Hydrogen generation by hydrolysis of metals and hydrides for portable energy supply
Authors:   Vernadsky Institute of General and Inorganic Chemistry of NAS of Ukraine, Kutsyi A. , Kytsya A. ,   Department of Physical Chemistry of Fossil Fuels InPOCC, Yartys V. ,   Institute for Energy Technology, Zavaliy I. ,   Karpenko Physico-Mechanical Institute of the NAS of Ukraine, Pirskyy Yu. ,   Vernadsky Institute of General and Inorganic Chemistry of NAS of Ukraine,   Vernadsky Institute of General and Inorganic Chemistry of NAS of Ukraine, Solonin J. ,   I. M. Frantsevich Institute for Problems of Materials Science of the NAS of Ukraine, Berezovets V. ,   Karpenko Physico-Mechanical Institute of the NAS of Ukraine, Manilevich F. ,   Vernadsky Institute of General and Inorganic Chemistry of NAS of Ukraine, Verbovytskyy Yu. ,   Karpenko Physico-Mechanical Institute of the NAS of Ukraine
Published: December 2021

NATO project G 5233 “Portable energy supply” was executed by 4 teams (Institute for Energy Technology, Norway and 3 Institutes of the National Academy of Sciences of Ukraine). G5233 Project was focused on the development of hydrogen fueled portable energy supply systems integrating hydrogen generation and storage units based on use of light metals, metal and complex hydride materials and portable fuel cells. The weight efficient energy supply device was developed by using these selected materials and performance-optimised NaBH4 complex hydride. Besides, various new relevant units of equipment for the samples preparation and characterization were ordered and accommodated in the participants labs and the program of training of young scientists at IFE, Norway was accomplished. Different types of materials for hydrogen generation were synthesized and characterized (activated aluminium alloys, Mg-Al alloys, MgH2 and their composites, NaBH4 with catalytic additives). The challenging objective of reaching a completeness of the hydrolysis of MgH2 was achieved; the reaction conditions were optimized and the particular focus applications integrating efficient hydrogen generation systems were identified. The mechanism and the kinetics model of the hydrolysis process of MgH2 in water solutions have been proposed which successfully describe the experimental data. In parallel with the hydrolysis reaction resulting in hydrogen generation and formation of Mg(OH)2 , the process involves passivation of the MgH2 surface by the formed Mg(OH)2 precipitate followed by its re-passivation with the rate constants of these processes being established. Increase of the concentration of MgCl2 leads to just a minor increase in the rate constant of the interaction of MgH2 with water but leads to a sharp increase of the rate constant of the repassivation of MgH2 surface. To achieve efficient hydrolysis of NaBH4 , different types of catalysts (heterogeneous on the basis of Pt and "homogeneous" - salts of Ni+2 and Co+2) were studied and optimized. Several systems were selected as candidates to provide the required hydrogen flow to operate a 30 W fuel cell over a given time exceeding 1 hour, based on a use of inexpensive and affordable hydrogen-containing materials and catalytic additives. 3 individual hydrolysis workstations (1 in Norway and 2 in Ukraine) were built, tested and optimized. The plan of the work to reach the objectives of the Project G5233 “Portable energy supply” is completely accomplished, all the milestones are successfully fulfilled and the overall goal of the Project is reached.