex solids is a crucial issue on the road to the efficient H-2 storage required by the hydrogen economy. The present study examines the reaction between Mg powder and gaseous H-2 under ball milling conditions as a specific casestudy. Based on accurate kineticevidence, we show that H-2 absorptionis governed bya combinationof statistical and chemical contributions related, respectively, to the inherent nature of ball milling and the chemistry of the MgeH(2) system. The combination of the two factors determines the shape of the H-2 absorption curve. Therefore, chemical information can be only obtained by disentangling the two contributions. To this aim, we propose a general method that can be extended to other chemical transformations activated by ball milling. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.