Synthesis and characterization of nanocrystalline NiO-GDC via sodium alginate-mediated ionic sol-gel method

In this study, nanocrystalline nickel oxide gadolinium-doped ceria (NiO-GDC) powder was synthesized in-situ using Na-Alginate as the template via ionic sol-gel technique. The effects of calcination time and temperature on the particle size and the physiochemical properties of nanocrystalline NiO-GDC are presented in this paper. Using this method, gel beads were formed by contacting sodium alginate solution as the gelling template and metal (gadolinium/cerium/Ni) nitrates as the precursor. The obtained nanocrystallites were characterized using Field Emission Scanning Electron Microscopy, powder X-ray diffraction, energy dispersive X-ray spectroscopy, thermo gravimetric analysis, nitrogen adsorption/desorption analysis, and Fourier transform infrared spectroscopy. It was observed that the increasing calcination temperature had affected both the particle size and the surface area of the NiO-GDC, whereas the increasing calcination time had only impacted the size of the particles. The smallest mesoporous nanocrystalline NiO-GDC powder (12.1225 ± 0.005 m2/g surface area), composed of cubic GDC (5.18 nm crystallite size) and cubic NiO (7.99 nm crystallite size) were synthesized at a calcination temperature of 500 °C for 2 h. This study hopes to inspire more researches on the ionic-gelation method for synthesizing other metal nanostructures as well as other reaction parameters.