Investigating of hydrolysis kinetics and catalytic mechanism of MgH2 catalyzed by TM/MOF (TM=Ni, Zn, Co)

The hydrolysis of MgH2 for hydrogen production can significantly advance the development of mobile fuel cells, making it essential to address the issue of poor hydrolysis kinetics of MgH2. In this study, we investigated the preparation of MgH2+x wt.% TM/MOF (x = 2, 4, 8; TM = Ni, Zn, Co) composites using ball milling technology with different contents of TM/MOF catalysts. Multiple hydrolysis tests were conducted at different temperatures. The experimental results were analyzed to plot hydrolysis kinetics curves and fit the activation energy. XRD and SEM were employed to observe the phase composition and surface morphology of the composites before and after hydrolysis, elucidating the hydrolysis mechanism. The results indicated that the TM/MOF catalysts activated the surface activity of MgH2 and significantly improved the hydrolysis kinetics. The hydrogen production rates for MgH2 + 8 wt% TM/MOF (TM = Ni, Zn, Co) were 39.33, 47.56, and 33.67 mL g−1 s−1, respectively, with H2 yield of 1810, 1987, and 1870 mL g−1, and apparent activation energy of 21.9 ± 1.5, 22.6 ± 1.0, and 18.6 ± 0.7 kJ mol−1. TM/MOF catalyst significantly influences the catalytic activity of MgH2 hydrolysis, so it is of great significance to study the hydrolysis of MgH2 to produce hydrogen.