Nanocomposites and nanomaterials

MgH2–MgCl2 nanocomposites as efficient materials for hydrogen generation via hydrolysis 
Korablov D.S.1, Bezdorozhev O.V.1, Solonin Yu.M.1
1 Frantsevich Institute for Problems of Materials Science NAS of Ukraine. Krzhyzhanovsky str., 3, 03142, Kyiv, Ukraine. 
E-mail: funejima@gmail.com

Today, hydrogen is considered as one of the best options as a clean energy carrier when produced from renewable sources of energy. Hydrogen can offer a viable solution to many problems caused by climate change, air pollution, fluctuations in the green energy supply, etc., since it is renewable, eco-friendly and has a high energy density (120 MJ/kg). Production of hydrogen via hydrolysis of hydrides provides a promising method for hydrogen generation because of the high hydrogen yield at low operation temperature. 
In the search for advanced raw materials for hydrolysis, various hydrides (e.g., LiH, LiBH4, NaBH4, MgH2) and Al-, Mg-based alloys have been tested. Among them magnesium hydride (MgH2) is considered to be one of the most attractive candidates due to its high hydrogen capacity (7.6 wt.% H2 or 15.2 wt.% H2, when hydrolyzed), relatively low cost, and environmentally friendly hydrolysis byproducts. The main obstacle for practical application of MgH2 is the formation of a passive Mg(OH)2 layer on the MgH2 surface. Various approaches were used to address this problem, which includes nanostructuring, the addition of salts, acids, alkali metals, inert additives at ambient conditions or when under heating, ultrasonic irradiation, stirring. As it was shown in our recent study [1], nanostructuring of MgH2 with different additives under hydrogen atmosphere is an efficient way to improve the hydrolysis performance. Among the tested additives, the highest hydrolysis performance was obtained for materials with AlCl3 additive. 
In order to further improve the hydrolysis reaction of MgH2, we studied the effect of preparation procedures and hydrolysis parameters on the hydrogen generation kinetics of MgH2–MgCl2 composites prepared by reactive high-energy ball milling. The hydrogen generation performance in terms of conversion rate and hydrogen yield was determined volumetrically. 

1.	Korablov D.S., Bezdorozhev O.V., Gierlotka S., Yartys V.A., 		Solonin Yu.M. Effect of various additives on the hydrolysis performance of nanostructured MgH2 synthesized by high-energy ball milling in hydrogen // Powder Metall Met Ceram.-2021.-59.-P. 483-490.