Preparing quasi-metal organic frameworks (Q-MOFs) with unsaturated metal sites is an effective approach for developing highly active MOF-based catalysts. In this study, we synthesized quasi ZIF-67 (Q-ZIF-67) with large-scale structural defects via controlled thermal partial deligandation at 310 °C under an air atmosphere. This process created additional open cobalt sites and hierarchical pores within ZIF-67 framework. The resulting Q-ZIF-67 exhibited enhanced catalytic activity for the hydrolysis of NaBH4, compared to pristine ZIF-67 and related cobalt oxide, due to a cooperative effect of Lewis acid centers and the coexistence of micro- and meso-/macropores. Hydrogen was successfully generated at a rate of 18500 mL.min-1g-1 over Q-ZIF-67 at room temperature without the need for a base, and with an activation energy of 53 kJ×mol-1 under mild conditions. In addition to the catalytic performance, we investigated the kinetics and thermodynamic parameters of the hydrogen generation reaction. Our mechanistic study revealed that strong acidity is critical for efficient chemo-hydrogen generation of NaBH4. We confirmed this by studying the isotope effect in a D2O system, which indicated that the cleavage of the O-H bond of water occurs in the rate-determining step.
