Lithium-Doped Silica-Rich MIL-101(Cr) for Enhanced Hydrogen Uptake

Metal-organic frameworks (MOFs) show promising characteristics for hydrogen storage application. In this direction, modification of under-utilized large pore cavities of MOFs has been extensively explored as a promising strategy to further enhance the hydrogen storage properties of MOFs. Here, we described a simple methodology to enhance the hydrogen uptake properties of RHA incorporated MIL-101 (RHA-MIL-101, where RHA is rice husk ash-a waste material) by controlled doping of Li⁺ ions. The hydrogen gas uptake of Li-doped RHA-MIL-101 is significantly higher (up to 72 %) compared to the undoped RHA-MIL-101, where the content of Li⁺ ions doping greatly influenced the hydrogen uptake properties. We attributed the observed enhancement in the hydrogen gas uptake of Li-doped RHA-MIL-101 to the favorable Li⁺ ion-to-H₂ interactions and the cooperative effect of silanol bonds of silica-rich rice-husk ash incorporated in MIL-101.