Charge-Induced Defective MOF-801 with Enhanced Sorption Heat for Efficient Hydrogen Storage

Metal-organic frameworks (MOFs) are considered ideal candidates for H₂ physisorption materials due to their high surface area and tunable pore structures/environments. However, their interaction with hydrogen is too weak to fully exploit their surface area advantages, necessitating the exploration of effective adsorption enhancement strategies. Here, a defective MOF-801 is reported as an H₂ physisorption material and investigate the enhancement of hydrogen adsorption by charge-inducing. Based on the excellent stability of MOF-801, the material retains good porosity after acid vapor etching, compared to the initial MOF-801 (810 m² g^-1), the surface area reaching up to 970 m² g^-1. The mild etching method leads to excess charges around the zirconium (Zr) of MOF-801, forming specific defective sites with excellent adsorption heat, inducing hydrogen polarization, and enhancing hydrogen capacity. The total H₂ uptake increases from 5.02 wt.% (MOF-801) to 8.58 wt.% (Cl@MOF-801) at 77 K and 80 bar. Additionally, the material exhibits excellent cycling performance, stably cycling 10 times at 8 MPa and maintaining a total capacity of 8.56 wt%. The results reveal that tuning H₂ adsorption heat by charge induction is a promising strategy to exploit the potential of porous materials for efficient H₂ storage.