Spatial decoupling strategy boosted alkaline hydrogen evolution for an efficient solar-driven AEM electrolyzer

Abstract

Electrolytic water splitting using renewable energy sources, such as solar power, provides a green and sustainable approach for hydrogen production. Anion exchange membrane (AEM) electrolyzers present substantial commercial prospects; however, the rate of hydrogen evolution reaction (HER) in alkaline electrolytes is limited by the water dissociation step. In this work, we fabricated an N-doped Ni substrate for loading ultrafine Pt nanoparticles, realizing spatial decoupling of the reaction process to break the limitation of water dissociation, where the N-doped Ni substrate and Pt nanoparticles facilitate the supply of ample H* and H₂ release, respectively. The prepared Pt–N–Ni/NC with extremely low Pt loading (1.0 wt%) requires only 15 and 149 mV overpotentials to reach current densities of 10 and 1000 mA cm⁻², respectively. When assembled into an AEM electrolyzer, the system requires a cell voltage of only 1.75 V to achieve a current density of 1000 mA cm⁻². Notably, the solar-driven AEM electrolyzer demonstrates a current density of 1390 mA cm⁻² with a solar-to-hydrogen efficiency (STH) of 8.27%. This study proposes a strategy to achieve efficient utilization and performance improvement of precious metals, promoting the development of efficient green hydrogen production.