Magnetically recyclable Co/ZnO@NiFe2O4 nanoparticles as highly active and reusable catalysts for hydrazine monohydrate hydrogen generation

Abstract

This research investigates the improvement of novel and cost-effective highly magnetic nanoparticle (NP) catalysts for hydrazine monohydrate dehydrogenation, which are viewed as some of the greatest solid chemical hydrogen storage materials because of their high gravimetric hydrogen storage capacity. The improvement of a new catalytic material, Co supported on ZnO@NiFe₂O₄ NPs, was also studied. The experimental results indicate that the resultant Co/ZnO@NiFe₂O₄ NPs (2.0 wt% Co) exhibits excellent catalytic performance, 100% H₂ selectivity and recyclability for hydrogen generation from hydrazine monohydrate (N₂H₄·H₂O) at 25 °C in alkaline solution conditions. The turnover frequency (TOF) value was approximately 4445.37 h⁻¹, which is higher than that obtained with 0.5 wt% Co NPs (TOF value 997.42 h⁻¹). Moreover, Co/ZnO@NiFe₂O₄ demonstrates outstanding catalytic performance and excellent recycle stability through high hydrazine monohydrate dehydrogenation. The superior catalytic properties may be the result of electronic interactions between Co, Zn and Ni NPs. The tested catalysts were easily recovered by utilizing a permanent magnet and were reused for up to 15 cycles without losing their characteristic catalytic activity. In summary, Co/ZnO@NiFe₂O₄ NP catalysts have been successfully developed and show a good future application potential.