Modulating Force of Nucleated Hydrogen Bubble Adhesion to Boost Electrochemical Water Splitting

Abstract

AbstractIn electrochemical hydrogen evolution reaction (HER), the produced hydrogen gas bubbles often adhered to the electrode surface and blocked the active catalytic site. While different catalysts are developed to improve the catalytic performance of HER, the design of a durable and universal approach for minimizing the force of nucleated hydrogen gas‐bubble adhesion to prevent blockage of electrocatalytic sites because of bubbles‐adhesion is unprecedented. Generally, buoyancy should outweigh the capillary force to remove nucleated bubbles, which means these forces ratio, Eötvös number Eo > 1. Herein, a chemically reactive multilayer coating on an electrode is reported to chemically modulate the adhesion force of nucleated gas‐bubble on the electrode. A dual modified coating on Ni‐foam provided a non‐adhesive superaerophobicity with nucleated bubble adhesion force of 4.6 ± 0.3 µN and displayed superior HER performance with lower overpotential (333 to 250 mV) at 100 mA cm−2 with respect to bare Ni‐foam. The chemically‐modulated low bubble‐adhesion facilitates the early removal of nucleated tiny hydrogen gas bubbles with a minimum size of 0.64 mm and Eo = 0.05 to keep catalytic sites available for superior electrochemical HER. Such a positive impact of the prepared coating is also noted for various other electrodes.