Dandelion-like ZIF-67 supported ternary transition metal borides as efficient hydrolysis catalysts for KBH4

The development of high-efficient and low-cost catalysts is crucial for promoting KBH4 hydrolysis to produce hydrogen. Herein, ZIF-67 supported cobalt-molybdenum-nickel based boride (Co-Mo-Ni-B/ZIF-67) nanocomposites with dandelion-like morphology were designed as catalysts of KBH4 hydrolysis reaction and were synthesized via the chemical reduction process. Moreover, the element ratio and the loading amount of Co-Mo-Ni-B were optimized, and effects of KBH4 concentration, KOH concentration, and reaction temperature on catalytic performances were studied. As expected, ZIF-67 substrate avoids the agglomeration of amorphous Co-Mo-Ni-B, and the synergy between ZIF-67 and uniformly dispersed Co-Mo-Ni-B active substances accelerates hydrogen generation rate. As a result, the maximum hydrogen generation rate of 17400 mL min-1 g-1 is achieved with the optimized KOH concentration of 10% and KBH4 concentration of 6% at the reaction temperature of 30 degrees C. In addition, Co-Mo-Ni-B/ZIF-67 exhibits moderate durability performance with a cyclic retention rate of 51.9 % after five cycles. This dandelion-like structure design provides an idea for the development of efficient catalyst for hydrolysis of borohydrides.