Synthesis and electrocatalytic properties for p-nitrophenol deduction of nano-scaled M3O4 (M = Fe, Co) products with different shapes

Spinel-structured M₃O₄ (M=Fe, Co) samples with different shapes were synthesised mainly via a hydrothermal procedure. All Fe₃O₄ samples were prepared using a one-step process; however, all Co₃O₄ samples were synthesised via two-step paths, namely their precursors were prepared first then the resultant oxide products were obtained by calcining their precursors at a certain temperature. The samples were characterised by thermogravimetric analysis, X-ray diffraction, transmission electron microscopy, high-resolution electron microscopy and field-emission scanning electron microscopy measurements, respectively. The results showed that plate-, particle- and sphere-like Fe₃O₄ and sheet-, particle- and tube-like Co₃O₄ samples were obtained successfully. The electrocatalytic properties of the samples modified on a glassy carbon electrode were investigated, and the results indicated that Fe₃O₄ and Co₃O₄ samples with different shapes exhibited different enhanced electrocatalytic activity for p-nitrophenol reduction, and Fe₃O₄ and Co₃O₄ nanoparticles all showed the highest elctrocatalytic activity.