Hydrolysis of Mg-based materials is a promising technology for the development of portable hydrogen fuel cells. However, the Mg(OH)2 layer impedes the diffusion of water molecules into inner particles, resulting in sluggish hydrolysis performance. The hydrolysis performances of Mg-based materials (Mg, MgH2, MgH2-BM and MgH2-RBM) with water are effectively improved under light-activation. The hydrolysis performance could be tailored by the light energy (frequency and intensity). The combination of ball-milling and light-activation could further enhance the hydrolysis performance of MgH2. In particular, the hydrolysis yield of MgH2-RBM reached 95.7% of the theoretical yield under 90 W green light-activation. Thus, rasing the light energy (by using purple light and UV, or higher power lights) and the combination of ball-milling could lead to better hydrolysis performance of Mg-based materials. The Mg(OH)2 layer was considered as a barrier to MgH2 hydrolysis of MgH2. Interestingly, under light-activation, the Mg(OH)2 layer can act as a catalyst to enhance the decomposition of MgH2, and improve the hydrolysis yield and kinetics of Mg-based materials.
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