Nano-structure Engineering With an Ultrasonic-assisted DHBT Technique to Improve the Hydrogen Evolution Reactions in Alkaline Water Electrolysis

Alkaline water electrolysis (AWE) is considered to be a core technology for green hydrogen production given its reasonable cost-effectiveness and approachability. However, the large activation loss from the hydrogen evolution reaction (HER) still hinders high efficiency of the resulting devices. Here, we apply ultrasonic-assisted dynamic hydrogen bubble templating (U-DHBT) technology over electrodeposition to improve the HER of the Ni electrodes used in alkaline electrolysis. We verified that the ultrasonic fields offer a facile fabrication of a 3D hierarchical porous structure, exhibiting an enlarged electrochemical active area and HER kinetics. The Ni foam with the deposited U-DHBT exhibits 30 ~ 60% lower overvoltage of 126 mV compared to those of bare Ni foam (150 mV) and the Electrodeposition (165 mV) and immersed samples (210 mV) at a current density of 10 mA/cm². While bare Ni exhibits a degradation rate of 2.44 mV/h, the U-DHBT electrode shows a significantly lower rate of 0.98 mV/h, demonstrating superior stability over 50 h of operation. This study provides a promising strategy by which to engineer nanostructures to improve the performance of electrochemical devices as well as AWE.