Rice leaves microstructure-inspired high-efficiency electrodes for green hydrogen production†

Abstract

Hydrogen production via water electrolysis is deemed a prime candidate for large-scale commercial green hydrogen generation. However, during the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), bubble accumulation on the electrode surface substantially elevates the required voltage and diminishes electrolysis efficiency. In this work, we demonstrated a rice leaves-inspired anisotropic microstructured gas conduction electrode (Ni-conduction) that can rapidly detach bubbles from the anisotropic microstructure. The microstructured grooves on the electrode surface lower the interface energy and modify bubble detachment dynamics, enabling swift bubble release and directed bubble flow along the microstructured channels. As a result, the Ni-conduction achieves a reduction in HER/OER overpotential, reaching values of 92/123 mV at 10 mA cm⁻². This performance significantly surpasses the performance of a flat nickel electrode (Ni-smooth), necessitating an overpotential of 183/176 mV under identical conditions. Furthermore, the assembled Ni-conduction||Ni-conduction overall water-splitting device only needs a cell voltage of 1.53 V to reach 10 mA cm⁻². Our research emphasizes the significance of wettability design in electrode microstructure to enhance mass transfer and optimize water splitting efficiency, presenting novel strategies for the development of superior gas-evolution electrodes.