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). • The effects of magnetic stirring, changing hydrolysis solution and tuning ammonia coordination number were investigated. • MgCl 2 and CoCl 2 solutions could improve hydrolysis kinetics of Zr(BH 4) 4 ·8NH 3. • Tuning ammonia coordination number(x) could effectively control hydrolysis properties of Zr(BH 4) 4 ·xNH 3. [ABSTRACT FROM AUTHOR]