Iron‐Doped NiCo2O4 Nanoparticles: Synthesis via Homogeneous Precipitation Method and Studies on their Peroxidase‐like Activity

Abstract

AbstractThe present study reports the synthesis of iron‐doped NiCo2O4 nanoparticles (Ni1−xFexCo2O4) using homogeneous precipitation method followed by calcination. The precursors (Ni−Co layered double hydroxides) and iron‐doped NiCo2O4 nanoparticles were characterized using various analytical techniques. XRD results indicate formation of iron‐doped NiCo2O4 nanoparticles up to x=0.5 and when x≥0.7, there is also formation of α‐Fe2O3. TEM images show formation of nanorods composed of nanoparticles in the iron‐doped NiCo2O4 nanoparticles. DRS results demonstrate change in optical properties upon doping of iron in the NiCo2O4 nanoparticles. M−H measurements show soft ferromagnetic behavior of pure and iron‐doped NiCo2O4 nanoparticles at 300 K. At 5 K, soft ferromagnetic behavior is observed up to x=0.3 in Ni1−xFexCo2O4 nanoparticles, and when x=0.7, strong ferromagnetic behavior is observed. When x=0.5, “wasp‐waist” behavior is observed. The ZFC‐FC measurements show single blocking temperature up to x=0.3 while two blocking temperatures are observed when x=0.5. When x=0.7, the blocking temperature is above room temperature. After characterization, the peroxidase‐like activity using iron‐doped NiCo2O4 nanoparticles as catalyst was investigated using oxidation of 3,3′,5,5′‐tetramethyl benzidine as substrate.