Effect of different cobalt loadings on the electrochemical performance of aluminum pillared clay-supported cobalt towards glucose oxidation

Abstract

This work is focused on our further efforts to improve the electrochemical performance of cobalt oxide supported on aluminum pillared clay (CoAP) towards glucose oxidation [1]. To this end, the effect of different cobalt loadings onto the electrochemical performance of CoAP was investigated. Four CoAP samples, with theoretical cobalt loadings corresponding to 1, 3, 5, 10 wt% introduced to the pillared clay (x%CoAP), were prepared using the incipient wetness impregnation method [2]. Furthermore, electrodes based on the obtained materials were prepared in the form of carbon paste electrode (CP-x%CoAP) with the same x%CoAP to carbon black (CB) mass ratio. The electrochemical performance of each of CP-x%CoAP was investigated using the cyclic voltammetry and chronoamperometry in 1M NaOH with and without glucose. The electrochemical measurements were carried out in a three-electrode system with an Ag/AgCl and platinum rod as the reference and counter electrodes, respectively. Preliminary results revealed that cobalt content in the pillared clay (AP) significantly affected both the intensity of the current peak of glucose oxidation and sensitivity. As cobalt loading increased (up to 5%) the glucose current response and sensitivity increased. On the other hand, the electrochemical behavior of the electrode with 10% cobalt loading deviated from this trend. The obtained results indicate that the variation of cobalt content could be used for fine-tuning of the electrocatalytic performance of CP-CoAP. The characterization of the synthesized materials required for establishing the correlation between the physical-chemical properties and the corresponding electrochemical performance of CP-CoAP is ongoing.