Synthesis and characterization of nanocrystalline zinc aluminate spinel powder by sol–gel method

Single-phase nanocrystalline zinc aluminate (ZnAl2O4) spinel powder has been synthesized by the sol–gel method. Zinc aluminate nanoparticles were formed at 600 °C, which is at much lower temperature than by solid state reactions. Formation of ZnAl2O4 and their particle size depend on the calcination temperature. Calcination temperature also affects the specific surface area and pore volume. The nanocrystalline zinc aluminate was characterized by powder X-ray diffraction, FT-IR spectroscopy, thermal gravimetric analysis, diffuse reflectance spectroscopy, surface area measurements, field emission scanning electron microscopy coupled with energy dispersive X-ray analysis and transmission electron microscopy. Catalytic reactivity of nanocrystalline zinc aluminate was tested for the reduction of 4-nitrophenol to 4-aminophenol using NaBH4.