Influence of a three-dimensional honeycomb Fe/N-MXene catalyst on the hydrogen storage performance of MgH2

In this study, a three-dimensional honeycomb Fe/N-MXene composite was prepared by heating the mixture of the prefabricated honeycomb N-MXene composite with Fe 4 [Fe(CN) 6 ] 3 (referred to as PB tube). Subsequently, it was introduced to enhance the hydrogen storage properties of MgH 2 through ball milling. Experimental results demonstrate that the initial dehydrogenation temperature of the MgH 2 +Fe/N-MXene composite system is 198 °C, which is significantly lower than that of pure MgH 2 . Additionally, the absorption/dehydrogenation activation energies of MgH 2 +Fe/N-MXene composites were reduced by 50.9 kJ mol −1 and 68.1 kJ mol −1 , respectively, compared with MgH 2 . After 20 min at 100 °C, 5.14 wt% H 2 is absorbed. Mechanism analysis reveals that the presence of Fe prolongs the length of the Mg–H bond and weakens its bond energy. The unique honeycomb structure of N-MXene provides more nucleation sites for hydrogen atoms for adsorption and storage. Under the catalytic action of Fe/N-MXene composite, the hydrogen storage capacity of MgH 2 is significantly improved.