Enhancing hydrogen storage properties of MgH_(2) using FeCoNiCrMn high entropy alloy catalysts

摘要

Herein,we report the successful preparation of the FeCoNiCrMn high entropy alloy(HEA)loaded MgH_(2) and HEA’s effect on the hydrogen storage properties of Mg/MgH_(2).The HEA shows high catalytic activity toward hydrogen dissociation and recombination reaction,and successfully suppressed activation energy of dehydrogenation reaction from 151.9 to 90.2 kJ mol-1.Moreover,part of Co and Ni can react with Mg,and produce Mg_(2) Co/Mg_(2) CoH 5 and Mg_(2) Ni/Mg_(2) NiH_(4) during the hydrogen storage processes,further en-hancing dehydrogenation reaction through the“hydrogen pumping”mechanism.Asa result,the MgH_(2)-5 wt%HEA composite can release 5.6 wt%of H_(2) at 280℃ within 10 min,and absorb 5.5 wt%H_(2) within 0.5 min at 150℃.The loaded HEA shows robustness against particle aggregation,leading to stable re-versible hydrogen storage processes at least 50 times.These findings show the synergistic effects of HEA on Mg-based hydrogen storage materials,providing an additional degree of freedom for catalyst design.