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

Abstract

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 H 2 uptake capacity of Li‐doped MIL‐101(Cr) can be attributed to the enhanced interaction between the doped Li + ions in the frameworks and H 2 gas. Furthermore, hydrogen adsorption isotherms data of these frameworks are best fitted with three‐parameter nonlinear adsorption equilibrium isotherm equations ( R 2 ≥ 0.999), indicating the nonuniform multilayer adsorption behavior due to the heterogeneous surface of Li‐doped MIL‐101(Cr).