Kinetic enhancement of MgH2 using Co0.2Ni0.8/Fe2NiO4 bimetallic catalyst

MgH 2 is a promising energy storage material due to its high hydrogen capacity and cost-effectiveness. However, its practical application is limited by a high dehydrogenation temperature and sluggish kinetics. While doping with Fe 2 NiO 4 alone has been shown to lower the initial dehydrogenation temperature, its kinetic performance remains insufficient. To address this, this study synthesizes a novel Co 0.2 Ni 0.8 /Fe 2 NiO 4 (CNFO) bimetallic catalyst via hydrothermal treatment, calcination, and ultrasonic methods. The results demonstrate that 15 wt% CNFO is the optimal doping concentration, under which MgH 2 exhibits outstanding hydrogen desorption performance, delivering 5.82 wt% H 2 in just 10 min under 260 °C. In comparison, although 40 wt% is the optimal loading for Fe 2 NiO 4 alone, it releases merely 3.79 wt% H 2 in 60 min under 300 °C. Regarding absorption, MgH 2 + 15 wt% CNFO absorbs 4.94 wt% H 2 in 9 min under 120 °C and 3 MPa, whereas MgH 2 + 40 wt% Fe 2 NiO 4 absorbs only 4.50 wt% H 2 in 9 min under 300 °C and 4 MPa. Therefore, the incorporation of Co0.2Ni0.8 is thus shown to be highly effective. Comprehensive characterization suggests that this improvement arises from the synergistic interaction between Co and Ni dispersed on the matrix surface, which effectively facilitates the reversible transformation between Mg 2 Ni and Mg 2 NiH 4 , thereby intensifying the so-called “hydrogen pump” effect. Altogether, this finding opens up a new avenue for the fabrication of MgH 2 catalysts with enhanced efficiency.