Sensing mechanism of hydrogen storage on Li, Na and K-decorated Ti${}_2$C

The adsorption of H${}_2$ molecules on Li, Na and K-decorated MXenes (Ti${}_2$C) has been investigated with first-principles calculations. A detailed examination of the adsorption mechanism of the Li, Na and K-decorated systems was presented by charge population analysis, electron density and partial density of states calculations. The results show that Li-decorated Ti${}_2$C system was found suitable for hydrogen storage. The maximum storage capacity about 4.33 wt% with a suitable average adsorption energy of − 0.26 eV/H${}_2$ can be obtained for two Li atoms, which adsorbed on both sides of the Ti${}_2$C. It indicates that Li-decorated Ti${}_2$C is of great significance for the wide application of MXenes in the field of hydrogen absorption.