Catalytic behavior of magnetic Ni-Zn alloy.

Ni-Zn alloy with various compositions of zinc was synthesised using a sodium borohydride-assisted chemical reduction method. The as-synthesised Ni-Zn alloy samples were annealed at 673 K for 2 h in nitrogen atmosphere. The atomic absorption spectroscopy measurement reveals the zinc-rich composition in all alloy samples. Field emission scanning electron microscopy shows that the surface morphology of Ni-Zn alloys has a flake-like nature. The X-ray diffraction pattern of as-synthesised samples shows the presence of nickel hydroxide while the annealed samples show formation of Ni2Zn11 phase. The phase transition temperature of as-synthesised Ni-Zn alloy was observed using differential scanning calorimetry and crystallization temperature changes with zinc composition was also examined. The room temperature magnetic behaviour of both as-synthesised and annealed samples was studied using vibrating sample magnetometer. This shows that as-synthesised samples have a weak ferromagnetic nature and annealed samples have a soft ferromagnetic nature. The decreasing magnetization value and Curie temperature with zinc composition was observed. The catalytic activity of Ni-Zn alloy was studied for the reduction of 4-nitrophenol. The rate constant value changes with zinc composition in the alloy. [ABSTRACT FROM AUTHOR]