Ammonia borane modified zirconium borohydride octaammoniate with enhanced dehydrogenation properties

Abstract

A new complex system, Zr(BH₄)₄·8NH₃–nNH₃BH₃ (n = 2, 3, 4, 5), was prepared via ball milling of Zr(BH₄)₄·8NH₃ and NH₃BH₃ (AB). The combination strategy effectively suppressed ammonia release and reduced the dehydrogenation temperature when compared to the individual compounds. In the optimized composition, Zr(BH₄)₄·8NH₃–4AB, the hydrogen purity was improved to 96.1 mol% and 7.0 wt% of hydrogen was released at 100 °C. These remarkable improvements are attributed to the interaction between AB and the NH₃ group in Zr(BH₄)₄·8NH₃, which enables a more active interaction of H^δ+⋯^−δH. These advanced dehydrogenation properties suggest that Zr(BH₄)₄·8NH₃–4AB is a promising candidate for potential hydrogen storage applications.