Bioinspired Underwater Superoleophobic Electrodes with Superior Kolbe Electrochemical Performances

Abstract Although water is the life force of our planet, the global risk of water is becoming a hotspot all over the world. Therefore, wastewater treatment and reuse have attracted much attention, especially for the household wastewater containing surfactants. Kolbe electrolysis is an important organic electrochemical reaction. However, the resultant hydrophobic products are prone to adhere to traditional oleophilic platinum (Pt) electrode, hindering the charge transfer and resulting in a short working life of Kolbe electrolysis. Here, inspired by the biological materials with underwater superwettability, simultaneous underwater superoleophobic and superhydrophilic Pt electrodes with multiscale structures are fabricated, demonstrating superior electrochemical performances compared to the conventional underwater oleophilic flat Pt electrodes. The working life can be enhanced from about 5800 to 30 000 s, arising from the efficient repellency of multiscale structured Pt electrodes toward the hydrophobic products and the resultant clean electrode surface. The long working life of the underwater superoleophobic Pt electrode can be maintained even under a wide variety of experimental conditions, exhibiting its universality. The presented bioinspired approach should extend the application of the Kolbe electrolysis and provide a promising solution for the wastewater treatment to alleviate the growing global water crisis.