Synthesis of Ni@SiO2 and Co@SiO2 nanomagnets after formation of NiO and Co2O3 nanoparticles at low temperatures using CaH2

Ni and Co based nanomaterials are widely used because of their magnetic and electric and also catalytic properties. They could be used as efficient electrocatalysts for oxygen reduction to replace fuel cell cathode materials. Further application may include the monitoring of the mechanical position of nanomotors. In this work NiO and Co2O3 nanoparticles were synthesized using one-pot pyrolysis. Oxide nanoparticles were covered with SiO2, and reduced at low temperature using CaH2 in vacuum-sealed tube resulting in core–shell structures with metal Ni and Co cores and SiO2 shell coatings to increase the obtained metal nanoparticles oxygen stability. Both Ni and Co metal oxides and their metal NPs crystal structure and morphology were analyzed using powder X-ray diffraction and transmission electron microscopy. Furthermore, Ni@SiO2 and Co@SiO2 nanoparticles magnetic behavior was measured with physical properties measurement system.