Hydrogen desorption mechanism of 2NaBH4 + MgH2 composite prepared by high-energy ball milling

The desorption mechanism of 2NaBH4 + MgH2 composite has been investigated. The results show that the chemical interaction between MgH2 and NaBH4 is capable of decreasing the dehydrogenation temperature with respect to the single compounds. The dehydriding reaction starts at around 320 °C with the desorption of the MgH2 to Mg and proceeds via the chemical dismutation of NaBH4 in NaH and an intermediate specie. In situ synchrotron X-ray powder diffraction indicates that MgB2 is one of the final reaction products.