Improvement on hydrogen generation properties of Zr(BH4)4·8NH3

Hydrolysis of Zr(BH 4 ) 4 ·8NH 3 in deionized water can generate high purity hydrogen at room temperature. However, the sluggish hydrolysis kinetics of Zr(BH 4 ) 4 ·8NH 3 hinders its practical use. To improve its hydrogen generation properties, the effects of magnetic stirring, changing hydrolysis solution and tuning the ammonia coordination number on the hydrolysis properties of Zr(BH 4 ) 4 ·8NH 3 were investigated. Results show that both changing hydrolysis solution and tuning the ammonia coordination number can enhance the hydrolysis kinetics. The hydrolysis kinetics properties of Zr(BH 4 ) 4 ·8NH 3 were significantly improved in MgCl 2 and CoCl 2 solutions. The Zr(BH 4 ) 4 ·xNH 3 (x ≤ 8) samples were synthesized by a ball-milling method with different ammonization time (10, 60 and 180 min). Both the hydrolysis kinetics and hydrogen yield of Zr(BH 4 ) 4 ·xNH 3 (x ≤ 8) were enhanced as the ammonia coordination number (x) decreased. Thus, tuning ammonia coordination number is an effective way to control the hydrolysis properties of Zr(BH 4 ) 4 ·xNH 3 (x ≤ 8).