Light-activated hydrolysis properties of Mg-based materials

Abstract

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.