Improved OER Performance on the Carbon Composite Electrode through Tailored Wettability

This work reports an improved oxygen evolution reaction (OER) activity on a carbon–polymer composite-based tailored electrode, the plastic chip electrode (PCE). Glassy carbon electrodes (GCEs) have been often used as an electrode platform in water-splitting experiments, mostly due to their suitable physicochemical properties and omnipresence. However, the OER kinetics on carbon electrodes are reported to be limited. Passivation of the electrode surface due to slow scavenging of the formed oxygen is presumably the major reason for such a decline. Attempts have been made to improve the OER efficiency on the carbon electrode by improving its hydrophobicity and hence reducing the size of the passivating oxygen bubble. In this direction, we put forward an altogether different approach. A two-component polymer composite working electrode has been used. Two distinct phases of varying wettability discourage the bigger size bubble and help less passivation of the electrodes. Moreover, the highly rough surface of PCE compared to that of GCE increases the hydrophobicity of the tailored electrode. These two factors show improved OER activity, which has been demonstrated using Ru-based catalysts since the Ru-based catalysts are considered as a benchmark for OER. A Ru–triazine covalent organic framework catalyst has been loaded on PCE. Bare and modified electrodes were characterized for their scanning electron microscopy, water wettability, and electrochemical active surface area measurements. Followed by various OER parameters, such as linear sweep voltammetry and stability (chronoamperometry), Tafel slopes have been evaluated. The charge-transfer resistance has been measured using electrochemical impedance spectroscopy analysis. The activity of the modified PCE has been compared with that of the GCE, and the yield of oxygen has been compared using gas chromatography.