Comparison of Hydrothermally-Grown vs Electrodeposited Cobalt Sulfide Nanostructures as Modified Electrodes for Oxygen Evolution and Electrochemical Sensing Applications

A wide range of electrocatalysts have been developed and implemented for electrochemical applications over the last decades, with researchers typically using either a conventional synthesis method (followed by drop-casting or spray-coating onto the electrode), or directly electrodepositing the catalyst. However, a clear comparison of the different materials synthesis techniques, and how this affects the electrochemical applications, has been less explored. Herein, we report a direct comparison of fabricated cobalt sulfide (CoS) nanostructure-based electrodes prepared by two different methods for two applications: (a) electrochemical water splitting and (b) glucose sensing. CoS is grown in the form of nanoflowers and nanosheets via facile one-pot hydrothermal (HT) and electrodeposition (ED) methods, respectively. Characterization is performed using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). It is observed that the as-fabricated CoS-ED electrode demonstrated enhanced oxygen evolution reaction (OER) performance, a lower overpotential (similar to 166 mV at 10 mA cm(-2)), lower charge transfer resistance (similar to 372 Omega), a lower Tafel slope (86 mV dec(-1)), and better stability compared to the CoS-HT electrode. Moreover, the CoS-ED electrode-based sensor also exhibited better performance, higher sensitivity, better selectivity, and good stability for electrochemical glucose detection compared to the CoS-HT sensor. (C) 2022 The Electrochemical Society (ECS). Published on behalf of ECS by IOP Publishing Limited.

Automated summary

This study directly compares cobalt sulfide nanostructure-based electrodes prepared by two different methods for electrochemical water splitting and glucose sensing. The results show that the electrode prepared by electrodepositing cobalt sulfide demonstrates better performance in oxygen evolution reaction and glucose detection compared to the electrode prepared by hydrothermal method.