Ultrasmall nickel boride nanoparticles supported on reduced graphene oxide as a high-performance catalyst for hydrazine electrooxidation

Abstract

The direct hydrazine fuel cell is an attractive power generation technology for automotive applications. However, existing anode electrocatalysts generally suffer from low stability and problematic selectivity towards the non-Faradaic hydrazine (N2H4) decomposition. Herein, we report the fabrication of reduced graphene oxide (rGO)-supported nickel boride (Ni2B) nanocatalyst with a narrow size distribution around 1.5 nm by an ice-melting controlled NaBH4 reduction of Ni salt and graphene oxide. The chemical combination of Ni with B improves the intrinsic activity for N2H4 electrooxidation while suppressing the non-Faradaic N2H4 decomposition concurrently. Furthermore, Ni2B/rGO exhibits excellent stability with 91.4 % activity retention after 3000 cycles and a potential increment of only 13 mV after 50 h of constant-current measurement at 100 mA cm–2. Such stable performance is unprecedented for HzOR electrocatalysts. Our study presents the prospect of transition metal borides as high-performance HzOR electrocatalysts and may encourage further studies to explore their electrocatalytic applications.