CoAl2O4 nanoparticles modified carbon nanofibers as high-efficiency bifunctional electrocatalyst: An efficient electrochemical aqueous asymmetric supercapacitors and non-enzymatic electrochemical sensors

Abstract

The thriving energy demand of the gradually increasing population and modernized life style requires development in energy storage devices for usage in commercial electronic devices. In this particular work, we have explored electrochemical performances of bimetallic oxide CoAl2O4 and tuned its performance by decorating it on the carbon nanofibers. The CoAl2O4/CNFs are synthesized by deep eutectic solvents based hydrothermal method. The synthesized CoAl2O4 nanoparticle was found electrochemically active and the incorporation of CNFs end up boosting, its electrochemical performances as battery-type electrode. The obtained nanocomposites were characterized by various techniques. The electrochemically active CoAl2O4/CNFs exhibited 2.2-fold higher charge storage capacity than CoAl2O4. The CoAl2O4/CNFs exhibited specific capacity as high as 132 C/g at a constant applied current density of 1 A/g in 1 M KOH. The asymmetric device fabricated with CoAl2O4/CNFs electrodes exhibited excellent energy density of 20 Wh/kg at power density of 3000 W/kg. The CoAl2O4/CNFs electrode long-term stability has been minutely observed; the high Coulombic efficiency of 90% and high rate of capacity retention 95 %. In this work, an enzyme-free electrochemical sensor based on CoAl2O4/CNFs composite was developed for the detection of luteolin (LUT). Further modification of CoAl2O4/CNFs composite can improve the high surface area and catalytic capability of the composites. Under the optimal detection conditions, the prepared sensor has good linearity in the detection of LUT within range 30 nM − 73.5 μM with a limit of detection (LOD) of 0.0124 μM (12.4 nM). The stability and selectivity of the sensor is high, and can be used to detect LUT in various real samples.