Enhanced room-temperature hydrogen storage by CuNi nanoparticles decorated in metal-organic framework UiO-66(Zr)

This study demonstrates the significant effect of incorporating inexpensive transition metal nanoparticles into metal-organic frameworks (MOFs) to improve their room-temperature hydrogen storage properties. Low-cost nanoparticles (Cu, Ni, and CuNi) were incorporated into UiO-66(Zr) via the double-solvent approach (DSA) plus chemical reduction processes. All composites exhibited higher hydrogen storage capacity compared to pure UiO-66 at both room temperature and 60 bar. Notably, the hydrogen spillover efficiency of CuNi nanoparticles loaded in UiO-66 was comparable to that of MOF adsorbents embedded with noble metals such as Pd and Pt. The hydrogen storage capacity of CuNi@UiO-66 was significantly increased from 0.20 wt% to 0.74 wt%. DFT calculations showed that the CuNi alloys facilitated the adsorption and dissociation of hydrogen molecules in comparison to the single metal nanoparticles, thus favoring the hydrogen spillover effect and improving the hydrogen storage performance. This work demonstrates the potential of designing MOF loaded with inexpensive metal nanoparticles for optimized room-temperature hydrogen storage.