Synthesis of metal aluminate nanoparticles by sol–gel method and studies on their reactivity

Nanosized metal aluminates (CoAl2O4, NiAl2O4 and CuAl2O4) were prepared by sol–gel method. The formation of metal aluminate nanoparticles and their particle size were found to depend upon the calcination temperature. CoAl2O4 nanoparticles were obtained at 700 °C, which is much lower than that required for its preparation through solid state reactions. The formation of NiAl2O4 and CuAl2O4 nanoparticles occurs at 900 °C and 800 °C, respectively. Characterization of the metal aluminate nanoparticles were carried out by X-ray diffraction, thermal gravimetric analysis, UV–vis diffuse reflectance spectroscopy, FT-IR spectroscopy, scanning electron microscopy and transmission electron microscopy. The chemical reactivity of the synthesized metal aluminate nanoparticles were also tested using paraoxon destructive adsorption and catalytic reduction of 4-nitro phenol.

► Metal aluminate nanoparticles were synthesized by a simple sol–gel method without using any gelation agent. ► Destructive adsorption of paraoxon on metal aluminate nanoparticles demonstrated for the first time. ► Catalytic reduction of 4-nitrophenol by the metal aluminate nanoparticles indicate high reactivity.