Fuel dependent combustion synthesis and electrochemical characteristics of nickel cobalt oxide nanoparticles

The electrochemical activity of the nickel–cobalt oxide (NiCoO2) nanoparticles (NPs) is strongly dependent upon its morphology, composition, phase, and the presence of functional groups and metal ions (Ni and Co) on the surface of NiCoO2 NPs. These characteristics can be tailored by the choice of synthesis method and reaction parameters adopted for its preparation. In this work, we have synthesized two different samples of NiCoO2 by solution combustion method employing glucose and thioacetamide as fuels. The electrocatalyst synthesized using glucose as fuel (S1) exhibited enhanced reactivity as compared to the sample prepared using thioacetamide (S2) as fuel. The reduction of the glucose during the preparation of sample S1 resulted in the enhancement in electrochemical surface area (ECSA). The high ECSA results in a higher rate of charge storage reaction. The above analysis is further supported using electrochemical impedance spectroscopy (EIS) data. The high pseudo-capacitance and low charge transfer resistance of sample S1 are attributed to the high ECSA and optimized surface energy. Thus, the fuel variation in the nanoparticle fabrication plays a critical role in the enhancement of the supercapacitor activity of the electrocatalyst.