Synthesis of highly activated magnesium by niobium and tantalum gel oxide catalyst

Abstract

As catalysts to improve the kinetics of the reaction between Mg and H2, Nb2O5, Ta2O5, and Nb2O5Ta2O5 mixture gels with and without heat treatment were synthesized using simple sol-gel methods. Furthermore, MgH2 was ball milled to superficially disperse 1 mol% of each oxide for 2 h, which was ten times shorter than that of previous works. All the oxides show catalytic effects on using easier and simpler synthesis processes. The catalysis of Nb oxides is better than that of Ta oxides and mixtures. The as-synthesized Nb2O5 gel without heat treatment is the best catalyst and improves hydrogenation kinetics at room temperature. The Nb2O5 gel with higher catalysis is further reduced compared to the heat-treated one because the gel oxide is more unstable owing to the lesser network between Nb and O atoms due to the existence of OH groups. By using gel oxides, highly activated Mg can be synthesized under milder conditions compared with previous cases.