Lithium‐Ion‐Induced Enhanced Hydrogen Uptake over MIL‐101(Cr) Metal‐Organic Frameworks

A robust and straightforward strategy is demonstrated to improve MIL‐101(Cr) hydrogen uptake performance through systematic Li+ ion doping. Several spectroanalytical techniques are employed to investigate the physical, chemical, morphological, and pore textural properties of the synthesized Li‐doped MIL‐101(Cr) and to establish the incorporation of Li+ ions in Li‐MIL‐101(Cr) frameworks. Notably, it is observed that the pore textural characteristics of Li‐doped MIL‐101(Cr) can be fine tuned by varying Li+ ions loading. The hydrogen uptake capacity of 2.74 wt% at 77 K and 1 bar is achieved with Li‐doped MIL‐101(Cr), which is almost double as compared to the pristine MIL‐101(Cr). The experimental findings demonstrate the significance of Li+ ions doping content on the hydrogen uptake performance of Li‐doped MIL‐101(Cr). The observed remarkable improvement in the H2 uptake capacity of Li‐doped MIL‐101(Cr) can be attributed to the enhanced interaction between the doped Li+ ions in the frameworks and H2 gas. Furthermore, hydrogen adsorption isotherms data of these frameworks are best fitted with three‐parameter nonlinear adsorption equilibrium isotherm equations (R2 ≥ 0.999), indicating the nonuniform multilayer adsorption behavior due to the heterogeneous surface of Li‐doped MIL‐101(Cr).