Improving hydrogen sorption performances of MgH2 through nanoconfinement in a mesoporous CoS nano-boxes scaffold

For the first time, structure-modified CoS-nanoboxes (CoS-NBs) scaffold as a multifunctional Supporting material has been developed by using a template-consumption method for nanoconfinement of MgH2 particles within its mesoporous structure (denoted as MgH2@CoS-NBs). Microstructural observations via transmission electron microscopy (TEM) reveal the uniform distribution of MgH2 nanocrystals within the mesoporous networks of CoS-NBs scaffold and the surface decoration of MgH2 crystals by in-situ formed MgS phase. The peculiar core-shell structured morphology of MgH2 nanocrystals and the nano-size effect notably enhances the thermodynamic properties of MgH2 through the reduction in hydriding and dehydriding enthalpies (-65.6 +/- 1.1 and 68.1 +/- 1.4 kJ mol(-1) H-2, respectively). Moreover, the improved hydrogen sorption kinetics can be attributed to the catalytic effect of MgS through reducing the intrinsic kinetic energy barriers for both hydriding and dehydriding (57.4 +/- 2.2 and 120.8 +/- 3.2 kJ mol(-1) H-2, respectively). The nano-size effect of nanoconfined Mg/MgH2 crystals, the catalyzing effect of MgS and the multifunctional role of CoS-NBs scaffold are likely to be synergistically contributed to the superior hydrogen sorption performances of MgH2@CoS-NBs composite, as compared to the pure MgH2.

Automated summary

A novel scaffold material (CoS-NBs) was developed, successfully nanoconfining MgH2 particles within its mesoporous structure, resulting in the MgH2@CoS-NBs composite. The uniform distribution of MgH2 nanocrystals within the scaffold, surface decoration by MgS phase, and nano-size effect notably enhance the thermodynamic properties and hydrogen sorption kinetics.