Improved OER Performance on the Carbon Composite Electrode through Tailored Wettability

Abstract

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.

Single-Step Synthesis of Well-Ordered Hierarchical Nickel Nanostructures for Boosting the Oxygen Evolution Reaction

“…LSV was performed in a typical three-electrode system in the alkaline electrolyte (1 M KOH) at a scan rate of 5 mVs –1 . All of the experiments were performed using PCE as the electrode support due to negligible activity toward the OER and it resolves the bubble-related issue in the catalyst as it has hydrophobic nature that repels the generated oxygen gas bubbles . To activate the electrocatalyst-modified electrode, CV cycles were first performed at a scan rate of 500 mVs -1 until a uniform CV curve was attained.…”

“…PCE was fabricated using the previous reported method . A mixture of 10% (w/v) PMMA and graphite in chloroform in the ratio of 60:40 (w/v) was taken.…”

“…These two phases (graphite and PMMA) restrain the generation of bigger size bubbles and promote less electrode passivation. However, the highly rough surface of the PCE in comparison to the GCE leads to hydrophobicity …”

Reconstructing Oxygen Vacancies in the Bulk and Nickel Oxyhydroxide Overlayer to Promote the Hematite Photoanode for Photoelectrochemical Water Oxidation

“…The current strategies for enhancing PEC-WS performance are mainly through improving the light absorption efficiency, carrier separation efficiency, and transfer efficiency. − Numerous endeavors have demonstrated that surface engineering can effectively promote carrier separation and transfer by reducing surface recombination, commonly including oxygen evolution catalysts (e.g., FeOOH, NiOOH, Co–Pi), surface passivation layer (e.g., Al 2 O 3 , TiO 2 ), and dual-absorber configuration (e.g., Si/α-Fe 2 O 3 , BiVO 4 /TiO 2 ). For instance, Wang et al prepared the BiVO 4 photoanodes with surface catalyst modulation and showed that a mixture of NiOOH/NiO/Ni as oxygen evolution catalysts could remarkably improve the charge transfer efficiency .…”

Surface tailored graphite–polymer composite electrodes through cold plasma for electrochemical applications

“…[9][10][11] The plastic chip electrode (PCE) is one such polymer composite electrode developed by our group. [12] Having bulk conductivity coupled with self-standing flat and thin morphology, these electrodes helped in improving the efficiencies in sensing [13][14][15] electrocatalysis, [16] and electrometallurgy [17] applications. The PCE is fabricated by mixing its components in the solution phase followed by evaporation of the solvent under ambient conditions.…”