Improved LPG sensing properties of nickel doped cobalt ferrites derived from metallurgical wastes

Abstract

In this work, an improved gas sensing response of nickel doped cobalt ferrite, Co0.87Ni0.13Fe2O4, nanoparticles synthesized from metallurgical wastes are demonstrated without any deliberate doping. The morphology and magnetic properties of the nanoparticles were characterized and correlated directly with their superior sensing behavior. The nanoparticles compacted into pellets were used to sense liquefied petroleum gas (LPG), and the results are compared with undoped CoFe2O4 to critically discuss and establish the mechanisms leading to improvement in sensing. The sensing properties were evaluated as a function of operating temperature and the response-recovery time at predetermined LPG concentrations of 500 and 5000 ppm in air. The activated Co0.87Ni0.13Fe2O4 sensor demonstrates high sensing response, speedy response-recovery time, good reproduc-ibility, and long-term stability compared to undoped CoFe2O4. The mechanism for the superior gas sensing properties of Co0.87Ni0.13Fe2O4 ferrite is correlated with the resistance change of Co0.87Ni0.13Fe2O4 nanoparticles assisted by the oxygen adsorption on the nanoparticles. This study demonstrates the possibility of developing a potential inexpensive Co0.87Ni0.13Fe2O4 nanoparticle-based sensor directly from metallurgical wastes to be more efficient for sensing LPG.