Hydrogen storage properties of MgH2 + 20 wt.% Na2WO4 composite

Abstract

The hydrogen storage properties of MgH2 ball milled with 20wt.% Na2WO4 have been investigated. The MgH2+20wt.% Na2WO4 composite has favorable hydrogenation and dehydrogenation properties as well as low decomposition temperature. When compared with the pristine MgH2, the total hydrogen absorption capacity of MgH2+20wt.% Na2WO4 composite increased from 0.98wt.% to 2.27wt.% in 20min at 423K, and the maximum hydrogen desorption capacity of MgH2+20wt.% Na2WO4 composite increased by 1.3wt.% at 573K. DTA and the Kissinger desorption kinetics analysis results indicated that the dehydrogenation activation energy of MgH2+20wt.% Na2WO4 composite is 83.10kJ/mol, 39kJ/mol lower than that of the pristine MgH2. The XRD pattern provided that the in-situ formed MgWO4, acting as the catalyst during ball milling, improved the hydrogen storage properties of MgH2.